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D3000/4000 SERIES USERS MANUAL REVISED: 6/1/94 DGH CORPORATION P. O. BOX 5638 MANCHESTER, NH 03108 TELEPHONE: 603-622-0452 FAX: 603-622-0487 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.
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TABLE OF CONTENTS Warranty 4 CHAPTER 1 Getting Started Terminal Designations 1-1 Default Mode 1-2 Quick Hook-Up 1-3 CHAPTER 2 Functional Description Block Diagram 2-3 CHAPTER 3 Communications Data Format 3-2 RS-232C 3-2 Multi-party Connection 3-3 Software Considerations 3-4 Changing Baud Rate 3-5 RS-485 3-6 RS-485 Multidrop System 3-7 CHAPTER 4 Command Set Table of Commands 4-7 User Commands 4-8 Error Messages 4-24 CHAPTER 5 Setup Information and Command Command Syntax 5-2 Setup Hints 5-9 CHAPTER 6 Digit
WARRANTY DGH warrants each D3000 and D4000 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 Introduction The D3000/4000 series are completely self-contained computer-to-analog output interfaces. They are designed to be mounted remotely from a host computer and communicate with standard RS-232 and RS-485 serial ports. Simple ASCII commands are used to control a 12-bit DAC (Digital-to-Analog Converter) which is scaled to provide commonly used current and voltage ranges.
Getting Started 1-2 Pins 1 and 2 are electrically isolated from the other pins. Pin 3 Pin 4 Pin 5 DI2 DI1/UP* DI0/DN* Pins 3-5 are digital input pins. They may be used as general-purpose inputs or they may be set-up to provide special functions that control the analog output. The standard factory set-up configures the UP* and DN* pins to provide manual up and down control of the analog output. The * designation indicates that the labels are negative true.
Getting Started 1-3 settings. However, there is one minor drawback in using EEPROM instead of switches; there is no visual indication of the setup information in the module. It is impossible to tell just by looking at the module what the baud rate, address, parity and other settings are. It is difficult to establish communications with a module whose address and baud rate are unknown. To overcome this, each module has an input pin labeled DEFAULT*.
Getting Started 1-4 measure the signals from current-output modules, a sense resistor and a voltmeter may be used as shown in Fig. 1.1. Turn power on to the module. Momentarily ground the UP* pin on the connector. The output signal should increase in value as the UP* pin is held low. Now release the UP* pin and ground the DN* (down) pin. The output signal should decrease in value as the pin is held low. This demonstrates the “Manual Mode” method of controlling the output.
Getting Started 1-5 Figure 1.1 D3000/4000 RS-232C 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.
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Getting Started 1-7 Note: If using a DB-9 connector ground is tied to pin 5 only. Figure 1.3 D3000/4000 RS-485 Quick Hook-up with RS-232C Port. Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.
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Chapter 2 Functional Description The D3000/4000 Computer to Analog Output interfaces provide accurate analog process control signals in response to simple digital commands from a host computer. The D3000/4000 units are completely self-contained and are designed to be operated remotely from the host. Digital commands are transmitted to the D3000/4000 units using standard RS-232 or RS-485 communications links. Commands and responses are in the form of simple English ASCII character strings for ease of use.
Functional Description 2-2 D4000 models also feature a simple Analog to Digital Converter (ADC) which is used to monitor the output signal. The ADC input is tied directly to the analog output and converts the signal level to digital data. The digital data is optically isolated and may be read by the microprocessor. This circuitry allows the D4000 user to directly monitor the output signal and ensure its integrity. The last major block in the diagram is the power supply.
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Chapter 3 Communications Introduction The D3000/4000 modules have 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 highlevel languages such as BASIC. For computers that support RS-232C, no special machine language software drivers are necessary for operation.
Communications 3-2 time-out error has occurred. After the communications time-out it is assumed that no response data is forthcoming. This error usually results when an improper command prompt or address is transmitted. The table below lists the timeout specification for each command: Mnemonic Timeout DI, HX, WE ID All other commands 3mS 130mS 35 mS Table 3.1 Response Timeout Specifications.
Communications 3-3 Single Module Connection 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 D3000/4000 modules can be daisy-chained to allow many modules to be connected to a single communications port.
Communications 3-4 The daisy chain network must be carefully implemented to avoid the pitfalls 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 connectors. 3.
Communications 3-5 is equal to the time necessary to retransmit one character using the baud rate setup in the module: Baud Rate 300 600 1200 2400 4800 9600 19200 38400 Delay 33.30mS 16.70mS 8.33mS 4.17mS 2.08mS 1.04mS 520µS 260µS One delay time is accumulated for each module in the chain. For example, 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.
Communications 3-6 result of the new baud rate. Using A Daisy-Chain With A Dumb Terminal A dumb terminal can be used to communicate to a daisy-chained system. The terminal is connected in the same manner as a computer used as a host. Any commands typed into the dumb terminal will be echoed by the daisy chain. To avoid double characters when typing commands, set the terminal to full duplex mode or turn off the local echo. The daisy chain will provide the input command echo.
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Communications 3-8 on one serial communications port. 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 form of all commands to detect transmission errors. In situations where many modules are used on a long line, voltage drops in the power leads 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.
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Chapter 4 Command Set The D3000/4000 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 D3000/4000 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. The Digital Input, Hex Output and Setup commands use hexadecimal representations of data. The data structures for these commands are detailed in the command descriptions. Write Protection Many of the commands listed in Table 4.1 are under the heading of ‘Write Protected Commands’. These commands are used to alter setup data in the module’s EEPROM.
Command Set 4-4 1) a normal response indicated by a ‘ * ‘ prompt 2) an error message indicated by a ‘ ? ‘ prompt 3) a communications time-out error When a module receives a valid command, it must interpret the command, perform the desired function, and the communicate the response back to the host. Each command has an associated delay time in which the module is busy calculating the response. If the host does not receive a response in an appropriate amount of time specified in Table 3.
Command Set 4-5 ample: Command: Response: $1RD *+00072.10 (no checksum) Command: Response: $1RDEB *+00072.10 (with checksum) Command: Response: $1RDAB ?1 BAD CHECKSUM (incorrect checksum) Command: Response: $1RDE ?1 SYNTAX ERROR (one extra character) Response Checksums If the long form ‘#‘ version of a command is transmitted to a module, a checksum will be appended to the end of the response. For example: Command: Response: $1RD *+00072.10 (short form) Command: Response: #1RD *1RD+00072.
Command Set 4-6 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 = 2A4 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. If checksums do not agree, a communications error has occurred.
Command Set 4-7 Table 4.1 D3000/4000 Command Set Command Definition D3000/4000 Commands ACK Acknowledge AO Analog Output DI Digital Input HX Hex Output RAO Read Analog Output RD Read Data RHI Read High Limit RID Read Identification RLO Read Low Limit RMS Read Manual Slope RMX Read Maximum RMN Read Minimum RS Read Setup RSU Read Setup WE Write Enable Typical Command Message Typical Response Message $1ACK $1AO+00020.
Command Set 4-8 Acknowledge (ACK) The ACKnowledge command is a hand-shaking command used in conjunction with the Analog Output (AO) command. It is used to confirm the data sent to a module. See the Analog Output (AO) command for examples of ACK usage. Command: Response: $1ACK * Command: Response: #1ACK *1ACK2A Analog Output (AO) The Analog Output (AO) command is the primary command used to control the analog output, whether it is current or voltage.
Command Set 4-9 are correct, it directs the module to go ahead and perform the AO by sending the ACK command. To complete the sequence: Command: Response: $1ACK * At this point the AO command will be performed by the module. If the host determines that the data is not correct, it may abort the handshaking sequence by sending any valid command to the module (except for the ACK command of course). Example: Command: Response: #1AO+00010.00 *1AO+00030.
Command Set 4-10 The data in the AO command is also checked against user-defined limits specified by the LO and HI commands. Exceeding the user-defined limits will generate a LIMIT ERROR. (See LO and HI commands). Any of the Manual Modes has priority over the AO command, and in some cases a MANUAL MODE error may be generated. See Manual Mode section for details. Digital Input (DI) The DI command reads the status of the digital inputs and the status of the analog output.
Command Set 4-11 Hex Output (HX) The HeX Output (HX) command controls the analog output by sending hexadecimal data directly to the Digital to Analog Converter (DAC). The D3000/4000 uses a 12-bit DAC with inputs ranging from $0000 (- full scale) to $0FFF (+ full scale) . The HX command uses this data to control the DAC: Command: Response: $1HX07FF * Command: Response: #1HX07FF *1HX07FFEE This command will set the DAC to half scale. The leading zero is included to allow for future enhancements.
Command Set 4-12 (AO) command. This is useful in applications where unrestricted outputs may cause damage or improper operation of other equipment or processes. The HI limit may be effectively disabled by setting it to it’s highest value: Command: Response: $1HI+99999.99 * The HI data may be read back with the Read HI (RHI) command. The HI command is write protected and must be preceded with a Write Enable (WE) command.
Command Set 4-13 LOw Limit (LO) The LOw Limit (LO) command sets a minimum limit to the analog output data. The data specified by the LO command is stored in nonvolatile memory and it is compared to the data specified by any subsequent Analog Output (AO) commands. If the AO data is less than the LO limit, the AO command is aborted and the module will generate a LIMIT ERROR message. Command: Response: $1LO+00004.00 * Command: Response: #1LO+00004.00 *1LO+00004.
Command Set 4-14 Manual Slope (MS) (D4000) The Manual Slope (MS) command sets the output slew rate for manual control using the UP* and DN* (down) input pins. The slope data is scaled in either mA/S or V/S: Command: Response: $1MS+00004.00 * Command: Response: #1MS+00004.00 *1MS+00004.00A8 These command examples set the manual slew rate to 4mA/S or 4V/S. The manual slope value only controls the output slew rate when using the manual UP* and DN* inputs.
Command Set 4-15 The MN and MX commands are covered thoroughly in chapter 10. The MN and MX values are saved in nonvolatile memory and may be read back with the Read MiNimum (RMN) and Read MaXimum (RMX) commands. The MN and MX commands are write-protected. Read Analog Data (RAD) (D4000) All D4000 modules contain an Analog-to-Digital Converter (ADC) which may be used to directly monitor the analog output signal. The ADC data is obtained with the Read Analog Data (RAD) command.
Command Set 4-16 Command: Response: #1RAO *1RAO+00017.50F3 Read Data (RD) The Read Data (RD) command reads back the digital data being sent to the DAC at the time the RD command is performed. It is used to obtain the status of the output signal at any time. The data obtained is scaled in the same units as used with the Analog Output (AO) command. Command: Response: $1RD *+00010.00 Command: Response: #1RD *1RD+00010.
Command Set 4-17 Command: Response: #1RHI *1RHI+00020.00E9 Read IDentification (RID) The Read IDentification (RID) command reads out the user data stored by the IDentification (ID) command. The ID and RID commands are included as a convenience to the user to store information in the D3000’s nonvolatile memory.
Command Set 4-18 Command: Response: #1RMS *1RMS+00004.00FA Read MaXimum (RMX) The Read MaXimum (RMX) command reads out the scaling data corresponding to + full scale at the analog output. The MaXimum data may be changed by using the MX command (D4000 only). Command: Response: $1RMX *+00020.00 Command: Response: #1RMX *1RMX+00020.00FD Read MiNimum (RMN) The Read MiNimum (RMN) command reads out the scaling data corresponding to - full scale at the analog output.
Command Set 4-19 The response contains the module’s channel address, baud rate and other parameters. Refer to the setup command (SU), and Chapter 5 for a list of parameters in the setup information. When reading the setup with a checksum, be sure not to confuse the checksum with the setup information. Command: Response: $1RSU *310701C0 Command: Response: #1RSU *1RSU310701C0F4 The Read Setup (RS) command performs the same function, and is included to be compatible with the D1000/2000 series.
Command Set 4-20 Response: *+00005.00 Command: Response: #1RSV *1RSV+00005.0004 Read Watchdog Timer (RWT) (D4000) The Read Watchdog Timer (RWT) command reads the time interval necessary to activate the watchdog timer. The data is scaled in minutes. Command: Response: $1RWT *+00010.00 (10 minutes) Command: Response: #1RWT *1RWT+00010.0002 (10 minutes) In each of the two example commands, the response data indicates that the watchdog timer period is 10 minutes.
Command Set 4-21 The SetUp command is used to modify the user-specified parameters contained in the EEPROM to tailor the module to your application. Since the SetUp command is so important to the proper operation of a module, a whole section of this manual has been devoted to its description. See Chapter 5.
Command Set 4-22 automatically performs an internal Analog Output (AO) command with the stored data. If the AO command would have resulted in an error (LIMIT ERROR, MANUAL MODE) the start-up command is aborted and the D4000 will start up at - Full Scale. The scaling of the start-up data is determined by the input scaling range fixed by the MiNimum (MN) and MaXimum (MX) limits. The Starting Value is the ‘safe’ output value used when the watchdog timer times out. See D4000 section.
Command Set 4-23 The TRX and TRN commands are used on D4000 modules to trim the Analog-to-Digital Converter (ADC) which provides the analog readback of the output signal. Refer to the Calibration section. Command: Response: $1TRN * Command: Response: #1TRN *1TRN4F Watchdog Timer (WT) (D4000) The Watchdog Timer (WT) command stores a data value in EEPROM specifying the time-out value of the watchdog timer. The time data is scaled in minutes: Command: Response: $1WT+00010.
Command Set 4-24 Response: * Command: Response: #1WE *1WEF7 If a module is write enabled and the execution of a command results in an error message other than WRITE PROTECTED, the module will remain write enabled until a command is successfully completed resulting in an ‘*’ prompt. This allows the user to correct the command error without having to execute another WE command.
Command Set 4-25 NULL ($00), CR ($0D), $ ($24), and # ($23). The ADDRESS ERROR will occur when an attempt is made to load an illegal address into a module with the SetUp (SU) command. An attempt to load an address greater than $7F will also produce an error. BAD CHECKSUM This error is caused by an incorrect checksum included in the command string. The module recognizes any two hex characters appended to a command string as a checksum.
Command Set 4-26 module parity. In this situation, the easiest solution may be to change the parity in the host to obtain communication. At this point the parity in the module may be changed to the desired value with the SetUp (SU) command. The parity may be changed or turned off by using Default Mode. SYNTAX ERROR A SYNTAX ERROR will result if the structure of the command is not correct. This is caused by having too few or too many characters, signs or decimal points missing or in the wrong place. Table 4.
Chapter 5 Setup Information/SetUp Command The 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 Information and 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: $1SU31070180. 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.
Setup Information and 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 four ASCII codes that are illegal for use as an address. These codes are $00, $0D, $24, $23 which are ASCII codes for the characters NUL, CR, $, and #.
Setup Information and 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 modules are terminated with a carriage return (ASCII $0D). Most terminals will generate a automatic linefeed when a carriage return is detected.
Setup Information and SetUp Command 5-5 accidently lost. This is very important when changing the baud rate of an RS232C string. Let’s run through an example of changing the baud rate. Assume our sample module contains the setup data value of ‘31070180’. 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 Information and SetUp Command 5-6 If the module does not respond to the new baud rate, most likely the setup data is incorrect. Try various baud rates from the host until the module 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. Bits 3 and 4 These two bits of byte 2 are not used and should be set to ‘0’. Table 5.
Setup Information and SetUp Command 5-7 Byte 3 This byte contains the setup information for additional communications options. The default value for this byte is ‘01’. Continuous Input (D4000) Bit 5 enables the continuous input option available on D4000 units and it is normally set to ‘0’. Setting Bit 5 to ‘1’ enables the continuous input. Refer to the D4000 section for more information on the continuous input option.
Setup Information and SetUp Command 5-8 Table 5.3 Byte 3 Options. BYTE 3 FUNCTION DATA BIT 7 6 5 4 0 0 0 1 0 1 NOT USED CONTINUOUS DISABLED CONTINUOUS ENABLED LIMITS ENABLED LIMITS DISABLED NOT USED NO ECHO ECHO NO DELAYS 2 BYTE TIME DELAYS 4 BYTE TIME DELAYS 6 BYTE TIME DELAYS 3 2 1 0 0 0 1 1 0 1 0 1 0 0 1 Byte 4 This setup byte specifies the number of displayed digits and the Manual Mode configuration.
Setup Information and SetUp Command 5-9 Manual Mode Disable Bit 2 is normally set to ‘0’ which allows the Manual Mode inputs to affect the analog output. Setting bit 2 to ‘1’ disables the Manual Modes. Manual Mode Select Bits 0 and 1 allow the user to select among four different Manual Modes. Manual Modes allow the analog output to be controlled by the UP* and DN* pins on the module connector. Details on Manual Modes are given in the Manual Mode section. Table 5.
Setup Information and SetUp Command 5-10 setup with the Read Setup command: Command: Response: $1RS *310701C0 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 and Manual Mode MANUAL MODES/DIGITAL INPUTS Each D3000/4000 module has three digital input connections designated as DI0/DN*, DI1 /UP*, and DI2. These inputs have a dual function; they may be used as control inputs which influence the analog output or they may be used as general-purpose digital inputs. The function of the input pins is programmable with the SetUp (SU) command.
Digital I/O Functions and Manual Mode 6-2 MANUAL MODES The D3000/4000 modules may be configured to use the digital inputs to control the analog output. These functions are called Manual Modes. Four different Manual Modes may be specified: Up/Down Controller Input Limit Switch NO Limit Switch NC These modes are selected by Bits 0 and 1 of Byte 4 in the Setup data. (See Setup section). Also, the Manual Mode Disable bit (Bit 2, Byte 4) must be cleared to enable Manual Modes.
Digital I/O Functions and Manual Mode 6-3 Figure 6.2 Manual Up/Down Control. The slope rate on D3000 modules is fixed and cannot be changed. The manual slope on D3000 units is scaled so that a full-scale output change requires 5 seconds to complete. The manual slope rate on D4000 units may be programmed to any desired value with the Manual Slope (MS) command. The Manual Modes have priority over host-generated output commands.
Digital I/O Functions and Manual Mode 6-4 Figure 6.3 Manual Up/Down Control With Host Lock-Out. CONTROLLER INPUT This Manual Mode is a variation of the manual up/down control specifically setup for operation with ON-OFF controllers. With this mode, a D3000/4000 unit may be used to add an analog control output to an ON-OFF or timeproportional controller.
Digital I/O Functions and Manual Mode 6-5 LIMIT SWITCHES Two of the Manual Modes allow the use of limit switches or other external digital signals to limit the analog output that may be obtained with the Analog Output (AO) command. The limit switch mode may be programmed to accommodate either normally-open (NO) switches or normally-closed (NC) switches. See the Setup section for mode selection details. Figure 6.4 shows a typical module with normally-open limit switches.
Digital I/O Functions and Manual Mode 6-6 Figure 6.5 Using Limit Switches To Stop An Analog Output Ramp. On D4000 units with controlled output ramps, the limit switches will stop the output even after a successful AO command. Figure 6.5 illustrates this action. In this example a D4181 voltage-output module is programmed with an output slope of 1V/S. Assume that the output voltage value is initially 0V. The command: $1AO+10000.00 will ramp the output to +10V.
Chapter 7 Power Supply D3000/4000 modules may be powered with an unregulated +10 to +30Vdc supply. 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. All power supply specifications are referred to the module connector; the effects of line voltage drops must be considered when the module is powered remotely.
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Chapter 8 Troubleshooting Symptom: RS-232 Module is not responding to commands. RS-485 Module is not responding to commands. 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. Using a voltmeter, measure the power supply voltage at the +Vs and GND terminals to verify the power supply voltage is between +10 and +30Vdc. 2.
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 D3000/4000 units feature state-of-the art digital trimming techniques to eliminate the need for calibration pots or other hardware trims. Calibration is performed with trim commands through the communications port. The onboard microprocessor is used to calculate calibration constants which are then stored in the nonvolatile EEPROM. Field calibration of the units may be performed without the need to physically access the device.
Calibration 9-2 Calibration Procedure-Voltage units 1) Connect voltmeter to analog output 2) Set the output to -full scale with Analog Output (AO) command. 3) Measure the output voltage. 4) Report the actual output value to the module with the Trim MiNimum (TMN) command. The module will adjust the output to a new value. 5) Check the output value with the meter. If the output is not within 1LSB, repeat step 4. 6) Set the output to + full scale with the Analog Output (AO) command.
Calibration 9-3 The measured output is +10.123V. Report the measured output to the module with the Trim Maximum (TMX) command: Command: Response: $1WE * Command: Response: $1TMX+10123.00 * The output now measures +10.005V, which is still not within specification. Repeat the TMX command with the new value: Command: Response: $1WE * Command: Response: $1TMX+10005.00 * The output now measures 9.999V, which is within 1LSB (2.5mV).
Calibration 9-4 be easier to re-scale the D4000 to standard voltage and current ranges that may be compared directly with measured output values. Calibration is then performed with the same procedure as described above. After calibration, the module may be re-scaled back to any desired engineering units with the MN and MX commands. Analog Readback Calibration The analog-to-digital converter (ADC) used for readback is trimmed independently of the DAC.
Calibration 9-5 D4000 Calibration Addendum Due to a microprocessor 'bug', early production D4000 units will not execute the TRN command if the -full scale value is negative. An attempt to execute the TRN command will result in a VALUE ERROR. However, the ADC on these units may be trimmed by using the following procedure: Read the -full scale value by using the Read MiNimum (RMN) command: Command: Response: $1RMN *-10000.00 (typical data) Record the -full scale data for later use.
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Chapter 10 D4000 Features D4000 Features The D4000 series of computer-to-analog output modules contain many intelligent enhancements not found in the D3000. The D4000 accepts all of the D3000 commands and contains several additional commands which take full advantage of the computational power of the on-board microprocessor.
D4000 Features 10-2 nearest value that can be represented by the 12-bit D-to-A converter and a new output is obtained. In this manner the DAC is smoothly stepped until the final output value is reached as specified by the Analog Output (AO) command. The incremental steps obtainable from the 12-bit converter and the 1ms conversion rate combine to make the output change appear to be a linear ramp.
D4000 Features 10-3 command is used twice a minute to control acceleration and deceleration, the 10,000 cycle write limit of the EEPROM will be exceeded within 4 days of operation. To overcome this limitation, the Slope (SL) command may be used to dynamically change the slew rate. Since the SL command writes only to RAM, the slope data may be changed an unlimited number of times. The Read Present Slope (RPS) command reads the slope data contained in RAM.
D4000 Features 10-4 Manual Slopes The D4000 allows the user to specify the output slew rate when the output is controlled by the manual UP/DN inputs. The Manual Slope (MS) command is used to write the rate data in EEPROM. The manual slope rate is totally independent of the slew rates used with the computer controlled output (AO command). The manual slope rate may be read back with the Read Manual Slope (RMS) command.
D4000 Features 10-5 scale. Example: A D4181 voltage output module is used to supply the control signal to a motor speed controller. The full scale range of the D4181 is 0 to +10V. With this voltage input the motor speed varies from 100 to 3000 RPM. To command the motor to turn at a specified RPM requires some computation to obtain the correct command data. For instance, to command the motor to run at 1500 RPM requires the command: Command: Response: $1AO+04666.
D4000 Features 10-6 input value of 100%: Command: Response: $1MX+00100.00 * The module is now scaled in percentage of valve opening. To set the valve to 50% opening: Command: Response: $1AO+00050.00 * In this case the D4000 module produces an output of 12mA, opening the valve halfway. If a D4000 module has been rescaled, the readback data obtained from the Read Data (RD) and Read Analog Data (RAD) commands are automatically rescaled to the new units.
D4000 Features 10-7 command. The SV and RSV commands are detailed in the command section of chapter 4. WATCHDOG TIMER D4000 units contain a programmable software timer to provide an orderly shutdown of the output signal in the event of host computer or communications failure. The timer is preset using the Watchdog Timer (WT) command to specify a timer interval in minutes. The timer is continually incremented in software.
D4000 Features 10-8 provides readback data to the microprocessor. The analog data may be read back with the Read Analog Data (RAD) command. The RAD data provides true analog readback scaled in the same units as provided with the RD command. The ADC is not intended to be a highly accurate measurement of the output signal. Typical accuracy is about 1% of full scale (see specifications).
D4000 Features 10-9 D4000 units may be configured to operate in a special mode called Continuous Input Mode. This mode allows the D4000 to be slaved directly to a D1000 or D2000 sensor interface unit. Figure 10.1 shows a typical application. In this example, a D1251C sensor module is used to convert a 0-20mA process signal to ASCII data. The D1251C is operated in continuous output mode to produce data without a host.
D4000 Features 10-10 couple. This is accomplished by rescaling the D4251: Command: Response: $1MN+00100.00 * Command: Response: $1MX+00300.00 * Continuous Input Setup The Continuous Input Mode may be specified by setting bit 5,byte 3 of the setup data (see setup chapter). In addition, the DI2 terminal pin must be grounded before the module will accept continuous input commands. The DI2 connection provides an external means of controlling the continuous input option.
Appendix A ASCII TABLE Table of ASCII characters (A) and their equivalent values in Decimal (D), Hexadecimal (Hex), and Binary. Claret (^) represents Control function.
ASCII TABLE A-2 A # $ % & ‘ ( ) * + , .
ASCII TABLE A-3 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 0101101
ASCII TABLE A-4 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 Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.
Appendix B D3000/4000 Specifications Specifications (@ +25°C and nominal power supply voltage). Analog Output • Single channel analog output. Voltage: 0-1V, ±1V, 0-5V, ±5V, 0-10V, ±10V. Current: 0-20mA, 4-20mA. • Output isolation to 500V rms. • 12-bit output resolution. • Accuracy (Integral & Differential Nonlinearity): 0.1%FSR (max). • Zero drift: ±30µV/°C (Voltage Output). ±1.0µA/°C (Current Output). • Span tempco: ±50ppm/°C max. • 1000 conversions per second. • Settling Time to 0.
D3000/4000 Specifications B-2 Communications • RS-232C, RS-485. • Up to 124 multidrop modules per host communications port. • User selectable channel address. • Selectable baud rates: 300, 600, 1200, 2400, 4800, 9600,19200, 38400. • ASCII format command/response protocol. • Can be used with “dumb” terminal. • Parity: odd, even, none. • All communications setups (address, baud rate, parity) stored in nonvolatile memory using EEPROM. • Checksum can be added to any command or response.
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