Omega A2400 manual Default Mode

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Getting Started 1-4

This message is terminated with a carriage return. If the response message cannot be obtained, re-check all the wiring, making sure that the proper power is on the A2400 connector and that the DEFAULT* line is shorted to the GND pin. The terminal must be set to 300 baud.

If, after several attempts, the response message does not appear, refer to Chapter 8 Troubleshooting in this manual.

If you have an IBM PC or compatible computer, running the S1000 setup software will ease the task of setting up the A2400 for your application.

After establishing communications with the A2400, read the manual and feel free to experiment with the various commands and setups available. If communications is lost due to an improper setup, returning back to the hook- up of Figure 1.2 will restore communications to the A2400.

Default Mode

The A2400 contains an EEPROM (Electrically Erasable Programmable Read Only Memory) to store setup information. The EEPROM replaces the usual array of switches 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.

The EEPROM provides tremendous system flexibility since all of the setup parameters may be configured remotely through the communications port without having to physically change switch settings. There is one 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 A2400 what the baud rate, address, parity and other settings are. It is difficult to establish communications with a A2400 whose address and baud rate are unknown. To overcome this, the A2400 has a pin labeled DEFAULT*. By connecting this pin to ground (GND) the A2400 is forced to a known communications setup called Default Mode.

The Default Mode setup is: 300 baud, no parity, any address is recognized.

Grounding the DEFAULT* pin does not change any of the setups stored in EEPROM. The setup may be read back with the Read Setup (RS) command to determine the communications parameters stored in the A2400.

An A2400 in Default Mode will respond to any address except the six illegal

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Contents User’sGuide Servicing Europe Servicing North AmericaFor immediate technical or application assistance Revised 4/17/95 Omega Engineering ONE Omega DriveBOX STAMFORD, CT Phone 1-800-DAS-IEEETable of Contents Chapter Getting Started IntroductionSystem Overview Leased Lines$1RD +99999.99Default Mode Page Block Diagram Chapter Functional DescriptionFunctional Description Pinout Character Filter RS-485 TerminationA2400 Operation Page Programmable Delay Times Page Command $1RD Response *+99999.99 Chapter CommunicationsDO, OC, CC, RD, REA, RID, RLP, RS, RSP, RSU Communication RS-485 Multidrop System DATA+Page Chapter A2400 Command Set Command StructureData Structure Write ProtectionMiscellaneous Protocol Notes Response StructureCommand Checksum Long Form Responses$1WEF ?1 Syntax Error?1 BAD Checksum A2400 User Commands A2400 Command Set RT3Command Descriptions Command 01CC Response Response *01CC11 Digital Output doCommand $1DO01 Response Command #1DO01 Response *1DO014F Closed Channel CC ExtendedCommand $1DO00 Response Command #1DO00 Response *1DO004E Extended Address EA1ID Tank Farm 1CD $1ID Tank Farm#1ID Tank Farm Read Data RD Command 01OC Response Response *01OCEDOpen Channel OC Extended $1RID Tank Farm#1RID 1RID Tank Farm 11F$1RSU #1RSU$1RSP #1RSPResponse *+00100.00 Read Time Delay 1 RT1Response *1RT1+00100.00DC Read Time Delay 2 RT2 Page Page Short Prompt SP Command 01WE Response *01WE27 Error MessagesAddress Error BAD ChecksumCommand Error Parity ErrorSyntax Error Value Error$1SUbyte 1byte 2byte 3byte Chapter Setup Information/SetUp CommandCommand Syntax Byte Byte 1 Ascii Printable Characters HEX AsciiParity Baud RateCommand $1RS Response *31020102 Command $1WE Command $1RS Response *31070000Command $1WE Response Command $1SU31020000 Command $1RR Response BitByte 2 Linefeed, Parity and Baud Rate BaudNormal addressing Chapter Delay Time Programming Delay Time Programming Page Command $1T3+00050.00 Set T3 to 50 ms Response Command $1RT1 Response *+00100.00Chapter Power Supply Symptom RS-485 Module is not responding to commands Chapter TroubleshootingSymptom RS-232 Module is not responding to commands Chapter Extended Addressing Command 01WE ResponseOpen/Close Channel Commands Typical system overview Command 01OC Response Command $1RD Response +00100.00 Typical $2RD +00123.45Command 01CC Response Command 02OC ResponseStructured Addressing Extended Address SyntaxOC and CC Command Formats Implied CC CommandImplied OC Command Command ResponseExplicit Open and Close Channel Commands Command Response *01OC1D Single Command Module AddressCommand 01$1RD Response *+00100.00 Command 01CC Response 01CC11 ‘11’ is the checksum Command 02OC Response 02OC1E ‘1E’ is the checksumChapter Transparent Mode Transparent Mode FunctionsA2400 interfacing a PLC to a leased-line modem A2400 networking several RS-232 devices to a host computer A2400 interfacing a laboratory instrument with modules Transparent Mode Adding secondary control using A2400 modules Transparent Mode WARRANTY/DISCLAIMER Shop online at omega.com