Omega A2400 manual Command 01WE Response *01WE27, Error Messages, Address Error, BAD Checksum

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Command Set 4-17

Command: }01WE

Response: *01WE27

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.

ERROR MESSAGES

All modules feature extensive error checking on input commands to avoid erroneous operation. Any errors detected will result in an error message an 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 seven error messages, and each error message begins with a different character. Host computer software can identify an error by the first character; it is not necessary to read the whole string.

ADDRESS ERROR

There are six ASCII values that are illegal for use as a module address: NULL ($00), CR ($0D), $ ($24) , # ($23), { (123) and } (124). 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 value greater that $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. Usually a BAD CHECKSUM error is due to noise or interference on the communications lines. Often, repeating the command solves the problem. If the error persists, either the checksum value was calculated incorrectly or there is a problem with the communica- tions channel. More reliable transmissions might be obtained by using a lower baud rate.

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Contents User’sGuide Servicing Europe Servicing North AmericaFor immediate technical or application assistance BOX Revised 4/17/95Omega Engineering ONE Omega Drive 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 StructureMiscellaneous Protocol Notes Data StructureWrite Protection Response StructureCommand Checksum Long Form Responses$1WEF ?1 Syntax Error?1 BAD Checksum A2400 User Commands A2400 Command Set RT3Command $1DO01 Response Command #1DO01 Response *1DO014F Command DescriptionsCommand 01CC Response Response *01CC11 Digital Output do 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 $1RIDTank Farm 1RID Tank Farm 11F$1RSP $1RSU#1RSU #1RSPResponse *+00100.00 Read Time Delay 1 RT1Response *1RT1+00100.00DC Read Time Delay 2 RT2 Page Page Short Prompt SP Address Error Command 01WE Response *01WE27Error Messages BAD ChecksumSyntax Error Command ErrorParity 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 Byte 2 Linefeed, Parity and Baud Rate Command $1RR ResponseBit 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 01CC Response Command 01OC ResponseCommand $1RD Response +00100.00 Typical $2RD +00123.45 Command 02OC ResponseStructured Addressing Extended Address SyntaxImplied OC Command OC and CC Command FormatsImplied CC 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