Omega A2400 manual Command 01OC Response, Command $1RD Response +00100.00 Typical $2RD +00123.45

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Extended Addressing 9-3

When the system is initially powered up, the A2400’s are set to the Close Channel condition. This means that no data received by the radio modems will pass to the RS-485 bus at either site. In order to communicate to the modules, one of the A2400’s must be set to the Open Channel condition:

Command: {01OC

Response: *

This command orders the A2400 address ‘01’ to open the ‘data gate’ between the radio modem and the two-module string on the RS-485 bus. Now the host computer may communicate to the modules in a normal fashion:

Command:

$1RD

 

Response:

*+00100.00

(typical)

Command:

$2RD

 

Response:

*+00123.45

(typical)

Note that A2400 address ‘02’ is still in a Close Channel state. No data received by this A2400 will be allowed to pass to the RS-485 bus. Therefore there is no conflict between the two module strings containing identical addresses. Only one A2400 is allowed to be in an Open Channel state at any time.

To access the module string located at A2400 address ‘02’, first close the channel at A2400 #01:

Command: {01CC

Response: *

Now open the ‘data gate’ at A2400 #02:

Command: {02OC

Response: *

Any commands from the host are now directed through A2400 #02:

Command: $1RD

Response: *+00000.00

Command: $2RD

Response: *00005.00

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Contents User’sGuide For immediate technical or application assistance Servicing North AmericaServicing Europe STAMFORD, CT Phone 1-800-DAS-IEEE Revised 4/17/95Omega Engineering ONE Omega Drive BOXTable of Contents Introduction Chapter Getting StartedLeased Lines System Overview+99999.99 $1RDDefault Mode Page Chapter Functional Description Block DiagramFunctional Description Pinout A2400 Operation RS-485 TerminationCharacter Filter Page Programmable Delay Times Page Chapter Communications Command $1RD Response *+99999.99DO, OC, CC, RD, REA, RID, RLP, RS, RSP, RSU Communication DATA+ RS-485 Multidrop SystemPage Command Structure Chapter A2400 Command SetResponse Structure Data StructureWrite Protection Miscellaneous Protocol NotesLong Form Responses Command Checksum?1 BAD Checksum ?1 Syntax Error$1WEF A2400 User Commands RT3 A2400 Command SetClosed Channel CC Extended Command DescriptionsCommand 01CC Response Response *01CC11 Digital Output do Command $1DO01 Response Command #1DO01 Response *1DO014FExtended Address EA Command $1DO00 Response Command #1DO00 Response *1DO004E#1ID Tank Farm $1ID Tank Farm1ID Tank Farm 1CD Open Channel OC Extended Command 01OC Response Response *01OCEDRead Data RD 1RID Tank Farm 11F $1RIDTank Farm #1RID#1RSP $1RSU#1RSU $1RSPResponse *1RT1+00100.00DC Read Time Delay 2 RT2 Read Time Delay 1 RT1Response *+00100.00 Page Page Short Prompt SP BAD Checksum Command 01WE Response *01WE27Error Messages Address ErrorValue Error Command ErrorParity Error Syntax ErrorCommand Syntax Chapter Setup Information/SetUp Command$1SUbyte 1byte 2byte 3byte Byte HEX Ascii Byte 1 Ascii Printable CharactersBaud Rate ParityCommand $1WE Response Command $1SU31020000 Command $1RS Response *31070000Command $1RS Response *31020102 Command $1WE Baud Command $1RR ResponseBit Byte 2 Linefeed, Parity and Baud RateNormal addressing Chapter Delay Time Programming Delay Time Programming Page Command $1RT1 Response *+00100.00 Command $1T3+00050.00 Set T3 to 50 ms ResponseChapter Power Supply Symptom RS-232 Module is not responding to commands Chapter TroubleshootingSymptom RS-485 Module is not responding to commands Open/Close Channel Commands Command 01WE ResponseChapter Extended Addressing Typical system overview Command 02OC Response Command 01OC ResponseCommand $1RD Response +00100.00 Typical $2RD +00123.45 Command 01CC ResponseExtended Address Syntax Structured AddressingCommand Response OC and CC Command FormatsImplied CC Command Implied OC CommandCommand 01$1RD Response *+00100.00 Command Response *01OC1D Single Command Module AddressExplicit Open and Close Channel Commands Command 02OC Response 02OC1E ‘1E’ is the checksum Command 01CC Response 01CC11 ‘11’ is the checksumTransparent Mode Functions Chapter Transparent ModeA2400 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