SCXI ™ SCXI-1121 User Manual Four-Channel Isolated Universal Transducer Module for Signal Conditioning SCXI-1121 User Manual September 1999 Edition Part Number 320426C-01
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Important Information Warranty The SCXI-1121 is warranted against defects in materials and workmanship for a period of one year from the date of shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace equipment that proves to be defective during the warranty period. This warranty includes parts and labor.
Contents About This Manual Conventions ...................................................................................................................xi Related Documentation..................................................................................................xii Chapter 1 Introduction What Your Kit Should Contain .....................................................................................1-2 Optional Software ........................................................................
Contents Chapter 3 Theory of Operation Functional Overview ..................................................................................................... 3-1 SCXIbus Connector ........................................................................................ 3-3 SCXIbus Connector Signal Descriptions........................................................ 3-4 Digital Interface.............................................................................................................
Contents 2. Module Programming ...................................................................5-10 3. Programming the Slot 0 Hardscan Circuitry.................................5-13 4. Acquisition Enable, Triggering, and Servicing.............................5-14 Scanning Examples........................................................................................................5-15 Example 1........................................................................................................
Contents Figures Figure 2-1. Figure 2-2. Figure 2-3. Figure 2-4. Figure 2-9. Figure 2-10. Figure 2-11. Figure 2-12. Figure 2-13. Figure 2-14. Figure 2-15. Figure 2-16. Figure 2-17. Figure 2-18. Figure 2-19. SCXI-1121 General Parts Locator Diagram ......................................... 2-2 SCXI-1121 Detailed Parts Locator Diagram ........................................ 2-3 SCXI-1121 Front Connector Pin Assignment ......................................
Contents Figure E-2. Figure E-3. Figure E-4. SCXI-1180 Rear Connections ...............................................................E-9 SCXI-1180 Front Panel Installation ......................................................E-10 Cover Removal......................................................................................E-11 Figure F-1. Figure F-2. Figure F-3. Revision A and B SCXI-1121 Signal Conditioning Module ................F-1 Revision A and B SCXI-1121 General Parts Locator Diagram ....
About This Manual This manual describes the electrical and mechanical aspects of the SCXI-1121 and contains information concerning its operation and programming. The SCXI-1121 is a member of the National Instruments Signal Conditioning eXtensions for Instrumentation (SCXI) Series for the National Instruments data acquisition plug-in boards.
About This Manual monospace Text in this font denotes text or characters that you should enter from the keyboard, sections of code, programming examples, and syntax examples. This font is also used for the proper names of disk drives, paths, directories, programs, subprograms, subroutines, device names, functions, operations, variables, filenames and extensions, and code excerpts. monospace italic Italic text in this font denotes text that is a placeholder for a word or value that you must supply.
1 Introduction This chapter describes the SCXI-1121; lists the contents of your SCXI-1121 kit; describes the optional software, optional equipment, and custom cables; and explains how to unpack the SCXI-1121 kit. The SCXI-1121 consists of four isolated input channels and four isolated excitation channels. The SCXI-1121 is a module for signal conditioning of strain gauges, RTDs, thermistors, thermocouples, volt and millivolt sources, 4 to 20 mA current sources, and 0 to 20 mA process-current sources.
Chapter 1 Introduction What Your Kit Should Contain The contents of the SCXI-1121 kit (part number 776572-21) are listed as follows: Kit Component Part Number SCXI-1121 module 181700-01 SCXI-1121 User Manual 320426-01 If your kit is missing any of the components, contact National Instruments. Optional Software This manual contains complete instructions for directly programming the SCXI-1121. You can order separate software packages for controlling the SCXI-1121 from National Instruments.
Chapter 1 Introduction for DOS and Visual Basic, Turbo Pascal, Microsoft C with SDK, and Borland C++ for Windows. NI-DAQ software for DOS/Windows/LabWindows is on high-density 5.25 in. and 3.5 in. diskettes. You can use the SCXI-1121, together with the Lab-LC or NB Series data acquisition boards, with LabVIEW for Macintosh, a software system that features interactive graphics, a state-of-the-art user interface, and a powerful graphical programming language.
Chapter 1 Introduction Optional Equipment Equipment Part Number NB6 cable 0.5 m 181305-01 1.
Chapter 1 Introduction Refer to the Signal Connections section in Chapter 2, Configuration and Installation, and to Appendix E, SCXI-1121 Cabling, for additional information on cabling, connectors, and adapters. Custom Cables The SCXI-1121 rear signal connector is a 50-pin male ribbon-cable header. The manufacturer part number used by National Instruments for this header is as follows: • AMP Inc.
Chapter 1 Introduction Unpacking Your SCXI-1121 module is shipped in an antistatic package to prevent electrostatic damage to the module. Several components on the module can be damaged by electrostatic discharge. To avoid such damage in handling the module, take the following precautions. SCXI-1121 User Manual • Touch the antistatic package to a metal part of your SCXI chassis before removing the module from the package.
2 Configuration and Installation This chapter describes the SCXI-1121 jumper configurations, installation of the SCXI-1121 into the SCXI chassis, signal connections to the SCXI-1121, and cable wiring. Module Configuration The SCXI-1121 contains 49 jumpers that are shown in the parts locator diagrams in Figures 2-1 and 2-2. Figure 2-1.
Chapter 2 Configuration and Installation Figure 2-2. SCXI-1121 Detailed Parts Locator Diagram The jumpers are used as follows: • • SCXI-1121 User Manual Fixed jumpers – On Revision A and B modules, jumper W32 is unused and should not be connected. – Jumper W45 is reserved and should not be reconfigured.
Chapter 2 Configuration and Installation – Jumpers W3, W19, W29, and W41 configure the first-stage gain of input channels 0 through 3, respectively. – Jumpers W4, W20, W30, and W42 configure the second-stage gain of input channels 0 through 3, respectively. – Jumpers W5, W21, W31, and W43 configure the first-stage filtering of input channels 0 through 3, respectively.
Chapter 2 Configuration and Installation On Revision C or later modules, jumper W44 does not exist. SLOT0SEL* is always buffered to the INTR* line. Jumper W38 Position 1 connects, after buffering, the SCXIbus MISO line to the SERDATOUT pin of the rear signal connector. In this setting, along with the proper setting of W32, the data acquisition board can read the Module ID Register of the SCXI-1121.
Chapter 2 Configuration and Installation W38 in its factory default position (position 1). On all but one of the SCXI-1121s that are cabled to the data acquisition board, move jumper W32 to position 3. It does not matter which of the SCXI-1121 modules that are cabled to the data acquisition board has jumper W32 set to position 1. If you have different types of modules cabled to the data acquisition board, those different modules will have jumpers similar to W38 and W32 of the SCXI-1121.
Chapter 2 Configuration and Installation Table 2-1. Digital Signal Connections, Jumper Settings (Continued) Jumper W44 W32 W32 Description Factory setting (Revision A and B modules only) Configuration 3 • 2 • 1 • 3 • 2 • 1 • 3 • 2 • 1 • Fatory-default setting; connects pullup to SERDATOUT (Revision C and later) Parking position (not connected on Revision A or B modules) Analog Configuration The SCXI-1121 has 45 analog configuration jumpers.
Chapter 2 Configuration and Installation Position AB-R1 connects the analog reference to the SCXIbus guard. Position A-R0R1 is the parking position and the factory setting. Position AB-R2 enables the Pseudodifferential Reference mode and connects the analog reference to the OUTREF pin on the rear signal connector. Select this mode when the SCXI-1121 has to operate with data acquisition boards that have a nonreferenced single-ended (NRSE) input.
Chapter 2 Configuration and Installation Input Channel Jumpers Gain Jumpers Each input channel has two gain stages. The first gain stage provides gains of 1, 10, 50, and 100 and the second stage provides gains of 1, 2, 5, 10, and 20. Tables 2-3 and 2-4 show how to set up the gain for each channel. Table 2-3.
Chapter 2 Configuration and Installation Filter Jumpers Two-stage filtering is also available on your SCXI-1121 module. The first stage is located in the isolated section of the input channel, whereas the second stage is located in the nonisolated section of the input channel. This permits a higher signal-to-noise ratio by eliminating the noise generated by the isolation amplifier. Furthermore, two filter bandwidths are available—10 kHz and 4 Hz. Table 2-5.
Chapter 2 Configuration and Installation Table 2-6.
Chapter 2 Configuration and Installation Table 2-7. Maximum Load per Excitation Channel Excitation Level Maximum Load 3.333 V 28 mA 10 V 14 mA 0.150 mA 10 kΩ 0.450 mA 10 kΩ After selecting the excitation mode of operation desired—Voltage or Current—as described in the previous section, use Table 2-8 to set your SCXI-1121 for the level of operation. Your SCXI-1121 is shipped with the Voltage mode set to 3.333 V. Table 2-8. Excitation Level Jumper Selection Excitation Channel 0 Jumpers 3.
Chapter 2 Configuration and Installation Using the Internal Half-Bridge Completion Your SCXI-1121 includes half-bridge completion for half-bridge and quarter-bridge setups. The completion network consists of two 4.5 kΩ ± 0.05% ratio tolerance resistors with a temperature coefficient of 5 ppm/°C. These resistors are connected in series. To enable the network, you must set two jumpers for each input/excitation channel pair.
Chapter 2 Configuration and Installation Table 2-9.
Chapter 2 Configuration and Installation Hardware Installation You can install the SCXI-1121 in any available SCXI chassis. After you have made any necessary changes and have verified and recorded the jumper settings on the form in Appendix G, Technical Support Resources, you are ready to install the SCXI-1121. The following are general installation instructions consult the user manual or technical reference manual of your SCXI chassis for specific instructions and warnings. 1.
Chapter 2 Configuration and Installation Signal Connections This section describes the input and output signal connections to the SCXI-1121 board via the SCXI-1121 front connector and rear signal connector, and includes specifications and connection instructions for the signals given on the SCXI-1121 connectors. Cautions Do not operate the device in an explosive atmosphere or where there may be flammable gasses or fumes. Keep away from live circuits.
Chapter 2 Configuration and Installation When connecting or disconnecting signal lines to the SCXI terminal block screw terminals, make sure the lines are powered off. Potential differences between the lines and the SCXI ground create a shock hazard while you connect the lines. Connect the signal wires to the screw terminals by inserting the stripped end of the wire fully into the terminals. Tighten the terminals to a torque of 5 to 7 in.-lb.
Chapter 2 Pin Number Signal Name 32 A Column B Configuration and Installation C Signal Name CH0+ CH0– EX0+ EX0+ 31 30 29 28 EGND0 27 26 CH1+ CH1– EX1+ EX1– 25 24 23 22 EGND1 21 20 CH2+ CH2– EX2+ EX2– 19 18 17 16 EGND2 15 14 CH3+ CH3– EX3+ EX3– 13 12 11 10 EGND3 9 RSVD 8 7 6 SCAL RSVD 5 +5 V MTEMP CGND DTEMP 4 3 2 1 Figure 2-3.
Chapter 2 Configuration and Installation Front Connector Signal Descriptions Pin Signal Name Description A2 CGND Chassis Ground—This pin is tied to the SCXI chassis. C2 DTEMP Direct Temperature Sensor—This pin connects the temperature sensor to the MCH4+ when the terminal block is configured for direct temperature connection. A4 +5 V +5 VDC Source—This pin is used to power the temperature sensor on the terminal block. 0.2 mA of source not protected.
Chapter 2 Pin Signal Name Configuration and Installation Description A20 CH2+ Positive Input Channel 2—This pin is connected to the input channel 2 positive input. C20 CH2– Negative Input Channel 2—This pin is connected to the input channel 2 negative input. A22 EGND1 Excitation Ground 1—This pin connects to the excitation ground 1 via a 51 kΩ resistor. A24 EX1+ Positive Excitation Output 1—This pin is connected to the excitation channel 1 positive output.
Chapter 2 Configuration and Installation Analog Input Channels The positive input channels are located in column A. Their corresponding negative input channels are located in column C. Each input corresponds to a separate amplifier and is fully isolated from the other channels and from earth ground. The inputs are designed in a floating single-ended configuration, hence the measured signal can be referenced to a ground level with common-mode voltage up to 250 Vrms.
Chapter 2 Configuration and Installation + + + Vs Rbias – – Vout Module Figure 2-6. Floating AC-Coupled Signal Connection + Vs – + + Rbias – Vout Vcm + High – CMV Module Figure 2-7. AC-Coupled Signal Connection with High Common-Mode Voltage For AC-coupled signals, you should connect an external resistor from the positive input channel to the signal reference. This is needed to provide the DC path for the positive input bias current. Typical resistor values range from 100 kΩ to 1 MΩ.
Chapter 2 Configuration and Installation Exceeding the input signal range and the common-mode input range results in distorted signals. Exceeding the maximum input voltage rating (250 Vrms between positive and negative terminals and between any terminal and earth ground) can damage the SCXI-1121, the SCXIbus, and the DAQ board. National Instruments is not liable for any damages or injuries resulting from such signal connections.
Chapter 2 Configuration and Installation 3. Turn off your SCXI chassis. 4. Slide the selected module out of the SCXI chassis. 5. Remove the module cover. 6. Place one jack screw on the SCXI-1121 as indicated in Figure 2-8. 7. While holding the jack screw in place, insert the lock washer and then the nut. Notice that you might need long-nose pliers to insert the washer and nut. 8. Tighten the nut by holding it firmly and rotating the jack screw. 9.
Chapter 2 Configuration and Installation SCXI-1320, SCXI-1328, and SCXI-1321 Terminal Blocks The second type of connector available to connect the transducers to the SCXI-1121 inputs is a terminal block with an onboard temperature sensor and screw terminals for easy connection. One terminal block, the SCXI-1328 isothermal terminal block, has a high-accuracy onboard temperature sensor. The terminal block kits are listed in the Optional Equipment section in Chapter 1, Introduction.
Chapter 2 Configuration and Installation SCXI-1321 Offset-Null and Shunt-Calibration Terminal Block The SCXI-1321 terminal block operates only with Revision C and later SCXI-1121 modules. In addition to the 18 screw terminals, the SCXI-1321 has circuitry for offset-null adjust of Wheatstone bridges as well as a shunt resistor for strain-gauge shunt calibration. This terminal block works especially well with bridge-type transducers such as strain gauges.
Chapter 2 Configuration and Installation Table 2-11. Nulling Resistors and Corresponding Channel Channel Number Nulling Resistor 0 R3 1 R5 2 R7 3 R9 The value of all the nulling resistors on your terminal block is 39 kΩ. Notice that these resistors are socketed for easy replacement. These sockets best fit a 1/4 W resistor lead size.
Chapter 2 Configuration and Installation Assuming a strain-gauge range with a gauge factor of GF = 2 and a quarter-bridge configuration, this range corresponds to ±1,498 µε as given by the strain formula for a quarter-bridge strain-gauge configuration: –4V r ε = ------------------------------GF ( 1 + 2V r ) where strained voltage – static unstrained voltage V r = -------------------------------------------------------------------------------------------------------V exc EX+ Rnull Rg R Trimmer Potentio
Chapter 2 Configuration and Installation Table 2-12.
Chapter 2 Configuration and Installation EX+ SCAL RSCAL Rg R CH+ CH– SCXI-1321 R R EX– Figure 2-10. Shunt Circuit The shunting resistors RSCAL are socketed so that you can replace them with a resistor of another value to achieve the required changes. The RSCAL resistors on your terminal block have a 301 kΩ ±1% value. Assuming a quarter-bridge strain-gauge configuration with a gauge factor of GF = 2, the equivalent strain change introduced by the RSCAL shunting resistor is –199 µε.
Chapter 2 Configuration and Installation Terminal Block Temperature Sensor To accommodate thermocouples with the SCXI-1121, the terminal block has an onboard temperature sensor for cold-junction compensation. You can connect this temperature sensor in two ways: • You can connect the temperature sensor to the MTEMP pin (C4) on the module front connector and multiplex the sensor at the output multiplexer along with the amplifier outputs. This is the Multiplexed Temperature Sensor (MTS) mode.
Chapter 2 Configuration and Installation 1 T K = ------------------------------------------------------------3 [ a + b ( ln R T ) + c ( ln R T ) ] a = 1.288 x 10–3 b = 2.356 x 10–4 c = 9.556 x 10–8 RT = resistance of the thermistor in Ω V TEMPOUT R T = 50,000 -------------------------------------- 2.
Chapter 2 Configuration and Installation Tables 2-13, 2-14, and 2-15 show the jumper settings on the SCXI-1320, SCXI-1328, and SCXI-1321 terminal blocks. Table 2-13. Jumper Settings on the SCXI-1320 Terminal Block Jumper Position Description • • • DTEMP • • MTEMP MTEMP • W1 DTEMP DTS mode selected • • W1 MTS mode selected; factory setting; parking position Table 2-14.
Chapter 2 Configuration and Installation Terminal Block Signal Connection Warnings The chassis GND terminals on your terminal block are for grounding high impedance sources such as a floating source (1 mA maximum). Do not use these terminals as safety earth grounds. If high voltages (≥42 Vrms) are present, you must connect the safety earth ground to the strain-relief tab. This complies with UL 1244 and fully protects against electric shock when the terminal block is not connected to the chassis.
Chapter 2 Configuration and Installation Figure 2-11. SCXI-1320 Parts Locator Diagram SCXI-1121 User Manual 2-34 www.natinst.
Chapter 2 Configuration and Installation Figure 2-12.
Chapter 2 Configuration and Installation Figure 2-13. SCXI-1321 Parts Locator Diagram Terminal Block Installation To connect the terminal block to the SCXI-1121 front connector, perform the following steps: SCXI-1121 User Manual 1. Connect the SCXI-1121 front connector to its mating connector on the terminal block. 2. Make sure that the SCXI-1121 top and bottom thumbscrews do not obstruct the rear panel of the terminal block. 3.
Chapter 2 Configuration and Installation Rear Signal Connector Note If you are using the SCXI-1121 with a National Instruments data acquisition board and cable assembly, you do not need to read the remainder of this chapter. If you are using the SCXI-1180 feedthrough panel, the SCXI-1343 rear screw terminal adapter, or the SCXI-1351 one-slot cable extender with the SCXI-1121, you should read this section. Figure 2-14 shows the pin assignments for the SCXI-1121 rear signal connector.
Chapter 2 Configuration and Installation Rear Signal Connector Signal Descriptions Pin Signal Name Description 1-2 AOGND Analog Output Ground—These pins are connected to the analog reference when jumper W33 is in position AB-R0. 3-12 MCH0± through MCH4± Analog Output Channels 0 through 4—Connects to the data acquisition board differential analog input channels.
Chapter 2 Configuration and Installation The signals on the rear signal connector can be classified as analog output signals, digital I/O signals, or timing I/O signals. Signal connection guidelines for each of these groups are given in the following section. Analog Output Signal Connections Pins 1 through 12 and pin 19 of the rear signal connector are analog output signal pins. Pins 1 and 2 are AOGND signal pins.
Chapter 2 Configuration and Installation Digital I/O Signal Connections Pins 24 through 27, 29, 33, 36, 37, and 43 constitute the digital I/O lines of the rear signal connector. They are divided into three categories—the digital input signals, the digital output signals, and the digital timing signals. The digital input signals are pins 24, 25, 27, 29, 33, and 37. The data acquisition board uses these pins to configure an SCXI module that is under data acquisition board control.
Chapter 2 Configuration and Installation Table 2-16. SCXIbus to SCXI-1121 Rear Signal Connector to Data Acquisition Board Pin Equivalences SCXIbus Line SCXI-1121 Rear Signal Connector MIO-16 Lab-NB/Lab-PC Lab-PC+/Lab-LC PC-LPM-16 MOSI SERDATIN ADIO0 PB4 DOUT4 D*/A DAQD*/A ADIO1 PB5 DOUT5 INTR* SLOT0SEL* ADIO2 PB6 DOUT6 SPICLK SERCLK EXTSTROBE* PB7 DOUT7 MISO SERDATOUT BDIO0 PC1 DIN6 The digital timing signals are pins 36 and 43.
Chapter 2 Configuration and Installation Timing Requirements and Communication Protocol Timing Signal The data acquisition timing signal is SCANCLK. SCANCLK is used to increment MUXCOUNTER on its rising edge. Figure 2-15 shows the timing requirements of the SCANCLK signal. These requirements will ensure that SCANCLK is properly transmitted over TRIG0. Thigh SCANCLK Tlow Thigh Tlow Time low before rising edge Time high before falling edge 400 nsec minimum 250 nsec minimum Figure 2-15.
Chapter 2 Configuration and Installation SLOT0SEL* SS*X Chassis Y SS*11 Chassis 9 Tss_dis Tclk_wait Tss_en SERCLK Tslot0sel*_wait SERDATIN 0 1 0 0 1 1 0 Chassis ID = 9 Tss _ dis Tclk _ wait Tslot0sel* _ wait Tss _ en SLOT0SEL* low to SS* disabled SLOT0SEL* low to first rising edge on SERCLK Last rising edge on SERCLK to SLOT0SEL* high SLOT0SEL* high to SS* enabled 1 1 Slot 11 200 nsec maximum 75 nsec minimum 250 nsec minimum 350 nsec maximum Figure 2-16.
Chapter 2 Configuration and Installation Figure 2-17 shows the timing requirements on the SERCLK and SERDATIN signals. You must observe these timing requirements for all communications. Tdelay is a specification of the SCXI-1121.
Chapter 2 Configuration and Installation 3. Pull SLOT0SEL* low to deassert the SS* line and establish conditions for writing a new slot-select number to the Slot 0 Slot-Select Register. 4. If you are not selecting another slot, you should write zero to the Slot 0 Slot-Select Register. Figure 2-18 illustrates a write to the SCXI-1121 Configuration Register of the binary pattern: 10000011 00001111 SLOT0SEL* SS* SERCLK SERDATIN 1 0 0 0 0 0 1 1 0 0 0 0 1 1 1 1 Figure 2-18.
Chapter 2 Configuration and Installation Figure 2-19 illustrates a read of the SCXI-1121 Module ID Register. SLOT0SEL* SS* SERCLK SERDATOUT Tdelay 0 0 0 0 00 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 byte 0 = 2 Tdelay byte 1 = 0 byte 2 = 0 SS* high to SERDATOUT high byte 3 = 0 350 nsec maximum Figure 2-19. SCXI-1121 Module ID Register Timing Diagram For further details on programming these signals, refer to Chapter 5, Programming. SCXI-1121 User Manual 2-46 www.natinst.
3 Theory of Operation This chapter contains a functional overview of the SCXI-1121 module and explains the operation of each functional unit making up the SCXI-1121. Functional Overview The block diagram in Figure 3-1 illustrates the key functional components of the SCXI-1121.
Chapter 3 Theory of Operation The major components of the SCXI-1121 are as follows: • SCXIbus connector • Digital interface • Digital control circuitry • Timing and analog circuitry The SCXI-1121 consists of four isolated amplifier channels with gains of 1, 2, 5, 10, 20, 50, 100, 200, 500, 1,000, and 2,000, and four isolated excitation channels with voltage or current excitation.
Chapter 3 Theory of Operation SCXIbus Connector Figure 3-2 shows the pin assignments for the SCXIbus connector.
Chapter 3 Theory of Operation SCXIbus Connector Signal Descriptions Pin Signal Name Description A1, B1, C1, D1, A2, D2,A3, B3, C3, D3, A4, D4, A5, B5, C5, D5, A6, D6 GUARD Guard—Shields and guards the analog bus lines from noise. B2 AB0+ Analog Bus 0+ —Positive analog bus 0 line. Used to multiplex several modules to one analog signal. C2 AB0– Analog Bus 0– —Negative analog bus 0 line. Used to multiplex several modules to one analog signal.
Chapter 3 Pin Signal Name Theory of Operation Description A24 TRIG0 TRIG0—General-purpose trigger line used by the SCXI-1121 to send SCANCLK to other modules or receive SCANCLK from other modules. Open collector. I/O. B24 SS* Slot Select—When low, enables module communications over the SCXIbus. Totem pole. Input. C24 SCANCON Scanning Control—Combination output enable and reload signal for scanning operations. Totem pole. Input. All other pins are not connected.
Chapter 3 Theory of Operation chassis is being used), and then releasing INTR* high. At this point, SS* of the desired slot is asserted low and the data acquisition board can communicate with the module in that slot according to the SPI protocol. Digital Interface Figure 3-3 shows a diagram of the SCXI-1121 and SCXIbus digital interface circuitry.
Chapter 3 Theory of Operation Digital Control Circuitry Figure 3-4 diagrams the SCXI-1121 digital control. Serial Data Out Module ID Register Buffered Serial Data In Input Channel Select Configuration Register Output Stage Control Buffered Digital Control Signals SCANCLK Path Control Hardware Scan Control Figure 3-4. SCXI-1121 Digital Control The digital control section consists of the Configuration Register and the Module ID Register.
Chapter 3 Theory of Operation 3. The serial data is available on MOSI and SPICLK clocks it into the register. 4. SS* goes high and D*/A goes high, indicating an end of communication. This action latches the Configuration Register bits. When the SCXIbus is reset, all bits in the Configuration Register are cleared. The Module ID Register connects to MISO on the SCXIbus. The Module ID Register is an 8-bit parallel/serial-in serial-out shift register and an SPI communication adapter.
Chapter 3 Theory of Operation Input Channel 0 + + LPF LPF + – To Output Stage LPF + – To Output Stage LPF + – To Output Stage LPF + – To Output Stage – I + EX0 – Input Channel 1 + – + LPF I + EX1 – Input Channel 2 + – + LPF I + EX2 – Input Channel 3 + – + LPF I + EX3 – MTEMP DTEMP Figure 3-5.
Chapter 3 Theory of Operation The analog input consists of four isolated single-ended noninverting amplifiers. In addition, lowpass filtering is available at the inputs. You can jumper select one of two bandwidths, 10 kHz or 4 Hz. The amplifier gain is divided into two stages, a first stage providing gains of 1, 10, 50, and 100, and a second stage providing gains of 1, 2, 5, 10, and 20. Also, the module has an internal completion network that can be used with half-bridge or quarter-bridge networks.
Chapter 3 Theory of Operation After isolation, further filtering is available to increase the noise immunity of the amplifier channel. It is important to note that the overall amplifier bandwidth is determined by both filtering stages, so to achieve the required bandwidth, both filtering sections should be set the same, as indicated in Chapter 2, Configuration and Installation.
Chapter 3 Theory of Operation • • You also need a 120 Ω 1/4 W precision resistor with tempco less than or equal to 5 ppm, or an ammeter with the following specifications: – Accuracy: ±0.004% standard ±0.016% sufficient – Range: 0.5 mA – Resolution: 6 1/2 digits If you use the resistor to calibrate the current excitation, you also need an ohmmeter with four-wire measurement and the following specifications: – Accuracy: ±0.004% standard ±0.
Chapter 3 Theory of Operation 8. Adjust the input potentiometer of the channel of interest until the output is 0 ± 6 mV. 9. Go to the next channel. To avoid erroneous results when nulling the amplifier, follow these steps in the order indicated. Excitation Adjust When calibrating the excitation channels, you should always start with the voltage excitation and then proceed to the current excitation, because the voltage excitation reference is used as a voltage reference for the current excitation.
Chapter 3 Theory of Operation This procedure calibrates the 10 V and 450 µA levels at the same time but the accuracy achieved is limited to ±0.2%. To achieve better accuracies at these levels, follow the procedure indicated above but set the excitation levels to 10 V and to 450 µA instead of 3.333 V and 150 µA. If you do so, the lower excitation levels of this channel will then be calibrated to ±0.2% instead of to 0.04%. In the factory, the module is calibrated for 3.333 V and 150 µA.
Chapter 3 Theory of Operation Analog Output Circuitry Figure 3-6 shows the SCXI-1121 analog output circuitry. SCXIbus Output Stage Control AB0 Switch Output Mux Buffer MCH0+ MCH0– MTEMP From MCH1+ Channel 1 MCH1– Output Stage and Hardware Scan Control From MCH2+ Channel 2 MCH2– Analog Reference Rear Signal Connector Channel 0 Channel 1 Channel 2 Channel 3 From MCH3+ Channel 3 MCH3– DTEMP MCH4+ MCH4– Figure 3-6.
Chapter 3 Theory of Operation in the Configuration Register when SCANCON is high (inactive) and will count upwards on each rising clock edge when SCANCON is low (active). In the Parallel-Output Mode, the MUXCOUNTER is disabled and its output indicates binary 00 hence, amplifier channel 0 is selected at the output multiplexer and is connected to MCH0. The three other channels are hardwired to MCH1 through MCH3 on the rear signal connector.
Chapter 3 Theory of Operation Scanning Modes There are four basic types of scanning modes possible with the SCXI-1121—single-module parallel scanning, single-module multiplexed scanning, multiple-module multiplexed scanning, and multiple-chassis scanning (possible only with the SCXI-1001 chassis). For additional information, consult Chapter 2, Configuration and Installation, Chapter 5, Programming, your data acquisition board manual, and your SCXI chassis user manual.
Chapter 3 Theory of Operation entry. The list in Slot 0 will determine which module is being accessed and for how many samples. It is important that you make sure that the lists on the data acquisition board and Slot 0 are compatible so that the samples are acquired as intended. See your SCXI chassis manual for more information. Single-Module Multiplexed Scanning Single-Module Multiplexed Scanning (Direct) This is the simplest multiplexed scanning mode.
Chapter 3 Theory of Operation SCXI-1000 or SCXI-1001 Chassis SCANCON X TRIG0 Data Acquisition Board SCANCLK MCH0 Timing Output Analog Input Other Module SLOT 0 SCXI-1121 SLOT X Cable Assembly Analog Bus 0 Figure 3-9. Single-Module Multiplexed Scanning (Indirect) Multiple-Module Multiplexed Scanning In this mode, all the modules tie into Analog Bus 0, and SCANCON enables the output of their amplifiers.
Chapter 3 Theory of Operation Multiple-Chassis Scanning In this mode, you attach each SCXI-1001 chassis to a daisy chain of cable assemblies and multichassis adapter boards, as illustrated in Figure 3-11. You program each chassis separately, and each chassis occupies a dedicated channel of the data acquisition board. Within each chassis, scanning operations act as if the other chassis are not being used, with one exception.
Register Descriptions 4 This chapter describes in detail the SCXI-1121 Module ID Register, the Configuration Register, the Slot 0 registers, and multiplexer addressing. Note If you plan to use a programming software package such as NI-DAQ, LabWindows, or LabVIEW with your SCXI-1121 board, you do not need to read this chapter. Register Description Register Description Format The register description chapter discusses each of the SCXI-1121 registers and the Slot 0 registers.
Chapter 4 Register Descriptions Module ID Register The Module ID Register contains the 4-byte module ID code for the SCXI-1121. This code number will be read as the first four bytes on the MISO line whenever the module is accessed. The bytes will appear least significant byte first. Within each byte, data is sent out most significant bit first. Additional data transfers will result in all zeros being sent on the MISO line.
Chapter 4 Register Descriptions Configuration Register The Configuration Register contains 16 bits that control the functions of the SCXI-1121. When SS* is asserted (low) and D*/A indicates data (low), the register will shift in the data present on the MOSI line, bit 15 first, and then latch it when the SCXI-1121 is deselected by the SS* signal on the backplane. The Configuration Register initializes to all zeros when the SCXI chassis is reset or first turned on.
Chapter 4 Register Descriptions 9-8 CHAN<1..0> Channel Select—These bits determine the channel number (zero to three) that is loaded into the MUXCOUNTER to determine the analog channel to be read during a single read, or the starting channel on the module for a scanned data acquisition. CHAN1 is the MSB. 5 RTEMP Read Temperature—This bit determines whether the selected channel output or the MTEMP signal is driven onto the MCH0± pins of the rear signal connector.
Chapter 4 0 FOUTEN* Register Descriptions Forced Output Enable—This bit determines whether the module will drive the MCH0± pins on the rear signal connector with either the selected channel output or the MTEMP signal, depending on the state of RTEMP. If FOUTEN* is cleared to zero, the MCH0± pins will be driven through a buffer by the selected channel output or the MTEMP line.
Chapter 4 Register Descriptions Slot-Select Register The Slot-Select Register contains 16 bits that determine which module in which chassis will be enabled for communication when the SLOT0SEL* line is set to one. An SCXI-1000 chassis will select the appropriate module in its chassis, regardless of the chassis number written. The Slot-Select Register will shift in the data present on the MOSI line, bit 16 first, when SLOT0SEL* is cleared to zero.
Chapter 4 Register Descriptions Hardscan Control Register (HSCR) The HSCR contains eight bits that control the setup and operation of the hardscan timing circuitry of Slot 0. To write to the HSCR, follow the procedure given in the Register Writes section of Chapter 5, Programming, using 13 as the slot number, and writing eight bits to the HSCR. The register will shift in the data present on the MOSI line, bit seven first, when Slot 13 is selected by the Slot-Select Register.
Chapter 4 Register Descriptions 1 SCANCONEN Scan Control Enable—When set, this bit enables the SCANCON lines. When clear, all SCANCON lines are disabled (high). 0 CLKEN SCXI-1121 User Manual Clock Enable—When set, this bit enables TRIG0 as a clock for the hardscan circuitry. When clear, TRIG0 is disabled. 4-8 www.natinst.
Chapter 4 Register Descriptions FIFO Register The FIFO Register is used to add entries to the Slot 0 FIFO. The FIFO contains the Slot 0 scan list. Each entry contains a slot number to be accessed, and a count number to determine the number of samples to be taken from that slot. To write to the FIFO Register, follow the procedure given in the Register Writes section of Chapter 5, Programming, using 14 as the slot number, and writing 16 bits to the FIFO Register.
5 Programming This chapter contains a functional programming description of the SCXI-1121 and Slot 0. Note If you plan to use a programming software package such as NI-DAQ, LabWindows, or LabVIEW with your SCXI-1121 board, you do not need to read this chapter. Programming Considerations Programming the SCXI-1121 involves writing to the Configuration Register. Programming Slot 0 involves writing to the HSCR and FIFO Register. Programming the data acquisition boards involves writes to their registers.
Chapter 5 Programming Register Writes This section describes how to write to the Configuration Register, HSCR, and FIFO Register including the procedure for writing to the Slot-Select Register to select the appropriate slot. For timing specifics, refer to the Timing Requirements and Communication Protocol section in Chapter 2, Configuration and Installation. The rear signal connector pin equivalences to the different National Instruments data acquisition boards are given in Table 5-1.
Chapter 5 3. Programming For each bit, starting with the MSB first (bit 15): a. SERDATIN = bit to be sent. These bits are the data that is being written to the Slot-Select Register. b. Clear SERCLK to 0. c. Set SERCLK to 1. This rising edge clocks the data. (If you are using an MIO-16 board, writing to the EXTSTROBE* register will pulse EXTSTROBE* low and then high, accomplishing steps 3b and 3c.) 4. Set SLOT0SEL* to 1.
Chapter 5 Programming to MCH0 through MCH3 on the rear signal connector. The module is disconnected from Analog Bus 0 and disabled from scanning. Single-Channel Measurements This section describes how to program the SCXI-1121, either alone or in conjunction with other modules, to make single-channel, or nonscanned, measurements.
Chapter 5 Programming To measure one of the four differential input channels to the SCXI-1121, perform the following steps: 1. Write the binary pattern 000XXXCC XX000000 to the SCXI-1121 Configuration Register. 2. Measure the voltage with the data acquisition board. To shunt calibrate one of the four differential input channels, perform the following steps: 1. Write the binary pattern 001XXXCC XX00000 to the SCXI-1121 Configuration Register.
Chapter 5 Programming Measurements from the SCXI-1121 via Another Module To perform measurements via another module, you must cable the other module rear signal connector to a data acquisition board. The other module must also be able to transfer Analog Bus 0 to the data acquisition board. See Chapter 2, Configuration and Installation, for more information. To measure one of the four differential input channels to the SCXI-1121, perform the following steps: 1.
Chapter 5 Programming Scanning Measurements Programming for scanned data acquisition involves programming your data acquisition board, modules, and Slot 0. In general, the steps to be taken are as follows: 1. Perform all data acquisition board programming to the point of enabling the data acquisition. 2. Perform all module programming. 3. Program the Slot 0 hardscan circuitry. 4. Enable the data acquisition, trigger it either through software or hardware, and service the data acquisition.
Chapter 5 Programming • • • AT-MIO-16X User Manual – Continuous Channel Scanning Data Acquisition – Interval Channel Scanning Data Acquisition AT-MIO-64F-5 User Manual – Continuous Channel Scanning Data Acquisition – Interval Channel Scanning Data Acquisition Lab-LC User Manual – • Lab-NB User Manual – • • • • – Programming Multiple A/D Conversions with Channel Scanning – Programming Multiple A/D Conversions with Interval Scanning – Programming Multiple A/D Conversions in Single-Cha
Chapter 5 Programming Follow the instructions in these sections through the part labeled as follows: • Clear the A/D Circuitry and Reset the Mux Counter in the MIO board user manual (except for the AT-MIO-16X and the AT-MIO-64F-5). Do not continue to the part called Enable the Scanning Data Acquisition Operation. You will do this after you program the modules and Slot 0.
Chapter 5 Programming To program the MIO board to take N samples per data acquisition board scan list entry, perform the following additional programming steps at the end of the Enable the Scanning Data Acquisition Operation section in the appropriate data acquisition board user manual: 1. Write FF01 to the Am9513 Command Register to select Counter 1 Mode Register. 2. Write 0325 (hex) to the Am9513 Data Register to store Counter 1 Mode Value for most MIO boards.
Chapter 5 Programming Single-Module Multiplexed Scanning (Direct) To perform simple channel scanning, you must cable the SCXI-1121 to a data acquisition board. See Chapter 2, Configuration and Installation, for more information. To program the module for scanned channel measurements, write the binary pattern 10ScXXXCC XX001101 to the SCXI-1121 Configuration Register. CC represents the starting channel number.
Chapter 5 Programming 2. Program the other module not to drive Analog Bus 0, but to send Analog Bus 0 to the data acquisition board. Also program the other module to send a SCANCLK*-compatible signal to TRIG0. 3. Write the binary pattern 01ScXXXCC XX001111 to the SCXI-1121 Configuration Register, where CC is the starting channel number.
Chapter 5 Programming channel. See the Counter 1 and SCANDIV subsection of the 1. Data Acquisition Board Setup Programming section earlier in this chapter. You can use the MIO-16 boards in conjunction with the SCXI-1350 multichassis adapter for multichassis scanning. For each chassis, program the modules according to the appropriate mode of operation, disregarding the fact that other chassis will be involved. For example, you want to scan thirteen modules. Twelve modules are in one chassis.
Chapter 5 Programming 5. Write binary 101S 1100 to the HSCR. 6. Write binary 101S 1110 to the HSCR. 7. Write binary 101S 1111 to the HSCR. In the preceding steps, S = 0 if you want the scanning to repeat when the end of the list is reached. S = 1 if you want the circuitry to shut down after a single scan.
Chapter 5 • Programming Lab-NB User Manual – Program the sample-interval counter (Counter A0) – Service the data acquisition operation. Scanning Examples The following examples are intended to aid your understanding of module and Slot 0 programming. It will be helpful to refer to the bit descriptions for the Configuration Register and the FIFO Register at the beginning of Chapter 4, Register Descriptions.
Chapter 5 Programming 2. Following the procedure given in the Register Writes section, write 00000000 00000000 to the Configuration Register of the SCXI-1121 in Slot 2. This step resets the module, including the clearing of the AB0EN bit (bit 0). Notice that a complete reset of this module is not necessary, but is used for simplicity. 3. Following the procedure given in the Register Writes section, write 100XXX00 00001111 to the Configuration Register of the SCXI-1121 in Slot 4. 4.
Chapter 5 Programming Assuming that the modules are cabled and programmed correctly, the Slot 0 scan lists should be as follows: Chassis 1 Chassis 2 Chassis 3 Entry Slot Number Count Entry Slot Number Count Entry Slot Number Count 1 4 4 1 13 4 1 13 6 2 13 6 2 11 2 2 3 1 3 13 4 3 8 3 Other solutions are possible. In the section, 3. Programming the Slot 0 Hardscan Circuitry, earlier in this chapter, step 3 consists of the following steps: 1. Select Slot 14 in Chassis 1.
A Specifications This appendix lists the specifications for the SCXI-1121. These are typical at 25 °C unless otherwise stated. The operating temperature range is 0 to 50 °C. Analog Input Gain (jumper-selectable)........................ 1, 2, 5, 10, 20, 50, 100, 200, 500, 1,000, 2,000 Output range........................................... ±5 V Number of channels ............................... 4 Gain accuracy1 ...................................... 0.15% of full scale Offset voltage Input ...............
Appendix A Specifications Filtering (jumper-selectable) ..................4 Hz (–10 dB) or 10 kHz (–3 dB), 3-pole RC Noise (400 kHz bandwidth)1 Input (gain = 1,000) 4 Hz filter .................................100 nVrms 10 kHz filter .............................4 µVrms Output (gain = 1) 4 Hz ..........................................150 µVrms 10 kHz ......................................1 mVrms Output selection time (with 5 V step, all gains)2 0.012% accuracy..............................5.
Appendix A Specifications RTD Mode Excitation current ................................... 0.15 mA ±0.04%, 0.45 mA ±0.2% Maximum load resistance ...................... 10 kΩ Drift ........................................................ 40 ppm/ °C Lead resistance effect............................. Negligible (4-wire measurement) Resistance range..................................... 10 kΩ, maximum Strain Gauge Mode Bridge types ...........................................
Appendix A Specifications Note You can find the temperature T (°C) as follows: T = TK – 273.15 where TK is the temperature in kelvin 1 T K = ------------------------------------------------------------3 [ a + b ( ln R T ) + c ( ln R T ) ] a = 1.288 x 10–3 b = 2.356 x 10–4 c = 9.556 x 10–8 RT = resistance of the thermistor in Ω V TEMPOUT R T = 50000 -------------------------------------- 2.5 – V TEMPOUT VTEMPOUT = output voltage of the temperature sensor Physical Dimensions ........................
B Rear Signal Connector This appendix describes the pinout and signal names for the SCXI-1121 50-pin rear signal connector, including a description of each connection. Figure B-1 shows the pin assignments for the SCXI-1121 rear signal connector.
Appendix B Rear Signal Connector Rear Signal Connector Signal Descriptions Pin Signal Name Description 1-2 AOGND Analog Output Ground—These pins are connected to the analog reference when jumper W33 is in position AB-R0. 3-12 MCH0± through MCH4± Analog Output Channels 0 through 4—Connects to the data acquisition board differential analog input channels. 19 OUTREF Output Reference—This pin serves as the reference node for the analog channels output in the Pseudodifferential Reference mode.
C SCXIbus Connector This appendix describes the pinout and signal names for the SCXI-1121 96-pin SCXIbus connector, including a description of each connection.
Appendix C SCXIbus Connector Figure C-1 shows the pin assignments for the SCXI-1121 SCXIbus connector.
Appendix C SCXIbus Connector SCXIbus Connector Signal Descriptions Pin Signal Name Description A1, B1, C1, D1, A2, D2,A3, B3, C3, D3, A4, D4, A5, B5, C5, D5, A6, D6 GUARD Guard—Shields and guards the analog bus lines from noise. B2 AB0+ Analog Bus 0+ —Positive analog bus 0 line. Used to multiplex several modules to one analog signal. C2 AB0– Analog Bus 0– —Negative analog bus 0 line. Used to multiplex several modules to one analog signal.
Appendix C SCXIbus Connector Pin Signal Name Description A24 TRIG0 TRIG0—General-purpose trigger line used by the SCXI-1121 to send SCANCLK to other modules or receive SCANCLK from other modules. Open collector. I/O. B24 SS* Slot Select—When low, enables module communications over the SCXIbus. Totem pole. Input. C24 SCANCON Scanning Control—Combination output enable and reload signal for scanning operations. Totem pole. Input. All other pins are not connected.
SCXI-1121 Front Connector D This appendix describes the pinout and signal names for the SCXI-1121 front connector, including a description of each connection.
Appendix D SCXI-1121 Front Connector Figure D-1 shows the pin assignments for the SCXI-1121 front connector. Pin Number Signal Name 32 A Column B C Signal Name CH0+ CH0 EX0+ EX0+ 31 30 29 EGND0 28 27 26 CH1+ CH1 EX1+ EX1– 25 24 23 EGND1 22 21 20 CH2+ CH2- EX2+ EX2– 19 18 17 EGND2 16 15 14 CH3+ CH3– EX3+ EX3– 13 12 11 EGND3 10 9 RSVD 8 7 SCAL 6 RSVD 5 4 +5 V MTEMP CGND DTEMP 3 2 1 Figure D-1. SCXI-1121 Front Connector Pin Assignment SCXI-1121 User Manual D-2 www.
Appendix D SCXI-1121 Front Connector Front Connector Signal Descriptions Pin Signal Name Description A2 CGND Chassis Ground—This pin is tied to the SCXI chassis. C2 DTEMP Direct Temperature Sensor—This pin connects the temperature sensor to the MCH4+ when the terminal block is configured for direct temperature connection. A4 +5 V +5 VDC Source—This pin is used to power the temperature sensor on the terminal block. 0.2 mA of source not protected.
Appendix D SCXI-1121 Front Connector Signal Name Pin Description C18 EX2– Negative Excitation Output 2—This pin is connected to the excitation channel 2 negative output. A20 CH2+ Positive Input Channel 2—This pin is connected to the input channel 2 positive input. C20 CH2– Negative Input Channel 2—This pin is connected to the input channel 2 negative input. A22 EGND1 Excitation Ground 1—This pin connects to the excitation ground 1 via a 51 kΩ resistor.
E SCXI-1121 Cabling This appendix describes how to use and install the hardware accessories for the SCXI-1121: • SCXI-1340 cable assembly • SCXI-1341 Lab-NB, Lab-PC, and Lab-PC+ cable assembly • SCXI-1344 Lab-LC cable assembly • SCXI-1342 PC-LPM-16 cable assembly • SCXI-1180 feedthrough panel • SCXI-1302 50-pin terminal block • SCXI-1351 one-slot cable extender • SCXI-1350 multichassis adapter • SCXI-1343 screw terminal adapter SCXI-1340 Cable Assembly The SCXI-1340 cable assembly connec
Appendix E SCXI-1121 Cabling You can use a standard 50-pin ribbon cable instead of the SCXI-1340 cable assembly. The SCXI-1340 has the following advantages over the ribbon cable: • The SCXI-1340 has strain relief so that you cannot accidentally disconnect the cable. • The SCXI-1340 includes a mounting bracket that mounts to the chassis so that you can remove and reinsert the module without explicitly removing the cable from the back of the chassis.
Appendix E SCXI-1121 Cabling Table E-1. SCXI-1121 and MIO-16 Pinout Equivalences (Continued) SCXI-1121 Rear Signal Connector Pin MIO-16 Equivalent 25 SERDATIN ADIO0 26 SERDATOUT BDIO0 27 DAQD*/A ADIO1 29 SLOT0SEL* ADIO2 36 SCANCLK SCANCLK 37 SERCLK EXTSTROBE* 43 RSVD OUT1 No other pins are connected on the SCXI-1121. SCXI-1340 Installation Follow these steps to install the SCXI-1340: 1. Make sure that the computer and the SCXI chassis are turned off. 2.
Appendix E SCXI-1121 Cabling Mounting Bracket Connector Rear Panel Step 4 Step 5 50-Pin Female Connector to MIO-16 Board Step 3 Step 4 SCXI-1121 Rear Signal Connector Male Breakout Connector Mounting Bracket Figure E-1. SCXI-1340 Installation SCXI-1341 Lab-NB, Lab-PC, or Lab-PC+ and SCXI-1344 Lab-LC Cable Assembly The SCXI-1341 Lab-NB, Lab-PC, or Lab-PC+ cable assembly connects a Lab-NB, Lab-PC, or Lab-PC+ board to an SCXI-1121 module.
Appendix E SCXI-1121 Cabling jumper W1. Table E-2 lists the SCXI-1341 and SCXI-1344 pin translations. Note If you are using the Lab-PC+, configure the board for single-ended inputs. Table E-2.
Appendix E SCXI-1121 Cabling All other pins of the Lab board pinout are not sent to the SCXI-1121 rear signal connector. SCXI-1341 and SCXI-1344 Installation Follow these steps to install the SCXI-1341 or SCXI-1344: 1. Make sure that the computer and the SCXI chassis are turned off. 2. Install the SCXI module in the chassis. 3. Connect one end of the ribbon cable to the adapter board rear connector. This is the 50-pin connector of the SCXI-1344 cable. 4.
Appendix E SCXI-1121 Cabling Table E-3.
Appendix E SCXI-1121 Cabling All other pins of the PC-LPM-16 pinout are not sent to the SCXI-1121 rear signal connector. SCXI-1342 Installation Follow these steps to install the SCXI-1342: 1. Make sure that the computer and the SCXI chassis are turned off. 2. Install the SCXI module to which the SCXI-1342 will connect. 3. Connect one end of the ribbon cable to the adapter board rear connector. 4. Plug the adapter board front connector onto the module rear signal connector.
Appendix E SCXI-1121 Cabling SCXI-1180 Installation Install the SCXI-1180 to the right of a slot that has an SCXI-1340, SCXI-1341, SCXI-1342, or SCXI-1344 cable assembly or an SCXI-1351 slot extender in its rear connector space. Follow these steps to install the SCXI-1180: 1. Make sure that the computer and the SCXI chassis are turned off. 2. Remove the front filler panel of the slot where you will insert the SCXI-1180. 3.
Appendix E SCXI-1121 Cabling Front Panel Connector Ribbon Cable to Rear and Breakout Connectors Step 5 Front Panel Front Threaded Strip Figure E-3. SCXI-1180 Front Panel Installation SCXI-1302 50-Pin Terminal Block The SCXI-1302 terminal block has screw terminal connections for the 50-pin connector on the SCXI-1180 feedthrough panel. SCXI-1302 Wiring Procedure To wire the SCXI-1302 terminal block, you must remove the cover, connect all the wiring, and replace the cover.
Appendix E SCXI-1121 Cabling 6. Snap the cover back in place. 7. Reinsert the rear grounding screw. The terminal block is now ready to be connected to the front panel connector. 50-Pin Connector Grounding Screw Step 2 Step 1 Insert Screwdriver in Groove and Rotate to Pry Open Thumbscrew Cutout Figure E-4. Cover Removal SCXI-1302 Installation Follow these steps to install the SCXI-1302: 1. Install an SCXI-1180 feedthrough panel as described in the SCXI-1180 Installation section. 2.
Appendix E SCXI-1121 Cabling SCXI-1351 One-Slot Cable Extender The SCXI-1351 cable extender is a miniature SCXI-1340 cable assembly. Instead of connecting to an MIO board 1 m away, the SCXI-1351 female rear connector connects to the male breakout connector of a module that must be in the rear connector space of the slot to the left.
Appendix E SCXI-1121 Cabling The adapter board has a male rear connector, a female front connector, and a male chassis extender connector. You can attach the rear connector to a ribbon cable from the MIO board or a preceding chassis. You connect the front connector with the module rear signal connector. You connect the chassis extender connector to a ribbon cable that goes to the subsequent chassis. The adapter takes Channel 0 from the front connector and sends it to Channel 0 of the rear connector.
Appendix E SCXI-1121 Cabling SCXI-1343 Rear Screw Terminal Adapter You use the SCXI-1343 universal adapter to adapt custom wiring to the SCXI-1121. The SCXI-1343 has screw terminals for the analog output connections and solder pads for the rest of the signals. A strain-relief clamp is on the outside of the rear panel. Table E-4 shows the SCXI-1343 pin connections. SCXI-1343 Installation Follow these steps to install the SCXI-1343: 1. Insert each wire through the adapter strain-relief opening. 2.
Appendix E SCXI-1121 Cabling Table E-4.
Appendix E SCXI-1121 Cabling Table E-4. SCXI-1343 Pin Connections (Continued) SCXI-1121 User Manual Rear Signal Connector Pin SCXI-1121 Use Connection Type 39 No Connect Solder pad 40 No Connect Solder pad 41 No Connect Solder pad 42 No Connect Solder pad 43 RSVD Solder pad 44 No Connect Solder pad 45 No Connect Solder pad 46 No Connect Solder pad 47 No Connect Solder pad 48 No Connect Solder pad 49 No Connect Solder pad 50 No Connect Solder pad E-16 www.natinst.
Revision A and B Photo and Parts Locator Diagrams F This appendix contains a photograph of the Revision A and B SCXI-1121 signal conditioning module and the general and detailed parts locator diagrams. Figure F-1 shows the SCXI-1121 module. Figures F-2 and F-3 show the general and detailed parts locator diagrams of the Revision A and B SCXI-1121. Figure F-1.
Appendix F F-2 Revision A and B Photo and Parts Locator Diagrams SCXI-1121 User Manual www.natinst.com Figure F-2.
© National Instruments Corporation Appendix F F-3 Revision A and B Photo and Parts Locator Diagrams SCXI-1121 User Manual Figure F-3.
Technical Support Resources G This appendix describes the comprehensive resources available to you in the Technical Support section of the National Instruments Web site and provides technical support telephone numbers for you to use if you have trouble connecting to our Web site or if you do not have internet access. NI Web Support To provide you with immediate answers and solutions 24 hours a day, 365 days a year, National Instruments maintains extensive online technical support resources.
Appendix G Technical Support Resources Software-Related Resources • Instrument Driver Network—A library with hundreds of instrument drivers for control of standalone instruments via GPIB, VXI, or serial interfaces. You also can submit a request for a particular instrument driver if it does not already appear in the library. • Example Programs Database—A database with numerous, non-shipping example programs for National Instruments programming environments.
Glossary Prefix Meaning Value p- pico- 10 –12 n- nano- 10 –9 µ- micro- 10 – 6 m- milli- 10 –3 k- kilo- 10 3 M- mega- 10 6 Numbers/Symbols ° degrees Ω ohms ε strain +5 V (signal) +5 VDC source signal A A amperes AB0+ positive analog bus 0 line signal AB0– negative analog bus 0 line signal AB0EN analog bus 0 enable bit AB2+ positive analog bus 2 line signal AB2– negative analog bus 2 line signal ACH# data acquisition board analog input channel number A/D analog-to-d
Glossary AOGND analog output ground signal Arms amperes, root mean square AWG American Wire Gauge B BW bandwidth C C Celsius CH#+ positive input channel number signal CH#– negative input channel number signal CHAN channel select bit CHS chassis bit CHSGND chassis ground signal CJR cold-junction reference CLKEN clock enable bit CLKOUTEN scanclock output enable bit CLKSELECT scanclock select bit CNT count bit D D*/A data/address line signal D/A digital-to-analog DAQD*/A dat
Glossary DIG GND digital ground signal DIN Deutsche Industrie Norme DMM digital multimeter DTEMP direct temperature sensor DTS direct temperature sensor E EGND# excitation ground number signal EX#+ positive excitation output number signal EX#– negative excitation output number signal F F Fahrenheit FIFO first-in-first-out FOUTEN* forced output enable bit FRT forced retransmit bit G GBWP gain bandwidth product GUARD guard signal H hex hexadecimal HSCR hardscan control register
Glossary HSRS* hardscan reset bit Hz hertz I II input current leakage in. inches INTR* interrupt signal I/O input/output K K kelvin L LOAD* load bit LSB least significant bit M m meters M megabytes of memory MCH#+ positive analog output channel number signal MCH#– negative analog output channel number signal MISO master-in slave-out signal MOD module number bit MOSI master-out slave-in signal MSB most significant bit SCXI-1121 User Manual Glossary-4 www.natinst.
Glossary MTEMP multiplexed temperature sensor MTS multiplexed temperature sensor N NRSE nonreferenced single-ended (input) O ONCE once bit OUTREF output reference signal P ppm parts per million R RAM random-access memory RD read bit RESET* reset signal rms root mean square RSE referenced single-ended (input) RSVD reserved bit/signal RTD resistance temperature detector RTEMP read temperature bit RTI referred to input RTO referred to output RTSI real time system integration
Glossary S SCAL (bit) shunt calibrate bit SCAL (signal) shunt calibration signal SCANCLK scan clock signal SCANCLKEN scan clock enable bit SCANCON scanning control signal SCANCONEN scan control enable bit SCXI Signal Conditioning eXtensions for Instrumentation (bus) SDK software developer’s kit sec seconds SERCLK serial clock signal SERDATIN serial data in signal SERDATOUT serial data out signal SL slot bit SLOT0SEL* slot 0 select signal SPI serial peripheral interface SPICLK
Glossary U UL Underwriters Laboratory V V volts V+ positive analog supply signal V– negative analog supply signal VDC volts direct current VIH volts input high VIL volts input low VOH volts output high VOL volts output low Vrms volts, root mean square W W watts © National Instruments Corporation Glossary-7 SCXI-1121 User Manual
Index Numbers +5 V signal front connector (table), 2-18, D-3 SCXIbus connector (table), 3-4 A AB0+ signal (table), 3-4, C-3 AB0- signal (table), 3-4, C-3 AB0EN bit, 4-4 AC-coupled signal connections external resistor required, 2-21 floating (figure), 2-21 referenced to chassis ground (figure), 2-20 acquisition enable, programming, 5-14 to 5-15 analog and timing circuitry, 3-8 to 3-16 analog input channels, 3-8 to 3-11 analog output circuitry, 3-15 to 3-16 calibration, 3-11 to 3-14 excitation output channel
Index C configuration analog, 2-6 to 2-13 excitation jumpers, 2-9 to 2-13 filter jumpers, 2-9 gain jumpers, 2-8 grounding, shielding, and reference mode selection, 2-6 to 2-7 input channel jumpers, 2-8 to 2-13 jumper W33, 2-6 to 2-7 digital signal connections jumper settings (figure), 2-5 to 2-6 jumper W32, 2-4 jumper W38, 2-4 jumper W44, 2-3 to 2-4 using jumpers W32 and W38, 2-4 to 2-5 excitation jumpers, 2-9 to 2-13 current and voltage jumpers, 2-9 to 2-10 excitation level, 2-10 to 2-11 internal half-br
Index using jumpers W32 and W38, 2-4 to 2-5 direct measurements, single-channel multiplexed output, 5-4 to 5-5 parallel output, 5-4 single-channel measurements, 5-4 to 5-5 direct multiplexed scanning, single-module, 5-11 documentation conventions used in manual, xi-xii related documentation, xii DTEMP signal (table), 2-18, D-3 DTS mode, terminal blocks, 2-31 to 2-32 Counter 1, scanning measurements, 5-9 to 5-10 current and voltage excitation jumpers, 2-9 to 2-10 custom cables, 1-5 D D*/A signal descripti
Index F H FIFO Register description, 4-9 register writes, 5-2 to 5-4 filter jumpers allocation (table), 2-9 description, 2-9 fixed jumpers, 2-2 floating signal connections AC-coupled (figure), 2-21 referenced to chassis ground (figure), 2-20 FOUTEN* bit, 4-5 front connector, 2-16 to 2-36 analog input channels, 2-20 to 2-22 connector-and-shell assembly, 2-22 to 2-24 excitation channels, 2-22 pin assignments (figure), 2-17, D-2 SCXI-1320, SCXI-1328, and SCXI-1321 terminal blocks, 2-24 to 2-36 signal descri
Index W33, 2-6 to 2-7 W38 configuration, 2-4 to 2-5 description, 2-4 settings (table), 2-5 W44 configuration, 2-3 to 2-4 settings (table), 2-6 W45 (table), 2-5 SCXI-1341 Lab-NB, Lab-PC, or Lab-PC+ cable assembly, E-6 SCXI-1342 PC-LPM-16 cable assembly, E-8 SCXI-1343 rear screw terminal adapter, E-14 SCXI-1344 Lab-PC+ cable assembly, E-6 SCXI-1350 multichassis adapter, E-13 SCXI-1351 one-slot cable extender, E-12 terminal blocks, 2-36 unpacking SCXI-1121, 1-6 internal half-bridge completion, 2-12 to 2-13 I
Index SCXIbus to SCXI-1121 rear signal connector to DAQ board pin equivalences (table), 2-41 MTEMP signal (table), 2-18, D-3 MTS mode, terminal blocks, 2-31 to 2-32 multiple-chassis scanning programming, 5-12 to 5-13 theory of operation, 3-20 multiplexed output, single-channel measurements, 5-4 to 5-5 multiplexed scanning multiple-module description, 3-19 programming, 5-12 overview, 3-17 to 3-18 single-module, 3-18 to 3-19 direct, 3-18 indirect, 3-18 to 3-19 programming, 5-11 to 5-12 Multiplexed-Output mod
Index R SCXI-1344 Lab-PC+ cable assembly, E-5 problem-solving and diagnostic resources, online, G-1 programming, 5-1 to 5-17 notation, 5-1 register writes, 5-2 to 5-4 initialization, 5-4 register selection and write procedure, 5-2 to 5-3 SCXI-1121 rear signal connector equivalences (table), 5-2 scanning measurements, 5-7 to 5-15 acquisition enable, triggering, and servicing, 5-14 to 5-15 Counter 1 and SCANDIV, 5-9 to 5-10 data acquisition board setup, 5-7 to 5-9 examples, 5-15 to 5-17 module programming,
Index multiple-module multiplexed scanning, 5-12 single-module multiplexed scanning, 5-11 to 5-12 single-module parallel scanning, 5-10 Slot 0 hardscan circuitry, 5-13 to 5-14 scanning modes, 3-17 to 3-20 analog output circuitry, 3-15 multiple-chassis scanning, 3-20 multiple-module multiplexed scanning, 3-19 multiplexed scanning, 3-17 to 3-18 single-module multiplexed scanning, 3-18 to 3-19 single-module parallel scanning, 3-17 SCXI-1121. See also configuration; installation; theory of operation.
Index trimmer potentiometer and corresponding channel (table), 2-25 to 2-27 using with RTDs and thermistors, 2-27 SCXI-1328 terminal block. See SCXI-1320 and SCXI-1328 terminal blocks.
Index rear signal connector, 2-37 to 2-46 analog output, 2-39 communication signals, 2-42 to 2-46 digital I/O, 2-40 to 2-41 pin assignments (figure), 2-37, B-1 signal descriptions (table), 2-38, B-2 timing requirements and communication protocol, 2-42 safety precautions, 2-15 to 2-16 SCXIbus connector equivalents for rear signal connector (table), 3-5 pin assignments (figure), 3-3, C-2 signal descriptions (table), 3-4 to 3-5, C-3 to C-4 terminal blocks, 2-33 to 2-36 single-channel measurements, programming
Index calibration equipment requirements, 3-11 to 3-14 excitation output channels, 3-11 block diagram of SCXI-1121, 3-1 digital control circuitry, 3-7 to 3-8 digital interface, 3-6 major components of SCXI-1121, 3-2 scanning modes, 3-17 to 3-20 multiple-chassis scanning, 3-20 multiple-module multiplexed scanning, 3-19 multiplexed scanning, 3-17 to 3-18 single-module multiplexed scanning, 3-18 to 3-19 single-module parallel scanning, 3-17 SCXIbus connector equivalents for rear signal connector (table), 3-5
Index W Web support from National Instruments, G-1 to G-2 online problem-solving and diagnostic resources, G-1 software-related resources, G-2 Worldwide technical support, G-2 Wxx jumpers. See jumpers. SCXI-1121 User Manual Index-12 www.natinst.
