D1000 SERIES USERS MANUAL REVISED: 10/1/97 DGH CORPORATION P. O. BOX 5638 MANCHESTER, NH 03108 TELEPHONE: 603-622-0452 FAX: 603-622-0487 URL: http://www.dghcorp.com The information in this publication has been carefully checked and is believed to be accurate; however, no responsibility is assumed for possible inaccuracies or omissions. Applications information in this manual is intended as suggestions for possible use of the products and not as explicit performance in a specific application.
Warranty CHAPTER 1 CHAPTER 2 CHAPTER 3 CHAPTER 4 CHAPTER 5 CHAPTER 6 CHAPTER 7 CHAPTER 8 CHAPTER 9 Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Appendix G Appendix H TABLE OF CONTENTS 4 Getting Started Default Mode 1-1 Quick Hook-Up 1-2 Functional Description Block Diagram 2-4 Communications Data Format 3-2 RS-232 3-2 Multi-party Connection 3-3 Software Considerations 3-4 Changing Baud Rate 3-5 Using a Daisy-Chain With a Dumb Terminal RS-485 3-6 RS-485 Multidrop System 3-8 Command
WARRANTY DGH warrants each D1000 and D2000 series module to be free from defects in materials and workmanship under normal conditions of use and service and will replace any component found to be defective, on its return to DGH, transportation charges prepaid within one year of its original purchase. DGH assumes no liability, expressed or implied, beyond its obligation to replace any component involved. Such warranty is in lieu of all other warranties expressed or implied.
Chapter 1 Getting Started Default Mode All D1000 modules contain an EEPROM (Electrically Erasable Programmable Read Only Memory) to store setup information and calibration constants. The EEPROM replaces the usual array of switches and pots necessary to specify baud rate, address, parity, etc. The memory is nonvolatile which means that the information is retained even if power is removed. No batteries are used so it is never necessary to open the module case.
Getting Started 1-2 values. In most cases, a module in Default Mode may not be used in a string with other modules. RS-232 & RS-485 Quick Hook-Up Software is not required to begin using your D1000 module. We recommend that you begin to get familiar with the module by setting it up on the bench. Start by using a dumb terminal or a computer that acts like a dumb terminal. Make the connections shown in the quick hook-up drawings, Figures 1.1 or 1.2.
Getting Started 1-3 Figure 1.2 RS-485 Quick Hook-Up. RS-485 Quick Hook-up to a RS-232 port An RS-485 module may be easily interfaced to an RS-232C terminal for evaluation purposes. This connection is only suitable for benchtop operation and should never be used for a permanent installation. Figure 1.3 shows the hook-up. This connection will work provided the RS-232C transmit output is current limited to less than 50mA and the RS-232C receive threshold is greater than 0V.
Getting Started 1-4 Figure 1.3 RS-485 Quick Hook-Up with RS-232C Port.
Chapter 2 Functional Description A functional diagram of a typical module is shown in Figure 2.1. It is a useful reference that shows the data path in the module and to explain the function of many of the module’s commands. The first step is to acquire the sensor signal and convert it to digital data. In Figure 2.1, all the signal conditioning circuitry has been lumped into one block, the analog/digital converter (A/D). Autozero and autocalibration is performed internally and is transparent to the user.
Functional Description 2-2 undesired signal such as a tare weight. The Trim Zero (TZ) command is used to adjust the output to any desired value by loading the appropriate value in the offset register. The offset register data is nonvolatile. The output offset may also be modified using the Set Point (SP) command. The data value specified by the SP command is multiplied by -1 before being loaded into the register. The Set Point command specifies a null value that is subtracted from the input data.
Functional Description 2-3 Latching alarms are turned off with the Clear Alarms (CA) command or if the opposite alarm limit is exceeded. The state of the alarms may be read with the Digital Input (DI) command. Also, the alarm outputs may be used to activate digital outputs on the module to turn on alarms or to perform simple control functions. The alarm outputs are shared with the general purpose digital output bits DO0 and DO1.
Functional Description 2-4
Chapter 3 Communications Introduction The D1000 modules has been carefully designed to be easy to interface to all popular computers and terminals. All communications to and from the modules are performed with printable ASCII characters. This allows the information to be processed with string functions common to most high-level languages such as BASIC. For computers that support RS-232C, no special machine language software drivers are necessary for operation.
Communications 3-2 an improper command prompt or address is transmitted. The table below lists the timeout specification for each command: Mnemonic Timeout DI,DO,RD ND All other commands 10 mS See text 100 mS Table 3.1 Response Timeout Specifications. The timeout specification is the turn-around time from the receipt of a command to when the module starts to transmit a response. Data Format All modules communicate in standard NRZ asynchronous data format.
Communications 3-3 Figure 1.1 shows the connections necessary to attach one module to a host. Use the Default Mode to enter the desired address, baud rate, and other setups (see Setups). The use of echo is not necessary when using a single module on the communications line. Multi-party Connection RS-232C is not designed to be used in a multiparty system; however the D1000 modules can be daisy-chained to allow many modules to be connected to a single communications port.
Communications 3-4 inherent in its structure. The daisy-chain is a series-connected structure and any break in the communications link will bring down the whole system. Several rules must be observed to create a working chain: 1. All wiring connections must be secure; any break in the wiring, power, ground or communications breaks the chain. 2. All modules must be plugged into their own connectors. 3. All modules must be setup for the same baud rate. 4. All modules must be setup for echo.
Communications 3-5 if four modules are used in a chain operating at 1200 baud, the accumulated delay time is 4 X 8.33 mS = 33.3 mS This time must be added to the times listed in Table 3.1 to calculate the correct communications time-out error. For modules with RS-232C outputs, the programmed communications delay specified in the setup data (see Chapter 5) is implemented by sending a NULL character (00) followed by an idle line condition for one character time.
Communications 3-6 RS-485 RS-485 is a recently developed communications standard to satisfy the need for multidropped systems that can communicate at high data rates over long distances. RS-485 is similar to RS-422 in that it uses a balanced differential pair of wires switching from 0 to 5V to communicate data. RS-485 receivers can handle common mode voltages from -7V to +12V without loss of data, making them ideal for transmission over great distances.
Communications 3-7
Communications 3-8 RS-485 Multidrop System Figure 3.2 illustrates the wiring required for multiple-module RS-485 system. Notice that every module has a direct connection to the host system. Any number of modules may be unplugged without affecting the remaining modules. Each module must be setup with a unique address and the addresses can be in any order. All RS-485 modules must be setup for no echo to avoid bus conflicts (see Setup).
Communications 3-9 becomes an important consideration. The GND wire is used both as a power connection and the common reference for the transmission line receivers in the modules. Voltage drops in the GND leads appear as a common-mode voltage to the receivers. The receivers are rated for a maximum of -7V. of common-mode voltage. For reliable operation, the common mode voltage should be kept below -5V.
Chapter 4 Command Set The D1000 modules operate with a simple command/response protocol to control all module functions. A command must be transmitted to the module by the host computer or terminal before the module will respond with useful data. A module can never initiate a communications sequence. A variety of commands exists to exploit the full functionality of the modules. A list of available commands and a sample format for each command is listed in Table 4.1.
Command Set 4-2 Data Structure Many commands require additional data values to complete the command definition as shown in the example commands in Table 4.1. The particular data necessary for these commands is described in full in the complete command descriptions. The most common type of data used in commands and responses is analog data. Analog data is always represented in the same format for all models in the D1000 series.
Command Set 4-3 appears when large data values saved in the module’s EEPROM are read back. In most practical applications, the problem is non-existent. Overload values of analog data are +99999.99 and -99999.99 . Data read back from the Event Counter with the Read Events (RE) command is in the form of a seven-digit decimal number with no sign or decimal point. Round-off errors do not occur on the event counter.
Command Set 4-4 following the ‘ * ‘ prompt. The response format of all commands may be found in the detailed command description. The maximum response message length is 20 characters. A command/response sequence is not complete until a valid response is received. The host may not initiate a new command until the response from a previous command is complete. Failure to observe this rule will result in communications collisions.
Command Set 4-5 the two extra characters and assumes that it is a checksum. If the checksum is not present, the module will perform the command normally. If the two extra characters are present, the module calculates the checksum for the message. If the calculated checksum does not agree with the transmitted checksum, the module responds with a ‘BAD CHECKSUM’ error message and the command is aborted. If the checksums agree, the command is executed.
Command Set 4-6 The checksum is the two characters preceding the CR: A4 Add the remaining character values: * 1 R D + 0 0 0 7 2 . 1 0 2A + 31 + 52 + 44 + 2B + 30 + 30 + 30 + 37 + 32 + 2E + 31 + 30 = A4 The two lowest-order hex digits of the sum are A4 which agrees with the transmitted checksum. The transmitted checksum is the character string equivalent to the calculated hex integer. The variables must be converted to like types in the host software to determine equivalency.
Command Set 4-7 EC HI ID LO PT RR SU SP TS TZ WEA Events Read & Clear Set High Alarm Limit IDentification Set Low Alarm Limit Pulse Transition Remote Reset Setup Module Set Setpoint Trim Span Trim Zero Write Extended Address $1EC $1HI+12345.67L $1ID BOILER $1LO+12345.67L $1PT+$1RR $1SU31070142 $1SP+00600.00 $1TS+00600.00 $1TZ+00000.
Command Set 4-8 or SetPoint (SP) command. Command: Response: $1CZ * Command: Response: #1CZ *1CZF8 Disable Alarms (DA) Most D1000 modules feature LO/DO0 and HI/DO1 pins on the module connector. These pins serve a dual function and can be used to output either the alarm outputs or digital outputs 0 and 1. The Disable Alarms command is used to connect the digital outputs 0 and 1 to the connector pins.
Command Set 4-9 For example: A typical response from a $1DI command could be: *01FE. This response indicates that the HI alarm is off, the LO alarm is on, DI0 = 0 and all other digital inputs are = 1 All digital inputs that are not implemented or left unconnected are read as ‘1’ Digital input 0 serves a dual function. It is both a digital input and the Event Counter input. When reading digital inputs with a checksum, be sure not to confuse the checksum with the data.
Command Set 4-10 Enable Alarms (EA) Digital outputs DO0/LO and DO1/HI serve a dual purpose as both digital outputs and alarms. Digital output 0 is shared with the LO alarm and digital output 1 is shared with the HI alarm. The Enable Alarms (EA) command configures the shared outputs to indicate alarm conditions and disconnects digital outputs 0 and 1. The EA command only affects the electrical output of the alarms to the pins. The alarm status can be read at any time with the Digital Input (DI) command.
Command Set 4-11 The alarm limit should be set within the output range of the module. If the alarm limit is set beyond the output range, the alarm will be activated only on an overload condition. The high alarm value may be read back with the Read High Alarm (RH) command. A latched alarm may be cleared with the Clear Alarms (CA) command. More information on alarms may be found in Chapter 6.
Command Set 4-12 The low limit value may be read back with the Read Low Limit (RL) command. More information on alarms may be found in Chapter 6. New Data Command (ND) The New Data (ND) command is a variation of the Read Data (RD) command used to read sensor data from the module. The ND command guarantees that the output data has not been previously read. The D1000 module acquires analog input data eight times a second and stores the result in the output buffer (see Figure 2.1).
Command Set 4-13 Pulse Transition (PT) The Pulse Transition command is used on Frequency and Timer input modules. It is used to set the direction of the edge used to trigger the measurement cycle. There are four possible edge transitions: (+ to -), (- to +), (- to -), (+ to +). For example: Command: Response: $1PT+ * Command: #1PT Response: *1PT+ -50 Read Data (RD) The read data command is the basic command used to read the buffered sensor data. The output buffer (Figure 2.
Command Set 4-14 The Remote Reset (RR) command or a line break does not effect the value of the Event Counter. When reading the Event Counter with a checksum, be sure not to confuse the checksum with the data. Read Extended Address (REA) The Read Extended Address is used to read back two character address stored by the Extended Address (EA) command.
Command Set 4-15 Read Low Alarm (RL) The Read Low alarm command reads the value and type of the low alarm. The alarm type can be either latching or momentary. A letter indicating the alarm type, “L” for latching or “M” for momentary, will follow the alarm value. For example: Command: Response: Command: $1RL *+00000.00L #1RL Response: *1RL+00000.00LEE The RL command may be used to verify data loaded into the nonvolatile memory with the LO command.
Command Set 4-16 Read Setup (RS) The read setup command reads back the setup information loaded into the module’s nonvolatile memory with the SetUp (SU) command. The response to the RS command is four bytes of information formatted as eight hex characters. Command: Response: $1RS *31070142 Command: Response: #1RS *1RS3107014292 The response contains the module’s channel address, baud rate and other parameters.
Command Set 4-17 To clear a setpoint, use the Clear Zero (CZ) command. The SP command writes over data written into the Output Offset Register by the Trim Zero (TZ) command. If the Output Offset Register is used as a trim value, this must be accounted for by the host before using the SP command. The value stored in this register may be read back using the Read Zero (RZ) command. The setpoint data or trim data in the Output Offset Register is saved in nonvolatile memory.
Command Set 4-18 Caution! TS is the only command associated with the span trim. There is no provision to read back or clear errors loaded by the TS command. Misuse of the TS command may destroy the calibration of the unit which can only be restored by using laboratory calibration instruments in a controlled environment. An input signal must be applied when using this command. Trim Zero (TZ) The Trim Zero command is used to load a value into the Output Offset Register (Figure 2.
Command Set 4-19 The SetPoint (SP) command will write over any value loaded by the TZ command. Write Enable (WE) Each module is write protected against accidental changing of alarms, limits, setup, or span and zero trims. To change any of these write protected parameters, the WE command must precede the write-protected command. The response to the WE command is an asterisk indicating that the module is ready to accept a write-protected command.
Command Set 4-20 ERROR MESSAGES The D1000 modules feature extensive error checking on input commands to avoid erroneous operation. Any errors detected will result in an error message and the command will be aborted. All error messages begin with “?”, followed by the channel address, a space and error description. The error messages have the same format for either the ‘ $ ‘ or ‘ # ‘ prompts. For example: ?1 SYNTAX ERROR There are eight error messages, and each error message begins with a different character.
Command Set 4-21 to ensure proper operation of the microprocessor. The timer may be tripped if the microprocessor is executing its program improperly due to power transients or static discharge. If the NOT READY error persists for more than 30 seconds, check the power supply to be sure it is within specifications. PARITY ERROR A parity error can only occur if the module is setup with parity on (see Setup). Usually a parity error results from a bit error caused by interference on the communications line.
Chapter 5 Setup Information/SetUp Command The D1000 modules feature a wide choice of user configurable options which gives them the flexibility to operate on virtually any computer or terminal based system. The user options include a choice of baud rate, parity, address, and many other parameters. The particular choice of options for a module is referred to as the setup information. The setup information is loaded into the module using the SetUp (SU) command.
Setup & SetUp Command 5-2 Command Syntax The general format for the SetUp (SU) command is: $1SU[byte1][byte 2][byte 3][byte 4] A typical SetUp command would look like: $1SU31070182. Notice that each byte is represented by its two-character ASCII equivalent. In this example, byte 1 is described by the ASCII characters ‘31’ which is the equivalent of binary 0011 0001 (31 hex). The operand of a SU command must contain exactly 8 hex (0-F) characters. Any deviation from this format will result in a SYNTAX ERROR.
Setup & SetUp Command 5-3 When using the SU command to change the address of a module, be sure to record the new address in a place that is easily retrievable. The only way to communicate with a module with an unknown address is with the Default Mode. The most significant bit of byte 1 (bit 7) must be set to ‘0’. In addition, there are six ASCII codes that are illegal for use as an address. These codes are $00, $0D, $24, $23, $7B, $7D which are ASCII codes for the characters NUL, CR, $, #, { and }.
Setup & SetUp Command 5-4 Byte 2 Byte 2 is used to configure some of the characteristics of the communications channel; linefeeds, parity, and baud rate. Linefeeds The most significant bit of byte 2 (bit 7) controls linefeed generation by the module. This option can be useful when using the module with a dumb terminal. All responses from the D1000 are terminated with a carriage return (ASCII $0D). Most terminals will generate a automatic linefeed when a carriage return is detected.
Setup & SetUp Command 5-5 changing the baud rate of an RS-232C string. For more information on changing baud rate, refer to Chapter 3. Let’s run through an example of changing the baud rate. Assume our sample module contains the setup data value of ‘31070080’. Byte 2 is ‘07’. By referring to the SU command chart we can determine that the module is set for no linefeeds, no parity, and baud rate 300.
Setup & SetUp Command 5-6 responds. The last resort is to set the module to Default Mode where the baud rate is always 300. Setting a string of RS-232C modules to a new baud rate requires special consideration. Refer to Chapter 3 for instructions. Bit 4 Bit 4 is used to enable or disable extended addressing mode. Table 5.2 Byte 2: Linefeed, Parity, Addressing and Baud Rate.
Setup & SetUp Command 5-7 High Alarm Latch Bit 5 determines whether the HI Alarm is latching or momentary. A’1' indicates latching. Bit 5 is also controlled individually by the HI Alarm (HI) command. Disable CJC RTD 3/4 Wire Trigger Edge Select The setup information stored in bit 4 has different meanings depending on the D1000 model number. Disable CJC; this function pertains only to the D1300 series of thermocouple input modules. If the bit is set to ‘1’ the Cold Junction Compensation is disabled.
Setup & SetUp Command 5-8 delay is added to the typical command delays listed in the Software Considerations section of Chapter 3. Each unit of delay specified by bits 0 and 1 is equal to the amount of time required to transmit one character with the baud rate specified in byte 2. For example, one unit of delay at 300 baud is 33.3 mS; for 38.4 kilobaud the delay is 0.26 mS. The number of delay units is selectable from 0 to 6 as shown in Table 5.3.
Setup & SetUp Command 5-9 Byte 4 This setup byte specifies the number of displayed digits and the digital filter time constants. Number of displayed digits For ease of use, the data outputs of all modules are standardized to a common 7-digit output consisting of sign, 5 digits, decimal point, and two more digits. Typical output data looks like: +00100.00. However, best-case resolution of the A/D converter is 1 part in 32,768.
Setup & SetUp Command 5-10 filter constant after every A/D conversion. The constant selected depends on the magnitude of the change of the input signal and the setup for the number of digits displayed. The microprocessor always keeps the value of the last calculated output to compare to a new data conversion. If the new data differs from the last output by more than ten counts of the last displayed digit, the large signal time constant is used in the digital filter.
Setup & SetUp Command 5-11 Small Signal Time Constant Bits 0,1, 2 specify the filter time constant for small signals. Its values are similar to the ones for the large signal filter. Most sensors can benefit from a small amount of small signal filtering such as T = 0.5 seconds In most applications, the small signal time constant should be larger than the large signal time constant. This gives stable readings for steady-state inputs while providing fast response to large signal changes. Table 5.
Setup & SetUp Command 5-12 to echo so that it may be used in a daisy-chain (See Communications). Read out the current setup with the Read Setup command: Command: Response: $1RS *310701C2 By referring to Table 5.3, we find that the echo is controlled by bit 2 of byte 3. From the RS command we see that byte 3 is currently set to 01. This is the hexadecimal representation of binary 0000 0001. To set echo, bit 2 must be set to ‘1’. This results in binary 0000 0101. The new hexadecimal value of byte 3 is 05.
Chapter 6 Digital I/O Functions The D1000 series features versatile digital I/O capability to interface to auxiliary equipment. The functions available are: 1) Digital Outputs 2) Digital Inputs 3) Alarm Outputs 4) Events Counter Digital Outputs A digital output consists of an open-collector transistor controlled by the host, using the Digital Output (DO) command (See Figure 6.1). The number of digital outputs implemented depends on the specific D1000 model number.
Digital I/O Functions 6-2 connection to a logic input is shown in Figure 6.2. In some cases, the common-mode voltage of the GND terminal may be significantly different from the ground potential of the logic input to be interfaced. This may occur when the module is powered remotely. In this case, an opto-isolator may be used to eliminate the common-mode voltage. See Figure 6.2. In all cases, the current switched by the transistor may not be more than 30mA. Only three commands can effect the Digital Output.
Digital I/O Functions 6-3 Digital inputs are used to sense switch closures and the state of digital signals. The inputs are protected to voltages up to ±30V and are normally pulled up to the logic “1” condition (see Figure 6.3). Digital inputs can be read by the Digital Input (DI) command. Voltage inputs less than 1 V are read back as ‘0’. Signals greater than 3.5 V are read as ‘1’. No other commands have any affect on the inputs.
Digital I/O Functions 6-4 The Event Counter is read by using the Read Events (RE) command. The maximum accumulated count is 9,999,999. If the maximum count is reached, counting stops. The Event Counter may be cleared to zero with the Clear Events (CE)or Events Read & Clear (EC) command. The Event Counter is not nonvolatile and the count will be lost if power to the module goes down. Upon power up, the counter is cleared to zero. The Remote Reset (RR) command or a line break will not affect the counter.
Digital I/O Functions 6-5 Alarm limit values are loaded into the module with the Low limit (LO) and Hi limit (HI) commands. The limit values are stored in nonvolatile memory so they will not be lost when power is removed. The HI and LO commands are also used to specify whether the alarms are momentary or latching. If an alarm is specified as momentary, the alarm is activated as long as the alarm condition exists. The alarm output will turn off when the input is within limits.
Digital I/O Functions 6-6 Figure 6.5 On-Off Controller ON-OFF CONTROLLER WITH HYSTERESIS The simple single-value controller, by its very nature, suffers from erratic output that may not be acceptable, particularly when high-power equipment is being controlled. To lengthen the control cycle and to make the control action smoother, hysteresis (dead band) is often used in on-off controllers.
Digital I/O Functions 6-7 The high and low alarm limits on the D1000 sensor modules may be set to provide on-off control with hysteresis. The two limits specify the two control setpoints. The difference between the high limit and the low limit is the hysteresis value. The high limit must be greater than the low limit for proper operation. The alarm output used to control the process must be set to the Latching mode.
Digital I/O Functions 6-8
Digital I/O Functions 6-9 SETPOINT In the preceding example, the low and high alarm limits are used to specify a hysteresis value around a desired setpoint. To change the desired setpoint, both the low and high alarm values must be changed. In this type of controller operation, the Read Data (RD) or New Data (ND) commands will read out the actual value of the process variable.
Digital I/O Functions 6-10 The benefit of using SP command is that only one command is necessary to change the setpoint value. The hysteresis is stored in the HI and LO alarm registers and does not have to be changed when a new setpoint is used. The SP command makes it particularly easy to construct a controller whose setpoint is a time varying function downloaded from a host computer. The SP command can also be used without control functions whenever a deviation output is desired.
Chapter 7 Power Supply D1000 modules may be powered with an unregulated +10 to +30Vdc. Power-supply ripple must be limited to 5V peak-to-peak, and the instantaneous ripple voltage must be maintained between the 10 and 30 volt limits at all times. The modules contain a low voltage detection circuit that shuts down all circuits in the module at approximately 9.5 Vdc.
Chapter 8 Troubleshooting Symptom: RS-232 Module is not responding to commands RS-485 Module is not responding to commands Events counter not counting properly. Error in displayed value. Read Data (RD) values are factor of two times normal values. Module responds with ?1 COMMAND ERROR to every command. Characters in each response message appear as graphics characters • RS-232 Module is not responding to commands 1.
• RS-485 Module is not responding to commands 1. Perform steps 1, 2, 4, 5 and 6 listed above. 2. Ensure that module RS-485 "Data" line (module terminal pin #7) is connected to the Host RS-485 "Data+" line. 3. Ensure that module RS-485 "Data*" line (module terminal pin #8) is connected to the Host RS-485 "Data-" line. 4. If the problem is not corrected after completing the steps above then connect the module by itself to a Host computer as outlined in Chapter 1.0 under "Quick Hook-up".
Chapter 9 Calibration The D1000 module is initially calibrated at the factory and has a recommended calibration interval of one year. Calibration constants are stored in the EEPROM and may be trimmed using the Trim Span (TS) and Trim Zero (TZ) commands. There are no pots to adjust. Calibration procedure is as follows. Voltage and current inputs: clear the output offset register using the Clear Zero (CZ) command. Zero trims are not neccessary due to the built-in autozero function.
Calibration 9-2 This sequence will trim the output to +00900.00. Verify: Command: Response: $1RD *+00900.00 The module is calibrated. Thermocouples: Disable the cold junction compensation by setting bit 4 in byte 3 of the setup data with the SetUp (SU) command. The module may now be calibrated using a known input voltage. Perform the calibration as described for a voltage input module. Table 9.1 gives recommended calibration points.
Calibration 9-3 Table 9.1 Calibration Values Model D110X D111X D112X D113X D114X D115X D121X D122X D123X D124X D125X D131X D132X D133X D134X D135X D136X D137X D138X D141X D142X D143X D145X D146X D151X D152X D153X D154X D155X D156X D160X D161X D163X D164X Input Stimulus +9000µV +90mV +900mV +4.5V +9V +90V +9000µA +900µA +90mA +900mA +20mA +39.13mV +41.269mV +17.816mV +68.783mV +17.445mV +15.576mV +10.094mV +33.442mV 300.00Ω 300.00Ω 134.91Ω 206.1Ω 3018Ω 25mV 25mV 90mV 90mV 5.5V 5.
Chapter 10 Extended Addressing The D1000 may be configured to a special command format called Extended Addressing. This mode uses a different prompt, either '{' or '}' to distinguish it from the regular command syntax. The major difference in syntax for the Extended Addressing mode is that it uses a two-character address. A typical command in Extended Address mode would look like this: Command: Response: {01WE * Both the command and response are terminated with carriage returns.
The Extended Address commands use a two-character ASCII address, each character may be one of 122 legal possibilities. Illegal characters are: NULL ($00), CR ($0D), $ ($24), # ($23), { ($7B), and } ($7E).
Appendix A ASCII Table Table of ASCII characters (A) and their equivalent values in Decimal (D), Hexadecimal (Hex), andBinary.Claret (^) represents Control function.
A # $ % & ‘ ( ) * + , .
A L M N O P Q R S T U V W X Y Z [ \ ] ^ _ ‘ a b c d e f g h i j k l m n o p q r s t D 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 Hex 4C 4D 4E 4F 50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F 60 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F 70 71 72 73 74 Binary 01001100 01001101 01001110 01001111 01010000 01010001 01010010 01010011 01010100 01010101 01010110 01010111 01011000 01011001 01011010 01011011 01011
A u v w x y z { | } ~ D 117 118 119 120 121 122 123 124 125 126 127 Hex 75 76 77 78 79 7A 7B 7C 7D 7E 7F Binary 01110101 01110110 01110111 01111000 01111001 01111010 01111011 01111100 01111101 01111110 01111111 D 245 246 247 248 249 250 251 252 253 254 255 Hex F5 F6 F7 F8 F9 FA FB FC FD FE FF ASCII Tables A-4 Binary 11110101 11110110 11110111 11111000 11111001 11111010 11111011 11111100 11111101 11111110 11111111
Appendix B D1600 Data Sheet The Frequency and Timer Input modules feature a versatile input stage that can be used in a variety of applications. Figure 1 is a block diagram of the input signal conditioning. Figure B-1. D1601/2 Input Signal Conditioning Block Diagram. The input signal is applied to a precision comparator through the + input. Input protection is provided to withstand inputs up to 230Vac.
D1600 Data Sheet B-2 R Vswitching ± Vhysteresis Open 2.5V ± 0.5V ØΩ 2.5V ± 5mV For Vhysteresis >5mV and <0.5V: 34 Vhysteresis R (in KΩ) = 0.5 -Vhysteresis Figure B-2. Controlling Hysteresis For Positive-Going Signals This connection is used for unipolar positive-going frequency signals. The hysteresis is centered around a +2.5V switching level. If R is left open, the switching levels are +3V and +2V, or 2.5V ±0.5V. If R is shorted, the hysteresis decreases with resulting switching levels of 2.
D1600 Data Sheet B-3 Figure B-3. Controlling Hysteresis For Bipolar Signals. R Open ØΩ Vswitching ± Vhysteresis 2.5V ± 0.5V 1.7V ± 5mV For Vhysteresis >5mV and <0.5V: 34 Vhysteresis R (in KΩ) = 0.5 - Vhysteresis Vswitching = 2.5 - 14 17 + R Figure B-4. Controlling Switching Level and Hysteresis. The hysteresis control may also be connected to ground (GND), which produces another set of switching levels. This connection is shown in figure B-4.
D1600 Data Sheet B-4 module contains an internal 1MΩ resistor connected from the +IN to +2.5V for biasing. A .01 uf cap may be used for frequencies down to 10HZ. D1630/D1640 Accumulator Modules Figure B-5. Accumulator Block Diagram. The Accumulator models are: D1631, D2631, D1632, D2632, D1641, D2641, D1642 and D2642 are designed for applications that require reading and accumulating pulse type information.
D1600 Data Sheet B-5 Event Counter The Event Counter input is connected to the Digital Input 0 terminal. It can be used to count any low speed event that occurs on the DIØ/EV input. Any of the interfacing techniques described for Digital Inputs may be used. The input pulses must meet the specifications in Figure 6.4 to avoid missing counts. Switch inputs are filtered to eliminate contact bounce. The Event Counter is read by using the Read Events (RE) command. The maximum accumulated count is 9,999,999.
Appendix C D1400 Data Sheet SPECIFICATIONS: (Typical @ 25°C, V+ = +15V) RTD Types: =.00385, .00388, .00392 100Ω @ 0°C Resolution: 0.1° Accuracy: ±0.3°C Input connections: 2, 3, or 4 wire Excitation current: .25 mA Max. Lead resistance: 50Ω Input protection to 120Vac Automatic linearization and lead compensation User selectable °C or °F Lead resistance effect: 3 wire—2.
4-Wire: For 4-wire operation, connect the RTD as shown in the diagram. If the RTD has heavy excitation wires, they should be connected to the +I and -I terminals. For proper 4-wire operation, the RTD set-up bit must be set to 1 (see Set-Up (SU) command). A typical set-up for 4-wire operation would be 31071182. Figure C-2. 4-Wire RTD Configuration. 2-Wire: The 2-wire connection requires two jumpers on the connector (J1 & J2) as shown in the diagram. This connection provides no lead compensation.
Appendix D D1500 Data Sheet The D1500 Bridge Sensor Interface Modules contain all of the signal conditioning functions necessary to interface Strain Gage and other resistive bridge devices to an RS-232C or RS-485 computer port. Each module contains excitation, an instrumentation amplifier, and a smart analog to digital converter to convert resistive bridge sensor signals to ASCII data.
D1500 Data Sheet D-2 Figure D-1 Bridge Circuit Wiring To perform an initial offset trim, attach the bridge unit to the module (as shown in Figure 1). Clear out any previous offset trims with the Clear Zero (CZ) command. Apply the desired zero condition to the bridge sensor. For a Strain Gage Bridge this would be the relaxed or unstrained condition. For load cells, the zero condition could include any tare weight due to a weighing platform or other attachments that would affect the zero balance.
D1500 Data Sheet D-3 Figure D-2 Bridge Circuit Trim Example 1: A load cell to be used in a weighing application is mated to a D1521 module. Theloadcellisratedfor3mV/V,whichresultsinamaximum ±30mVwith10V excitation. However, in this application, the load cell is used only in tension so its ideal output will be from 0 to +30mV. The load cell is mounted in position with the weighing attachments.
D1500 Data Sheet D-4 The initial offset is +2.34mV. The D1521 has a useful input range of ±60mV. Aftersubtractingtheoffsetthe“inputoverhead”is-62.34mVand+57.66mV. The expected 0 to +30mV output of the load cell easily falls within the overhead range and no external trimming is necessary. To Trim Zero: Command: Response: $1WE * (TZ is write protected) Command: Response: $1TZ+00000.00 * (zero output) Now read the data output to verify the trim: Command: Response: $1RD (Read Data) *+00000.
D1500 Data Sheet D-5 This value is within the ±30mV offset necessary to provide enough headroom for the strain gage bridge. Trim out the remaining offset with the Trim Zero (TZ) command: Command: Response: $1WE * Command: Response: $1TZ+00000.00 * The bridge is now trimmed to zero. Verify: Command: Response: $1RD * +00000.00 The Trim Zero (TZ) command may be used at any time to balance out offsets due to temperature, residual stress, tare, etc.
D1500 Data Sheet Figure D-3 D1500 Calibration Step 1: power up the unit under test and let it warm up for at least two minutes. Step 2: set the voltage source to 0 volts (short). Perform a TZ+00000.00 (Trim Zero) command to eliminate any common-mode offset errors. Step3:measuretheexcitationvoltagewiththeDVM.Dividetheresultbythe nominal excitation voltage, either 10V or 5V, to obtain a “compensation factor” = CF. Step 4: calculate the correct calibration voltage to apply to the unit.
D1500 Data Sheet Calibration Example: We wish to calibrate a D1511 module. This unit contains 5V excitation and a ±30mVinput. Step 1 is straightforward and needs no further explanation. Step 2: set the voltage source to 0 volts. Trim zero: Command: Response: $1WE * Command: Response: $1TZ+00000.00 * Step 3: measure the excitation voltage with the DVM. In this example the measured voltage is 4.954V Calculate the “compensation factor”: CF = 4.954 / 5 = 0.
D1500 Data Sheet Tospecifycontinuousoutput,adda“C”suffixtothemodelnumber;D1511C for example. Programmable Scaling The D2500 series of interface modules are bridge units similar to the D1500 seriesexceptthattheinput/outputtransferfunctionmaybeprogrammedby the user. Output data may be scaled to any desired engineering units such as pounds, psi, Newtons, etc. Nonlinear functions may also be programmed into the module. All scaling data is stored in nonvolatile memory and may be reprogrammed any number of times.
Appendix E D2000 Series The D2000 series is an enhancement of the D1000 series. As shipped from the factory, the D2000 modules operate in the same manner as their D1000 counterparts. For example, a D2111 shipped from the factory contains the same transfer function as a D1111 module; in this case they are both ±100 mV inputs and communicate with RS-232C. Before any attempt is made to program a D2000, you must first be familiar with the operation of a D1000 module as described in this manual.
Appendix F D1000/2000 Continuous Operation All D1000/2000 computer interface modules may be factory-configured to provide continuous output of analog input data. A D1000/2000 continuous module is intended for applications where no host computer is present. The limitation to the continuous mode is that only one module can be on the communications line. Continuous output may be ordered by adding a “C” suffix to the model number.
Continuous Operation F-2 For dedicated output-only applications the RECEIVE input of RS-232 modules serves no purpose and may be disconnected to eliminate one wire connection to the host. In this case, be sure to connect the RECEIVE input to GND to prevent a line break condition. In continuous mode, a module will output data after every A/D conversion, or approximately eight times a second. For baud rates of 300 and 600, the repetition rate is limited by the time required for communications.
Continuous Operation F-3 execute the S1000 utility software (filename = 100030.exe). At the main menu, select HOST and specify the correct serial computer port. All remaining host values should not have to be changed. Press key and return to main menu when port selection is complete. Step 2. Select main menu “SETUP” and enter a module address and model number. If the module “DEFAULT*” pin is grounded (connected to GND terminal) then enter address “1” and press .
Continuous Operation F-4 Install/Test the configuration The module setup modifications are complete. Both modules may now be bench tested or installed into the final application. The module power supply and communications connections should be straight forward during installation. Make sure that the “DEFAULT*” pin on each module IS NOT connected to ground. For proper “continuous” operation, another pin on each module MUST BE connected to ground.
Appendix G RTS Operation The D1000R/2000R series analog input modules interface to radio and leased telephone line modems. Many of these modems require an RS-232 signal to activate, or “key-up”, the transmitter. They also require adequate delay time for the transmitter to turn on before transmitting data. The amount of delay time required varies between modem types and manufacturers. Typical time periods range from 150ms for leased line modems to 500ms for radio modems.
RTS Operation G-2 be specified using the standard data format ‘+#####.##’. Use the write protected commands T1, T2 and T3 to specify the delay time values. The RTS output function is activated using the RTS+ or RTS- commands. The + and - polarity characters determine the active polarity of the RTS signal while data is being transmitted. The signal polarity can be either active high (typically +Vs) or low (zero volts).
RTS Operation G-3 The RTS output and the delay time values are disabled while in Default Mode. The RTS output is located on digital output bit 0 (DO0/RTS). The digital output is an open-collector transistor and will require an external pull-up resistor. The external pull-up may be eliminated if a module contains one unused digital input bit. All D1000R/2000R series digital input bits contain an internal 10K ohm pull-up resistor to +5Vdc. Simply connect the DO0/RTS terminal to the unused digital input.
RTS Operation G-4 The ID command is write protected and checksums are not supported. The module will abandon any ID command with a message length in excess of 16 characters. Command: Response: $1IDBOILER ROOM * Command: Response: #1IDBOILER ROOM *1IDBOILER ROOM02 Read IDentification (RID) The Read Identification (RID) command is used to read data previously stored by the ID command. The RID command response message length is variable depending on the stored message length.
RTS Operation G-5 Command: Response: #1RT2 *1RT2+00550.00E6 Read Time Delay 3 (RT3) The RT3 command is used to read the time delay value previously stored with the T3 command. The value returned is scaled in milliseconds and has a range of 0 to 2000ms. Command: Response: $1RT3 *+00035.00 Command: Response: #1RT3 *RT3+00035.00E5 Request-To-Send+ (RTS+) The RTS+ command enables the RTS output function and sets the active signal polarity to high (positive voltage).
RTS Operation G-6 The RTS- command is write protected and the polarity value is stored in EEPROM memory. Therefore, all subsequent power ups will activate the RTS- mode eliminating the need for software initialization. The RTS- mode will remain active until the module receives a RTSD command. NOTE: The RTS output function will override any alarm or digital output commands associated with digital output 0.
RTS Operation G-7 Command: Response: #1T1+00100.00 *1T1+00100.008A Set Time Delay 2 (T2) Time delay T2 is used to ensure adequate time is allowed for the modem transmitter to turn on before any data is transmitted. Delay T2 starts immediately after the RTS signal is enabled. Once T2 expires, RS-232 data will be transmitted thru the modem to the host computer. The amount of delay time required is hardware specific and can usually be found in the modem users manual.
RTS Operation G-8 The response to a WE command is an asterisk indicating that the module is ready to accept a write protected command. Once the write protected command is successfully completed, the module will automatically become write disabled. Each write protected command must be individually preceded by a WE command.
Appendix H D1000/2000 Specifications Specifications (typical @ +25° C and nominal power supply unless otherwise noted.) Analog • Single channel analog input. • Maximum CMV, input to output at 60Hz: 500V rms. • Leakage current, input to output at 115Vrms, 60Hz: <2µA rms. • 15 bit measurement resolution. • 8 conversions per second. • Autozero & autocalibration—no adjustment pots. Digital • 8-bit CMOS microcomputer. • Digital scaling, linearization and calibration.
Specifications H-2 • Parity: odd, even, none. • User selectable channel address. • ASCII format command/response protocol. • Up to 122 multidrop modules per host serial port. • Communications distance up to 4,000 feet (RS-485). • Transient suppression on RS-485 communications lines. • Communications error checking via checksum. • Can be used with "dumb terminal". • Scan up to 250 channels per second. • All communications setups stored in EEPROM. Power Requirements: Unregulated +10V to +30Vdc, 0.
Specifications H-3 D1300 Thermocouple Inputs • Thermocouple types: J, K, T, E, R, S, B, C (factory set). • Ranges: J = -200°C to +760°C B = 0°C to +1820°C K = -150°C to +1250°C S = 0°C to +1750°C T = -200°C to +400°C R = 0°C to +1750°C E = -100°C to +1000°C C = 0°C to +2315°C • Resolution: ±1°. • Overall Accuracy (error from all sources) from 0 to +40°C ambient: ±1.0 °C max (J, K, T, E). ±2.5 °C max (R, S, B, C)(300°C TO FS). • Common mode rejection: 100dB at 50/60Hz. • Input impedance: 100MΩ min.
• Accuracy: 2252Ω = ±0.1°C. TD = ±0.2°C • Common mode rejection: 100dB at 50/60Hz. • Input protection to 30Vdc . • User selectable °C or °F. • 1 Digital input/ Event counter, 2 Digital outputs. D1500/D2500 Bridge Inputs • Voltage Ranges: ±30mV, ±100mV, 1-6Vdc. • Resolution: 10µV (mV spans). 0.02% of FS (V span). • Accuracy: ±0.05% of FS max. • Common mode rejection: 100dB at 50/60Hz. • Input burnout protection to 30Vdc . • Offset Control: Full input range. • Excitation Voltage: 5V, 8V, 10Vdc, 60mA max.
• Input Timer Range: 100 µs to 30s. • Pulse Count: Up to 10 million positive transitions. • Resolution: 0.005% of reading +0.01Hz (Frequency). 0.005% of reading +10 µs (Timer) . •Accuracy: ±0.01% of frequency reading ±0.01Hz. ±0.01% of timer reading ±10µs. • Tempco: ±20ppm/°C. Specifications H-5 D1700 Digital Inputs/Outputs D1711, D1712: 15 digital input/output bits. • User can define any bit as an input or an output. • Input voltage levels: 0-30V without damage. • Input switching levels: High, 3.5V min.
