Omega A2400 manual Parity, Baud Rate

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SetUp Command 5-4

Byte 2

Byte 2 is used to configure some of the characteristics of the communica- tions 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. However, for terminals that do not have this capability, the modules can generate the linefeed if desired. By setting bit 7 to ‘1’ the module will send a linefeed (ASCII $0A) before and after each response. If bit 7 is cleared (0), no linefeeds are transmitted.

When using the ‘#’ command prompt, the linefeed characters are not included in the checksum calculation.

Parity

Bits 5 and 6 select the parity to be used by the module. Bit 5 turns the parity on and off. If bit 5 is ‘0’, the parity of the command string is ignored and the parity bit of characters transmitted by the module is set to ‘0’.

If bit 5 is ‘1’, the parity of command strings is checked and the parity of characters output by the module is calculated as specified by bit 6.

If bit 6 is ‘0’, parity is even; if bit 6 is ‘1’, parity is odd.

If a parity error is detected by the module, it will respond with a PARITY ERROR message. This is usually caused by noise on the communications line.

If parity setup values are changed with the SU command, the response to the SU command will be transmitted with the old parity setup. The new parity setup becomes effective immediately after the response message from the SU command.

Baud Rate

Bits 0-3 specify the communications baud rate. The baud rate can be selected from ten values between 300 and 115200 baud. Refer to Table 5.2 for the desired code.

The baud rate selection is the only setup data that is not implemented directly after an SU command. In order for the baud rate to be actually

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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