TM NI cDAQ -918x/919x User Manual NI CompactDAQ 9181/9184/9188 Ethernet Chassis and NI CompactDAQ 9191 Wireless Chassis NI cDAQ-918x/919x User Manual Français Deutsch ni.
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Contents Chapter 1 Getting Started with the cDAQ Chassis Safety Guidelines.............................................................................................................. 1-3 Safety Guidelines for Hazardous Locations ............................................................. 1-3 Special Conditions for Hazardous Locations Use in Europe ........................... 1-4 Electromagnetic Compatibility Guidelines ......................................................................
Contents AI Sample Clock Signal ...........................................................................................2-2 Routing the Sample Clock to an Output Terminal ........................................... 2-2 AI Sample Clock Timebase Signal ........................................................................... 2-2 AI Convert Clock Signal Behavior For Analog Input Modules ............................... 2-2 Scanned Modules....................................................................
NI cDAQ-918x/919x User Manual Chapter 4 Digital Input/Output and PFI Digital Input/Output ......................................................................................................... 4-1 Serial DIO versus Parallel DIO Modules ................................................................. 4-1 Static DIO ................................................................................................................. 4-2 Digital Input............................................................
Contents Frequency Measurement...........................................................................................5-10 Low Frequency with One Counter.................................................................... 5-11 High Frequency with Two Counters................................................................. 5-11 Large Range of Frequencies with Two Counters ............................................. 5-12 Sample Clocked Buffered Frequency Measurement ....................................
NI cDAQ-918x/919x User Manual Counter n A, Counter n B, and Counter n Z Signals ................................................ 5-35 Routing Signals to A, B, and Z Counter Inputs................................................ 5-35 Routing Counter n Z Signal to an Output Terminal ......................................... 5-35 Counter n Up_Down Signal ..................................................................................... 5-36 Counter n HW Arm Signal ..........................................
1 Getting Started with the cDAQ Chassis This chapter provides a cDAQ chassis overview and lists information about mounting the chassis and installing C Series I/O modules. The one-slot NI CompactDAQ 9181 (cDAQ-9181), four-slot NI CompactDAQ 9184 (cDAQ-9184), and eight-slot NI CompactDAQ 9188 (cDAQ-9188) Ethernet chassis and the one-slot NI CompactDAQ 9191 (cDAQ-9191) wireless chassis are designed for use with C Series I/O modules.
Chapter 1 Getting Started with the cDAQ Chassis Figure 1-2 shows the NI cDAQ-9184 chassis. Figure 1-2. NI cDAQ-9184 Chassis 7 1 NI cDAQ-9184 NI CompactDAQ 6 4 5 1 2 3 4 2 3 Chassis Grounding Screw Installed C Series Module Module Slots Ethernet Connector, LINK/ACT and 10/100/1000 LEDs 5 6 7 9-30 VDC Power Connector Reset Button POWER, STATUS, and ACTIVE LEDs Figure 1-3 shows the NI cDAQ-9188 chassis. Figure 1-3.
NI cDAQ-918x/919x User Manual Safety Guidelines Operate the NI cDAQ-918x/919x chassis only as described in this user manual. Refer to the Read Me First: Safety and Electromagnetic Compatibility document for important safety and electromagnetic compatibility information. To obtain a copy of this document online, visit ni.com/manuals and search for the document title. Caution Do not operate the NI cDAQ-918x/919x in a manner not specified in this user manual. Product misuse can result in a hazard.
Chapter 1 Getting Started with the cDAQ Chassis Special Conditions for Hazardous Locations Use in Europe This equipment has been evaluated as Ex nA IIC T4 Gc equipment under DEMKO 12 ATEX 1202658X. Each such chassis is marked II 3G and is suitable for use in Zone 2 hazardous locations, in ambient temperatures of: • 0 °C ≤ Ta ≤ 55 °C for the NI cDAQ-9181/9191 • -20 °C ≤ Ta ≤ 55 °C for the NI cDAQ-9184/9188 You must make sure that transient disturbances do not exceed 140% of the rated voltage.
NI cDAQ-918x/919x User Manual Hardware Symbol Definitions The following symbols are marked on your cDAQ chassis. Caution When this symbol is marked on a product, refer to the Safety Guidelines section for information about precautions to take. At the end of the product life cycle, all products must be sent to a WEEE recycling center.
Chapter 1 Getting Started with the cDAQ Chassis Note The NI-DAQmx software is included on the disk shipped with your kit and is available for download at ni.com/support. The documentation for NI-DAQmx is available after installation from Start»All Programs»National Instruments» NI-DAQ. Other NI documentation is available from ni.com/manuals. Table 1-1 lists the earliest NI-DAQmx support version for each cDAQ Ethernet and wireless chassis. Table 1-1.
NI cDAQ-918x/919x User Manual Figure 1-4. Ring Lug Attached to Chassis Ground Terminal 5. Make sure that no signals are connected to the C Series I/O module. 6. Align the C Series I/O module with the cDAQ chassis slot. 7. Squeeze both C Series I/O module latches, insert the I/O module into the module slot, and press until both latches lock the module in place. 8. Wire the C Series I/O module as indicated in the C Series module documentation.
Chapter 1 Getting Started with the cDAQ Chassis Note Connect I/O cable shields to the chassis grounding screw, shown in Figure 1-4, unless otherwise specified in the C Series module documentation. Refer to the Chassis Grounding Screw section for more information about earth ground. 13. (NI cDAQ-9191) If you want to connect the NI cDAQ-9191 to a wireless network, complete the following steps: a. Double-click the Measurement & Automation icon, on the desktop to open MAX.
NI cDAQ-918x/919x User Manual Before connecting to an enterprise network, you may first need to upload a certificate by clicking Certificate Management. Contact your IT department if you are unsure of your network settings or configuration details. Note For EAP-TLS authentication, you must also upload a private key file with client certificate. Click Wireless Network to search for and select a network from the scanned list, or select Other Network and enter settings.
Chapter 1 Getting Started with the cDAQ Chassis Note Establishing a network connection may take several seconds. For more information about MAX configuration for the NI cDAQ-9191, refer to the Configuring the Wireless Settings for an NI cDAQ-919x topic in the Measurement & Automation Explorer Help for NI-DAQmx. Note 14. To add the chassis, double-click the Measurement & Automation icon on the desktop to open MAX. Expand Devices and Interfaces»Network Devices.
NI cDAQ-918x/919x User Manual Otherwise, enter the hostname of the chassis. The default hostname is cDAQ91xx-, where the xx represents the last two digits of your cDAQ chassis model number. The cDAQ chassis icon changes from white to blue, indicating that it is recognized and present on the network. Figure 1-5.
Chapter 1 Getting Started with the cDAQ Chassis Note If you connected the cDAQ chassis directly to your computer, the setup time may be longer. Wait 30-60 seconds after the STATUS LED turns off, then click Refresh List. • Contact your system administrator to confirm that the network is working and that a firewall is not interfering with discovery.
NI cDAQ-918x/919x User Manual 17. If the cDAQ chassis is not reserved automatically, select the chassis and click the Reserve Chassis button. Refer to the Reserving the Chassis in MAX section for more information. 18. Self-test your chassis in MAX by expanding Devices and Interfaces, right-clicking NI cDAQ-, and selecting Self-Test. Self-test performs a brief test to determine successful chassis installation.
Chapter 1 Getting Started with the cDAQ Chassis Reserving the Chassis in MAX When the cDAQ chassis is connected to a network, multiple users can access the chassis. To perform any DAQ functionality on the C Series modules, including reset chassis and self-test, you must reserve the cDAQ chassis in MAX. Only one user at a time can reserve the cDAQ chassis.
NI cDAQ-918x/919x User Manual Mounting the cDAQ Chassis You can use the cDAQ chassis on a desktop or mount it to a panel, wall, or DIN rail. For accessory ordering information, refer to the pricing section of your cDAQ chassis product page at ni.com. Caution Your installation must meet the following requirements: • Allows 25.4 mm (1 in.) of clearance above and below the cDAQ chassis for air circulation. • Allows at least 50.8 mm (2 in.
Chapter 1 Getting Started with the cDAQ Chassis NI 9901 Desktop Kit for NI cDAQ-9184/9188 Chassis The NI 9901 desktop mounting kit includes two metal feet you can install on the sides of the cDAQ chassis for desktop use. With this kit, you can tilt the cDAQ chassis for convenient access to the I/O module connectors. When you install the two metal feet, the two existing screws on the back side and I/O end of the chassis must be removed, as shown in Figure 1-7.
NI cDAQ-918x/919x User Manual NI cDAQ-9181/9191 You can panel mount the cDAQ chassis with or without a panel mount kit: Note The threaded holes on cDAQ chassis for panel or DIN rail mounting cannot be used more than five times. Unscrewing and reinstalling the screws into the chassis will produce a compromised connection between the panel and cDAQ chassis. Caution Remove the C Series I/O module(s) from the cDAQ chassis before you mount the chassis to the panel.
Chapter 1 Getting Started with the cDAQ Chassis Figure 1-9. NI 9903 Panel Mount Accessory Dimensions POWER STATUS ACTIVE 59.7 mm (2.35 in.) 14.0 mm (0.55 in.) 101.6 mm (4.00 in.) 38.1 mm (1.5 in.) 118.1 mm (4.65 in.) 1-18 | ni.
NI cDAQ-918x/919x User Manual • Panel Mounting without a Panel Mount Kit—Threaded holes are located in the cDAQ chassis for mounting it to a panel. Use two standard #6-32 UNC-2B machine screws with a maximum threaded engagement length of 4.83 mm (0.190 in.) to go through the panel and into the back of the chassis, as shown in Figure 1-10. National Instruments does not provide these screws with the chassis. Refer to the specifications document for your cDAQ chassis for mounting dimensions. Figure 1-10.
Chapter 1 Getting Started with the cDAQ Chassis NI cDAQ-9184/9188 You can panel mount the cDAQ chassis with or without a panel mount kit: • Panel Mounting with a Panel Mount Kit—Use the NI 9904 panel mount kit to mount the NI cDAQ-9184 chassis on a panel. Use the NI 9905 panel mount kit to mount the NI cDAQ-9188 chassis on a panel. Remove the C Series I/O module(s) from the cDAQ chassis before you mount the chassis to the panel. After the cDAQ chassis is mounted, you can reinsert the C Series module(s).
NI cDAQ-918x/919x User Manual Figure 1-11. NI cDAQ-9184/9188 Panel Mount Dimensions and Installation 330.2 mm (13.00 in.) 1 2 3 4 5 6 48.1 mm (1.90 in.) 7 8 88.1 mm (3.47 in.) 28.1 mm (1.11 in.) 234.95 mm (9.25 in.) NI cDAQ-8184 NI CompactDAQ 88.1 mm (3.47 in.) 29.49 mm (1.16 in.) NI NI 27.30 mm (1.08 in.
Chapter 1 • Getting Started with the cDAQ Chassis Panel Mounting without a Panel Mount Kit—You can mount the cDAQ chassis directly on a flat surface using the mounting holes. Align the chassis on the surface. Then, fasten the chassis to the surface using two screws as shown in Figure 1-12. The NI cDAQ-9184 uses two M4 or No. 8 flathead screws. The NI cDAQ-9188 uses two M4 or No. 8 panhead screws. National Instruments does not provide these screws with the chassis. Figure 1-12.
NI cDAQ-918x/919x User Manual NI cDAQ-9181/9191 The NI 9913 DIN rail mounting kit contains one clip for mounting the cDAQ chassis on a standard 35 mm DIN rail. Fasten the DIN rail clip to the cDAQ chassis using two FLH #6-32 × 5/16” screws (included in the kit) with a number 2 Phillips screwdriver, as shown in Figure 1-13. Note The threaded holes on NI cDAQ-9181/9191 chassis for panel or DIN rail mounting cannot be used more than five times.
Chapter 1 Getting Started with the cDAQ Chassis Figure 1-14. DIN Rail Clip Parts Locator Diagram 1 2 3 1 DIN Rail Clip 2 Caution DIN Rail Spring 3 DIN Rail Remove the I/O module before removing the chassis from the DIN rail. NI cDAQ-9184/9188 Use the NI 9912 DIN rail kit to mount the NI cDAQ-9184 chassis on a DIN rail. Use the NI 9915 DIN rail kit with the NI cDAQ-9188 chassis on a DIN rail. Each DIN rail mounting kit contains one clip for mounting the chassis on a standard 35 mm DIN rail.
NI cDAQ-918x/919x User Manual NI cDAQ Chassis Features The cDAQ chassis features a chassis grounding screw, LEDs, reset button, Ethernet connector, and power connector. The NI cDAQ-9188 chassis also features two PFI BNC connectors. The NI cDAQ-9191 chassis also features an antenna and antenna jack. Refer to Figure 1-1, 1-2, or 1-3 for locations of the cDAQ chassis features.
Chapter 1 Getting Started with the cDAQ Chassis LEDs The statuses for the 10/100/10001, LINK/ACT, POWER, STATUS, and ACTIVE LED indicators on the cDAQ chassis are listed in Table 1-3. The NI cDAQ-9191 also features four wireless signal strength LED indicators. Refer to Table 1-4 for the wireless signal strength LED patterns. Table 1-3.
NI cDAQ-918x/919x User Manual Table 1-4.
Chapter 1 Getting Started with the cDAQ Chassis Ethernet Cabling Table 1-5 shows the shielded Ethernet cable wiring connections for both straight through and crossover cables. Table 1-5.
NI cDAQ-918x/919x User Manual Reset Button The cDAQ chassis is equipped with a reset button. Pressing the reset button results in the following chassis responses: • When pressed for less than five seconds, the chassis reboots with the current configuration. • When pressed for five seconds or longer, the STATUS LED lights. When released, the chassis reboots into factory default mode, which returns the chassis user configuration to the factory-set defaults listed in Table 1-6. Table 1-6.
Chapter 1 Getting Started with the cDAQ Chassis Cables and Accessories Table 1-7 contains information about cables and accessories available for the cDAQ chassis. For a complete list of cDAQ chassis accessories and ordering information, refer to the pricing section of your cDAQ chassis product page at ni.com. Table 1-7.
NI cDAQ-918x/919x User Manual Using the cDAQ Chassis The cDAQ system consists of three parts: C Series I/O module(s), the cDAQ module interface, and the STC3, as shown in Figure 1-16. These components digitize signals, perform D/A conversions to generate analog output signals, measure and control digital I/O signals, and provide signal conditioning. Figure 1-16.
Chapter 1 Getting Started with the cDAQ Chassis Parallel versus Serial DIO Modules Digital I/O module capabilities are determined by the type of digital signals that the module is capable of measuring or generating. • Serial digital I/O modules are designed for signals that change slowly and are accessed by software-timed reads and writes. • Parallel digital I/O modules are for signals that change rapidly and are updated by either software-timed or hardware-timed reads and writes.
NI cDAQ-918x/919x User Manual • Independent Data Streams—The NI cDAQ-9181/9191 supports six independent high-speed data streams, which allow for up to six simultaneous hardware-timed tasks, such as analog input, analog output, buffered counter/timers, and hardware-timed digital input/output.
2 Analog Input To perform analog input measurements, insert a supported analog input C Series I/O module into any slot on the cDAQ chassis. The measurement specifications, such as number of channels, channel configuration, sample rate, and gain, are determined by the type of C Series I/O module used. For more information and wiring diagrams, refer to the documentation included with your C Series I/O modules.
Chapter 2 Analog Input • AI Reference Trigger Signal* • AI Pause Trigger Signal* Signals with an * support digital filtering. Refer to the PFI Filters section of Chapter 4, Digital Input/Output and PFI, for more information. Refer to the AI Convert Clock Signal Behavior For Analog Input Modules section for AI Convert Clock signals and the cDAQ chassis. AI Sample Clock Signal A sample consists of one reading from each channel in the AI task.
NI cDAQ-918x/919x User Manual Scanned Modules Scanned C Series analog input modules contain a single A/D converter and a multiplexer to select between multiple input channels. When the cDAQ Module Interface receives a Sample Clock pulse, it begins generating a Convert Clock for each scanned module in the current task. Each Convert Clock signals the acquisition of a single channel from that module.
Chapter 2 Analog Input relative to non-sigma-delta modules in the system. This input delay is specified in the C Series I/O module documentation. Slow Sample Rate Modules (NI cDAQ-9184/9188) Some C Series analog input modules are specifically designed for measuring signals that vary slowly, such as temperature. Because of their slow rate, it is not appropriate for these modules to constrain the AI Sample Clock to operate at or slower than their maximum rate.
NI cDAQ-918x/919x User Manual An acquisition that uses a start trigger (but not a reference trigger) is sometimes referred to as a posttriggered acquisition. That is, samples are measured only after the trigger. When you are using an internal sample clock, you can specify a default delay from the start trigger to the first sample. Using a Digital Source To use the Start Trigger signal with a digital source, specify a source and a rising or falling edge.
Chapter 2 Analog Input When the reference trigger occurs, the cDAQ chassis continues to write samples to the buffer until the buffer contains the number of posttrigger samples desired. Figure 2-3 shows the final buffer. Figure 2-3. Reference Trigger Final Buffer Reference Trigger Pretrigger Samples Posttrigger Samples Complete Buffer Using a Digital Source To use Reference Trigger with a digital source, specify a source and a rising or falling edge.
NI cDAQ-918x/919x User Manual Using an Analog Source Some C Series I/O modules can generate a trigger based on an analog signal. In NI-DAQmx, this is called the Analog Comparison Event. When you use an analog trigger source, the internal sample clock pauses when the Analog Comparison Event signal is low and resumes when the signal goes high (or vice versa). Note Depending on the C Series I/O module capabilities, you may need two modules to utilize analog triggering.
3 Analog Output To generate analog output, insert an analog output C Series I/O module in any slot on the cDAQ chassis. The generation specifications, such as the number of channels, channel configuration, update rate, and output range, are determined by the type of C Series I/O module used. For more information, refer to the documentation included with your C Series I/O module(s).
Chapter 3 Analog Output Hardware-Timed Generations With a hardware-timed generation, a digital hardware signal controls the rate of the generation. This signal can be generated internally on the chassis or provided externally.
NI cDAQ-918x/919x User Manual Analog Output Triggering Signals Analog output supports two different triggering actions: AO Start Trigger and AO Pause Trigger. An analog or digital trigger can initiate these actions. Up to two C Series parallel digital input modules can be used in any chassis slot to supply a digital trigger. An analog trigger can be supplied by some C Series analog modules.
Chapter 3 Analog Output Routing AO Sample Clock to an Output Terminal You can route AO Sample Clock to any output PFI terminal. AO Sample Clock is active high by default. AO Sample Clock Timebase Signal The AO Sample Clock Timebase (ao/SampleClockTimebase) signal is divided down to provide a source for AO Sample Clock. AO Sample Clock Timebase can be generated from external or internal sources, and is not available as an output from the chassis.
NI cDAQ-918x/919x User Manual AO Pause Trigger Signal Use the AO Pause Trigger signal (ao/PauseTrigger) to mask off samples in a DAQ sequence. When AO Pause Trigger is active, no samples occur, but AO Pause Trigger does not stop a sample that is in progress. The pause does not take effect until the beginning of the next sample. When you generate analog output signals, the generation pauses as soon as the pause trigger is asserted.
Chapter 3 Analog Output When you use an analog trigger source, the samples are paused when the Analog Comparison Event signal is at a high or low level, depending on the trigger properties. The analog trigger circuit must be configured by a simultaneously running analog input task. Note Depending on the C Series I/O module capabilities, you may need two modules to utilize analog triggering.
Digital Input/Output and PFI 4 This chapter describes the digital input/output (DIO) and Programmable Function Interface (PFI) functionality available on the cDAQ chassis. Refer to the Digital Input/Output and PFI sections. Digital Input/Output To use digital I/O, insert a digital I/O C Series module into any slot on the cDAQ chassis. The I/O specifications, such as number of lines, logic levels, update rate, and line direction, are determined by the type of C Series I/O module used.
Chapter 4 Digital Input/Output and PFI Static DIO Each of the DIO lines can be used as a static DI or DO line. You can use static DIO lines to monitor or control digital signals on some C Series I/O modules. Each DIO line can be individually configured as a digital input (DI) or digital output (DO), if the C Series I/O module being used allows such configuration. All samples of static DI lines and updates of static DO lines are software-timed.
NI cDAQ-918x/919x User Manual DI Sample Clock Signal Use the DI Sample Clock (di/SampleClock) signal to sample digital I/O on any slot using parallel digital modules, and store the result in the DI waveform acquisition FIFO. If the cDAQ chassis receives a DI Sample Clock signal when the FIFO is full, it reports an overflow error to the host software. A sample consists of one reading from each channel in the DI task. DI Sample Clock signals the start of a sample of all digital input channels in the task.
Chapter 4 Digital Input/Output and PFI Using an External Source You can route the following signals as DI Sample Clock: • Any PFI terminal • Analog Comparison Event (an analog trigger) You can sample data on the rising or falling edge of DI Sample Clock. Routing DI Sample Clock to an Output Terminal You can route DI Sample Clock to any output PFI terminal. The PFI circuitry inverts the polarity of DI Sample Clock before driving the PFI terminal.
NI cDAQ-918x/919x User Manual Routing DI Start Trigger to an Output Terminal You can route DI Start Trigger to any output PFI terminal. The output is an active high pulse. DI Reference Trigger Signal Use a reference trigger (di/ReferenceTrigger) signal to stop a measurement acquisition. To use a reference trigger, specify a buffer of finite size and a number of pretrigger samples (samples that occur before the reference trigger).
Chapter 4 Digital Input/Output and PFI Using an Analog Source Some C Series I/O modules can generate a trigger based on an analog signal. In NI-DAQmx, this is called the Analog Comparison Event. When you use an analog trigger source, the acquisition stops on the first rising or falling edge of the Analog Comparison Event signal, depending on the trigger properties. Note Depending on the C Series I/O module capabilities, you may need two modules to utilize analog triggering.
NI cDAQ-918x/919x User Manual In NI-DAQmx, the filter is programmed by setting the minimum pulse width, Tp1, that will pass the filter, and is selectable in 25 ns increments. The appropriate Filter Clock is selected by the driver. Pulses of length less than 1/2 Tp will be rejected, and the filtering behavior of lengths between 1/2 Tp and 1 Tp are not defined because they depend on the phase of the Filter Clock relative to the input signal.
Chapter 4 Digital Input/Output and PFI Change detection acquisitions can be buffered or nonbuffered: • Nonbuffered Change Detection Acquisition—In a nonbuffered acquisition, data is transferred from the cDAQ chassis directly to a PC buffer. • Buffered Change Detection Acquisition—A buffer is a temporary storage in computer memory for acquired samples. In a buffered acquisition, data is stored in the cDAQ chassis onboard FIFO then transferred to a PC buffer.
NI cDAQ-918x/919x User Manual Hardware-timed generations have several advantages over software-timed acquisitions: • The time between samples can be much shorter. • The timing between samples is deterministic. • Hardware-timed acquisitions can use hardware triggering. Hardware-timed DO operations on the cDAQ chassis must be buffered. Buffered Digital Output A buffer is a temporary storage in computer memory for generated samples.
Chapter 4 Digital Input/Output and PFI Digital Output Triggering Signals Digital output supports two different triggering actions: DO Start Trigger and DO Pause Trigger. A digital or analog trigger can initiate these actions. Any PFI terminal can supply a digital trigger, and some C Series analog modules can supply an analog trigger. For more information, refer to the documentation included with your C Series I/O module(s).
NI cDAQ-918x/919x User Manual DO Sample Clock Timebase Signal The DO Sample Clock Timebase (do/SampleClockTimebase) signal is divided down to provide a source for DO Sample Clock. DO Sample Clock Timebase can be generated from external or internal sources, and is not available as an output from the chassis. DO Start Trigger Signal Use the DO Start Trigger (do/StartTrigger) signal to initiate a waveform generation. If you do not use triggers, you can begin a generation with a software command.
Chapter 4 Digital Input/Output and PFI When you generate digital output signals, the generation pauses as soon as the pause trigger is asserted. If the source of the sample clock is the onboard clock, the generation resumes as soon as the pause trigger is deasserted, as shown in Figure 4-5. Figure 4-5.
NI cDAQ-918x/919x User Manual Getting Started with DO Applications in Software You can use the cDAQ chassis in the following digital output applications: • Single-point (on-demand) generation • Finite generation • Continuous generation For more information about programming digital output applications and triggers in software, refer the LabVIEW Help or to the NI-DAQmx Help.
Chapter 4 Digital Input/Output and PFI Assume that an input terminal has been low for a long time. The input terminal then changes from low to high, but glitches several times. When the Filter Clock has sampled the signal high on N consecutive edges, the low-to-high transition is propagated to the rest of the circuit. The value of N depends on the filter setting, as shown in Table 4-1. Table 4-1. Selectable PFI Filter Settings Filter Setting Filter Clock Jitter Min Pulse Width* to Pass 112.
5 Counters The cDAQ chassis has four general-purpose 32-bit counter/timers and one frequency generator. The general-purpose counter/timers can be used for many measurement and pulse generation applications. Figure 5-1 shows the cDAQ chassis Counter 0 and the frequency generator. All four counters on the cDAQ chassis are identical. Figure 5-1.
Chapter 5 Counters Counter Timing Engine Unlike analog input, analog output, digital input, and digital output, the cDAQ chassis counters do not have the ability to divide down a timebase to produce an internal counter sample clock. For sample clocked operations, an external signal must be provided to supply a clock source.
NI cDAQ-918x/919x User Manual Table 5-1.
Chapter 5 Counters You also can use a pause trigger to pause (or gate) the counter. When the pause trigger is active, the counter ignores edges on its Source input. When the pause trigger is inactive, the counter counts edges normally. You can route the pause trigger to the Gate input of the counter. You can configure the counter to pause counting when the pause trigger is high or when it is low. Figure 5-3 shows an example of on-demand edge counting with a pause trigger. Figure 5-3.
NI cDAQ-918x/919x User Manual Controlling the Direction of Counting In edge counting applications, the counter can count up or down. You can configure the counter to do the following: • Always count up • Always count down • Count up when the Counter 0 B input is high; count down when it is low For information about connecting counter signals, refer to the Default Counter/Timer Routing section.
Chapter 5 Counters Figure 5-5 shows an example of a single pulse-width measurement. Figure 5-5. Single Pulse-Width Measurement GATE SOURCE Counter Value 0 1 2 Latched Value 2 Implicit Buffered Pulse-Width Measurement An implicit buffered pulse-width measurement is similar to single pulse-width measurement, but buffered pulse-width measurement takes measurements over multiple pulses. The counter counts the number of edges on the Source input while the Gate input remains active.
NI cDAQ-918x/919x User Manual Figure 5-7 shows an example of a sample clocked buffered pulse-width measurement. Figure 5-7. Sample Clocked Buffered Pulse-Width Measurement Pulse Source 2 2 4 2 2 3 Sample Clock Note 4 3 4 Buffer If a pulse does not occur between sample clocks, an overrun error occurs. For information about connecting counter signals, refer to the Default Counter/Timer Routing section.
Chapter 5 Counters Single Pulse Measurement Single (on-demand) pulse measurement is equivalent to two single pulse-width measurements on the high (H) and low (L) ticks of a pulse, as shown in Figure 5-8. Figure 5-8. Single (On-Demand) Pulse Measurement Counter Armed Gate Source Latched Value H L 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 9 10 7 10 Implicit Buffered Pulse Measurement In an implicit buffered pulse measurement, on each edge of the Gate signal, the counter stores the count in the FIFO.
NI cDAQ-918x/919x User Manual Figure 5-10 shows an example of a sample clocked buffered pulse measurement. Figure 5-10. Sample Clocked Buffered Pulse Measurement Counter Armed S2 S1 Gate Source Sample Clock Buffer 2 Note 2 HL 2 2 3 3 H L 2 2 3 3 If a pulse does not occur between sample clocks, an overrun error occurs. For information about connecting counter signals, refer to the Default Counter/Timer Routing section.
Chapter 5 Counters Implicit Buffered Semi-Period Measurement In implicit buffered semi-period measurements, on each edge of the Gate signal, the counter stores the count in the FIFO. The STC3 transfers the sampled values to host memory using a high-speed data stream. The counter begins counting when it is armed. The arm usually occurs between edges on the Gate input. You can select whether to read the first active low or active high semi period using the CI.SemiPeriod.StartingEdge property in NI-DAQmx.
NI cDAQ-918x/919x User Manual • Large Range of Frequencies with Two Counters • Sample Clocked Buffered Frequency Measurement Low Frequency with One Counter For low frequency measurements with one counter, you measure one period of your signal using a known timebase. You can route the signal to measure (fx) to the Gate of a counter. You can route a known timebase (fk) to the Source of the counter.
Chapter 5 Counters Figure 5-13 illustrates this method. Another option is to measure the width of a known period instead of a known pulse. Figure 5-13. High Frequency with Two Counters Width of Pulse (T ) Pulse Pulse Gate 1 fx Source Pulse-Width Measurement 2 … N fx Width of T = Pulse Frequency of fx = N fx N T Large Range of Frequencies with Two Counters By using two counters, you can accurately measure a signal that might be high or low frequency.
NI cDAQ-918x/919x User Manual You can route the signal to measure to the Source input of Counter 0, as shown in Figure 5-14. Assume this signal to measure has frequency fx. NI-DAQmx automatically configures Counter 0 to generate a single pulse that is the width of N periods of the source input signal. Figure 5-14.
Chapter 5 Counters Figure 5-15. Sample Clocked Buffered Frequency Measurement (Averaging) Counter Armed S1 S2 S3 Gate (fx) 1 2 1 6 10 6 Source (fk) Sample Clock T1 T2 1 6 Buffer T1 T2 1 7 2 10 T1T2 1 7 2 10 1 6 When CI.Freq.EnableAveraging is set to false, the frequency measurement returns the frequency of the pulse just before the sample clock. This single measurement is a single frequency measurement and is not an average between clocks as shown in Figure 5-16. Figure 5-16.
NI cDAQ-918x/919x User Manual Divide down (N) is the integer to divide down measured frequency, only used in large range two counters fs is the sample clock rate, only used in sample clocked frequency measurements Here is how these variables apply to each method, summarized in Table 5-2. • One counter—With one counter measurements, a known timebase is used for the source frequency (fk). The measurement time is the period of the frequency to be measured, or 1/fx.
Chapter 5 Counters Which Method Is Best? This depends on the frequency to be measured, the rate at which you want to monitor the frequency and the accuracy you desire. Take for example, measuring a 50 kHz signal. Assuming that the measurement times for the sample clocked (with averaging) and two counter frequency measurements are configured the same, Table 5-3 summarizes the results. Table 5-3.
NI cDAQ-918x/919x User Manual From this, you can see that while the measurement time for one counter is shorter, the accuracy is best in the sample clocked and two counter large range measurements. For another example, Table 5-4 shows the results for 5 MHz. Table 5-4. 5 MHz Frequency Measurement Methods Two Counter Sample Clocked One Counter High Frequency Large Range fx 5M 5M 5M 5M fk 80 M 80 M 1,000 80 M Measurement time (mS) 1 .0002 1 1 N — — — 5,000 Max.
Chapter 5 • Counters Measuring a large range of frequencies with two counters measures high and low frequency signals accurately. However, it requires two counters, and it has a variable sample time and variable error % dependent on the input signal. Table 5-5 summarizes some of the differences in methods of measuring frequency. Table 5-5.
NI cDAQ-918x/919x User Manual Position Measurement You can use the counters to perform position measurements with quadrature encoders or two-pulse encoders. You can measure angular position with X1, X2, and X4 angular encoders. Linear position can be measured with two-pulse encoders. You can choose to do either a single point (on-demand) position measurement or a buffered (sample clock) position measurement. You must arm a counter to begin position measurements.
Chapter 5 • Counters X4 Encoding—Similarly, the counter increments or decrements on each edge of channels A and B for X4 encoding. Whether the counter increments or decrements depends on which channel leads the other. Each cycle results in four increments or decrements, as shown in Figure 5-19. Figure 5-19.
NI cDAQ-918x/919x User Manual Measurements Using Two Pulse Encoders The counter supports two pulse encoders that have two channels—channels A and B. The counter increments on each rising edge of channel A. The counter decrements on each rising edge of channel B, as shown in Figure 5-21. Figure 5-21. Measurements Using Two Pulse Encoders Ch A Ch B Counter Value 2 3 4 5 4 3 4 For information about connecting counter signals, refer to the Default Counter/Timer Routing section.
Chapter 5 Counters After the counter has been armed and an active edge occurs on the Aux input, the counter counts the number of rising (or falling) edges on the Source. The counter ignores additional edges on the Aux input. The counter stops counting upon receiving an active edge on the Gate input. The counter stores the count in the FIFO. You can configure the rising or falling edge of the Aux input to be the active edge.
NI cDAQ-918x/919x User Manual the count in the FIFO. On the next active edge of the Gate signal, the counter begins another measurement. The STC3 transfers the sampled values to host memory using a high-speed data stream. Figure 5-24 shows an example of an implicit buffered two-signal edge-separation measurement. Figure 5-24.
Chapter 5 Counters Counter Output Applications The following sections list the various counter output applications available on the cDAQ chassis: • Simple Pulse Generation • Pulse Train Generation • Frequency Generation • Frequency Division • Pulse Generation for ETS Simple Pulse Generation Refer to the following sections for more information about the cDAQ chassis simple pulse generation options: • Single Pulse Generation • Single Pulse Generation with Start Trigger Single Pulse Generation
NI cDAQ-918x/919x User Manual Single Pulse Generation with Start Trigger The counter can output a single pulse in response to one pulse on a hardware Start Trigger signal. The pulse appears on the Counter n Internal Output signal of the counter. You can specify a delay from the Start Trigger to the beginning of the pulse. You also can specify the pulse width. The delay is measured in terms of a number of active edges of the Source input. You can specify a pulse width.
Chapter 5 Counters Figure 5-28. Finite Pulse Train Generation: Four Ticks Initial Delay, Four Pulses Counter Armed Source Enablex Ctrx Retriggerable Pulse or Pulse Train Generation The counter can output a single pulse or multiple pulses in response to each pulse on a hardware Start Trigger signal. The generated pulses appear on the Counter n Internal Output signal of the counter. You can route the Start Trigger signal to the Gate input of the counter.
NI cDAQ-918x/919x User Manual Figure 5-30 shows the same pulse train with CO.EnableInitalDelayOnRetrigger set to the default False. Figure 5-30. Retriggerable Single Pulse Generation False Counter Load Values 4 3 2 1 0 2 1 0 4 3 2 1 0 2 1 0 GATE (Start Trigger) SOURCE OUT 5 3 2 3 Note The minimum time between the trigger and the first active edge is two ticks of the source. For information about connecting counter signals, refer to the Default Counter/Timer Routing section.
Chapter 5 Counters Continuous pulse train generation is sometimes called frequency division. If the high and low pulse widths of the output signal are M and N periods, then the frequency of the Counter n Internal Output signal is equal to the frequency of the Source input divided by M + N. For information about connecting counter signals, refer to the Default Counter/Timer Routing section.
NI cDAQ-918x/919x User Manual Figure 5-32. Finite Implicit Buffered Pulse Train Generation SOURCE OUT 2 2 3 4 2 2 Counter Armed Continuous Buffered Implicit Pulse Train Generation This function generates a continuous train of pulses with variable idle and active times. Instead of generating a set number of data samples and stopping, a continuous generation continues until you stop the operation. Each point you write generates a single pulse.
Chapter 5 Counters Figure 5-33. Finite Buffered Sample Clocked Pulse Train Generation Counter Armed Sample Clock Counter Load Values 2 1 0 1 0 1 0 1 0 2 1 0 2 1 0 2 1 0 2 1 0 1 0 1 0 2 1 0 2 1 0 Source Out 3 2 2 2 3 3 3 3 2 2 3 3 There are several different methods of continuous generation that control what data is written. These methods are regeneration, FIFO regeneration, and non-regeneration modes. Regeneration is the repetition of the data that is already in the buffer.
NI cDAQ-918x/919x User Manual Figure 5-34 shows a block diagram of the frequency generator. Figure 5-34. Frequency Generator Block Diagram 20 MHz Timebase ÷2 Frequency Output Timebase Frequency Generator FREQ OUT 100 kHz Timebase Divisor (1–16) The frequency generator generates the Frequency Output signal. The Frequency Output signal is the Frequency Output Timebase divided by a number you select from 1 to 16.
Chapter 5 Counters Pulse Generation for ETS In the equivalent time sampling (ETS) application, the counter produces a pulse on the output a specified delay after an active edge on Gate. After each active edge on Gate, the counter cumulatively increments the delay between the Gate and the pulse on the output by a specified amount. Thus, the delay between the Gate and the pulse produced successively increases. The increase in the delay value can be between 0 and 255.
NI cDAQ-918x/919x User Manual • Counter n Up_Down Signal • Counter n HW Arm Signal • Counter n Sample Clock Signal • Counter n Internal Output Signal • Counter n TC Signal • Frequency Output Signal In this section, n refers to the cDAQ chassis Counter 0, 1, 2, or 3.
Chapter 5 Counters Routing a Signal to Counter n Source Each counter has independent input selectors for the Counter n Source signal. Any of the following signals can be routed to the Counter n Source input: • 80 MHz Timebase • 20 MHz Timebase • 100 kHz Timebase • Any PFI terminal • Analog Comparison Event • Change Detection Event In addition, TC or Gate from a counter can be routed to a different counter source. Some of these options may not be available in some driver software.
NI cDAQ-918x/919x User Manual Some of these options may not be available in some driver software. Refer to the Device Routing in MAX topic in the NI-DAQmx Help or the LabVIEW Help for more information about available routing options. Routing Counter n Gate to an Output Terminal You can route Counter n Gate out to any PFI terminal. Counter n Aux Signal The Counter n Aux signal indicates the first edge in a two-signal edge-separation measurement.
Chapter 5 Counters Counter n Up_Down Signal Counter n Up_Down is another name for the Counter n B signal. Counter n HW Arm Signal The Counter n HW Arm signal enables a counter to begin an input or output function. To begin any counter input or output function, you must first enable, or arm, the counter. In some applications, such as a buffered edge count, the counter begins counting when it is armed.
NI cDAQ-918x/919x User Manual Using an Internal Source To use Counter n Sample Clock with an internal source, specify the signal source and the polarity of the signal. The source can be any of the following signals: • DI Sample Clock • DO Sample Clock • AI Sample Clock (ai/SampleClock, te0/SampleClock, te1/SampleClock) • AI Convert Clock • AO Sample Clock • DI Change Detection output Several other internal signals can be routed to Counter n Sample Clock through internal routes.
Chapter 5 Counters Routing Frequency Output to a Terminal You can route Frequency Output to any PFI terminal. Default Counter/Timer Routing Counter/timer signals are available to parallel digital I/O C Series modules. To determine the signal routing options for modules installed in your system, refer to the Device Routes tab in MAX. You can use these defaults or select other sources and destinations for the counter/timer signals in NI-DAQmx.
NI cDAQ-918x/919x User Manual Other Counter Features The following sections list the other counter features available on the cDAQ chassis. Cascading Counters You can internally route the Counter n Internal Output and Counter n TC signals of each counter to the Gate inputs of the other counter. By cascading two counters together, you can effectively create a 64-bit counter. By cascading counters, you also can enable other applications.
Chapter 5 Counters 80 MHz Source Mode In 80 MHz source mode, the chassis synchronizes signals on the rising edge of the source, and counts on the third rising edge of the source. Edges are pipelined so no counts are lost, as shown in Figure 5-38. Figure 5-38.
Digital Routing and Clock Generation 6 This chapter describes the digital routing and clock routing circuitry on the cDAQ chassis. Refer to the Digital Routing and Clock Routing sections. Digital Routing The digital routing circuitry has the following functions: • Manages the flow of data between the bus interface and the acquisition/generation sub-systems (analog input, analog output, digital I/O, and the counters).
Chapter 6 Digital Routing and Clock Generation 80 MHz Timebase You can use the 80 MHz Timebase as the Source input to the 32-bit general-purpose counter/timers. The 80 MHz Timebase can be generated from the onboard oscillator. 20 MHz Timebase The 20 MHz Timebase normally generates many of the AI and AO timing signals. It can function as the Source input to the 32-bit general-purpose counter/timers. The 20 MHz Timebase is generated by dividing down the 80 MHz Timebase, as shown in Figure 6-1.
NI cDAQ-9191 Regulatory Information A United States This product generates and radiates radio frequency energy. To comply with the radio frequency radiation exposure guidelines in an uncontrolled environment, this equipment must be installed and operated while maintaining a minimum body-to-antenna distance of 20 cm. This product complies with Part 15 of the FCC Rules.
Appendix A NI cDAQ-9191 Regulatory Information This device has been certified for use in Canada. Status of the listing in the Industry Canada’s REL (Radio Equipment List) can be found at the following web address: http://www.ic.gc.ca/app/sitt/reltel/srch/nwRdSrch.do?lang=eng Additional Canadian information on RF exposure also can be found at the following web address: http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf08792.
NI cDAQ-918x/919x User Manual EU Regulatory Statements Česky [Czech] National Instruments tímto prohlašuje, že tento NI cDAQ-9191 je ve shodě se základními požiadavkami a dalšími příslušnými ustanoveními směrnice 1999/5/ES. Dansk [Danish] Undertegnede National Instruments erklćrer herved, at fřlgende udstyr NI cDAQ-9191 overholder de vćsentlige krav og řvrige relevante krav i direktiv 1999/5/EF.
Appendix A NI cDAQ-9191 Regulatory Information Magyar [Hungarian] Alulírott, National Instruments nyilatkozom, hogy a NI cDAQ-9191 megfelel a vonatkozó alapvetõ követelményeknek és az 1999/5/EC irányelv egyéb elõírásainak. Polski [Polish] Niniejszym National Instruments. oświadcza, że NI cDAQ-9191 jest zgodny z zasadniczymi wymogami oraz pozostałymi stosownymi postanowieniami Dyrektywy 1999/5/EC.
NI cDAQ-918x/919x User Manual Taiwan R.O.C. Brasil – Aviso da Anatel Modelo: SX-10WG 1047-14-9143 *0107898581340997* (01)07898581340997 Este equipamento opera em caráter secundário, isto é, não tem direito a proteção contra interferência prejudicial, mesmo de estações do mesmo tipo, e não pode causar interferência a sistemas operando em caráter primário.
Where to Go from Here B This section lists where you can find example programs for the cDAQ chassis and C Series modules and relevant documentation. Example Programs NI-DAQmx software includes example programs to help you get started programming with the cDAQ chassis and C Series modules. Modify example code and save it in an application, or use examples to develop a new application, or add example code to an existing application. To locate NI software examples, go to ni.
Appendix B Where to Go from Here NI-DAQmx The NI-DAQ Readme lists which devices, ADEs, and NI application software are supported by this version of NI-DAQ. Select Start»All Programs»National Instruments»NI-DAQmx» NI-DAQ Readme. The NI-DAQmx Help contains API overviews, general information about measurement concepts, key NI-DAQmx concepts, and common applications that are applicable to all programming environments. Select Start»All Programs»National Instruments» NI-DAQmx»NI-DAQmx Help.
NI cDAQ-918x/919x User Manual The NI-DAQmx Library book of the LabWindows/CVI Help contains API overviews and function reference for NI-DAQmx. Select Library Reference»NI-DAQmx Library in the LabWindows/CVI Help. Measurement Studio If you program your NI-DAQmx-supported device in Measurement Studio using Visual C# or Visual Basic .NET, you can interactively create channels and tasks by launching the DAQ Assistant from MAX or from within Visual Studio.
Appendix B Where to Go from Here .NET Languages without NI Application Software With the Microsoft .NET Framework, you can use NI-DAQmx to create applications using Visual C# and Visual Basic .NET without Measurement Studio. Refer to the NI-DAQmx Readme for specific versions supported. Training Courses If you need more help getting started developing an application with NI products, NI offers training courses. To enroll in a course or obtain a detailed course outline, refer to ni.com/ training.
Technical Support and Professional Services C Log in to your National Instruments ni.com User Profile to get personalized access to your services. Visit the following sections of ni.com for technical support and professional services: • Support—Technical support at ni.com/support includes the following resources: – Self-Help Technical Resources—For answers and solutions, visit ni.
Appendix C Technical Support and Professional Services You also can visit the Worldwide Offices section of ni.com/niglobal to access the branch office websites, which provide up-to-date contact information, support phone numbers, email addresses, and current events. C-2 | ni.
Index Symbols <20 MHz source mode, 5-40 Numerics 10/100 LED, 1-26 10/100/1000 LED, 1-26 80 MHz source mode, 5-40 A accessories, 1-30 acquisitions, digital waveform, 4-2 ACTIVE LED, 1-26 analog input getting started with applications in software, 2-7 timing signals, 2-1 triggering, 2-1 analog input signals AI Convert Clock behavior, 2-2 AI Pause Trigger, 2-6 AI Reference Trigger, 2-5 AI Sample Clock, 2-2 AI Sample Clock Timebase, 2-2 AI Start Trigger, 2-4 analog output data generation methods, 3-1 getting
Index unpacking, 1-5 using, 1-31 cDAQ module interface, 1-32 channel Z behavior, 5-20 chassis grounding screw, 1-25 choosing frequency measurement, 5-14 configuration, 1-5 connector PFI BNC, 1-29 power, 1-29 continuous pulse train generation, 5-27 controlling counting direction, 5-3 counter signals Counter n A, 5-35 Counter n Aux, 5-35 Counter n B, 5-35 Counter n Gate, 5-34 Counter n HW Arm, 5-36 Counter n Internal Output, 5-37 Counter n Source, 5-33 Counter n TC, 5-37 Counter n Up_Down, 5-36 FREQ OUT, 5-3
NI cDAQ-918x/919x User Manual E edge counting, 5-3 buffered, 5-4 on-demand, 5-3 sample clock, 5-4 single point, 5-3 edge-separation measurement buffered two-signal, 5-22 single two-signal, 5-22 electromagnetic compatibility guidelines, 1-4 encoders, quadrature, 5-19 encoding X1, 5-19 X2, 5-19 X4, 5-20 equivalent time sampling, 5-32 Ethernet cabling, 1-28 example programs, B-1 examples (NI resources), C-1 external source less than 40 MHz, 5-40 F features, counter, 5-39 filters digital input (parallel DIO m
Index M P MAX chassis reservation, 1-14 Measurement Studio documentation, B-3 measurements buffered two-signal edge-separation, 5-22 choosing frequency, 5-14 frequency, 5-10 implicit buffered pulse-width, 5-6 implicit buffered semi-period, 5-10 period, 5-18 position, 5-19 pulse-width, 5-5 semi-period, 5-9 single pulse-width, 5-5 single semi-period, 5-9 single two-signal edge-separation, 5-22 two-signal edge-separation, 5-21 using quadrature encoders, 5-19 using two pulse encoders, 5-21 measuring high fre
NI cDAQ-918x/919x User Manual simple pulse generation, 5-24 single point edge counting, 5-3 pulse generation, 5-24 retriggerable, 5-26 with start trigger, 5-25 pulse-width measurement, 5-5 semi-period measurement, 5-9 two-signal edge-separation measurement, 5-22 software (NI resources), C-1 software-timed generations analog output, 3-1 digital output, 4-8 start trigger, 5-38 STATUS LED, 1-26 STC3, 1-32 support, technical, C-1 synchronization modes, 5-39 100 MHz source, 5-40 external source less than 40 MHz
