Serial Communications Protocol - Cooper Industries

1 Serial Communications ProtocolData 2179 Revision 4 For Use WithCooper Power Systems Apparatus Controls: Form 6 Recloser Control Form 5 Recloser Control Form 4C Recloser Control CL-6A Regulator Control CL-5C Regulator Control CL-5A Regulator Control CL-4C Regulator ControlControlsSerial Communications ProtocolR280-90-12 Reference InformationAugust 2004 Supersedes 6/00 Printed in USA1 TABLE OF Functions .. Internal Control, Function 20 .. RTU Configuration, Function Number 38 Appendix A Example Transactions .. 402 The Protocol specified in this document is a subset of the "Remote Terminal Unit Protocol "developed by Pacific Gas and Electric Company, San Francisco, california . This Protocol subsethas been developed jointly by Cooper Power Systems and Pacific Gas and Electric Company. Theprotocol is incorporated in Cooper Power Systems' products for general use by Cooper PowerSystems customers with the consent of Pacific Gas and Electric the context of this specification, "RTU" means the Cooper Power Systems equipmentincorporating this Protocol , and "Master" means the device interfaced to and controlling the CooperPower Systems equipment via this BASIC MASTER MESSAGE FORMATThe following is a description of the physical format for the transmission of databetween the MASTER and the REMOTE TERMINAL UNIT (RTU).

2 2 Characters 1 Character 1 Character 2 Characters2 CharactersMaster / RTUA ddressFunctionCodeCommandNumber ofCharactersData Character Format ASYNC / 8 DATA Bits / 1 Stop Bit / No ParityNOTE: Two byte words are sent low byte first, including ADDRESS and NUMBER OF CHARs, DATA and RTU Address Two characters that specify the address of the polling MASTERand the desired RTU. There are 5 bits for the MASTER address (0-1F HEX [0to 31 decimal]) and 11 bits for the RTU address (000-7FE HEX [0-2046 DECIMAL]). An address of 7FF HEX is used for a broadcast FOR ADDRESS CHARACTERS (from master)Character 2 Character 17654321076543210M04 M03 M02 M01 M00 R10 R09 R08 R07 R06 R05 R04 R03 R02 R01 R00 Master AddressRemote Function Code A one character code that defines the function to be OperationBITS 0-5 - Function that is to be performedBITS 6-7 - Reserved for other system functions4 TABLE 1-1 List of Function CodesFUNCTIONCODEOPERATION00 BASIC SCAN OPERATION All data of type(s)

3 Specified in the COMMAND character will be returned in for FLOATING POINT TIME-TAGGED INFORMATION0 ASCAN BY TABLE- Return data specified in the table named in the CONTROL Perform control operation defined in theCOMMAND character and parameters20 RTU INTERNAL CONTROL AND CONFIGURATION Configure orcontrol as specified in the COMMAND character and parameters25 RETURN RTU CONFIGURATION The RTU will respond with internalinformation as specified by the ** CANNOT BE USED** Master Message Command Character A one-character message containing thespecific operation within the function that the RTU should perform. Themeaning of these command bits will change for specific functions and will bedetailed when the function is discussed in later Number of Characters 2 characters that specify the number of characters in theDATA Field. If it is 00, there are no data characters.

4 The maximum number ofcharacters in the data field is 128 for a normal SCADA Data Field A variable length field containing operation information in additionto the function and command bytes ( , sequence numbers, parameters,configuration, etc.) CRC16 A 2 character CRC (Cyclical Redundancy Check) of all of thecharacters in the entire X16+X15+X2+1 is the polynomial (initialized as 0000 for table look-up) BASIC REMOTE MESSAGE FORMAT2 Chars 1 Char 1 Char 1 Char 2 Chars Data Field 2 CharsMaster / RTUA ddressFunctionCodeStatus PortStatusNo Character Format ASYNC / 8 DATA Bits / 1 Stop Bit / No ParityNOTE: Two byte words are sent low byte first, including ADDRESS NUMBER OF CHARACTERS, DATA and RTU Address Two characters that specify the addresses of the pollingMASTER and the responding FOR ADDRESS CHARACTERS (from remote)Character 2 Character 17654321076543210M04 M03 M02 M01 M00 R10 R09 R08 R07 R06 R05 R04 R03 R02 R01 R00 Master AddressRemote Function Code A one function code that defines the purpose of the message(see table 1-1, Function Codes).

5 The RTU generally echoes the functioncode sent by the MASTER, except when the RTU cannot perform therequested function due to an error, time-out, bad parameters, or some othercondition that is not logical to the NOPF unctional Operation6 DESCRIPTIONBit 00-05 FUNCTION normally an echo of the master 06 RESULT NOP NO OPERATION. The RTU returns a NOPwhen it has reached time-out on a selected function; aninvalid function or parameter; or other format error.** IF PARITY, FRAMING OR CRC ERROS ARE DETECTED THE RTU WILLIGNORE THE MESSAGE AND NOT RESPOND **Bit 07 RESULT RST RESET The RTU returns a RST when itreceives an out of sequence command while there is a selectfunction active or an Operate or Execute command when noSelect is Remote to Master Status Byte This character contains flags that informthe MASTER of current RTU STATUS76543210 Bit 7: 1= Remote needs to be configured by MASTER.

6 This flag is set with power on or RTU manual 6: 0 = Always 0 - RESERVED -Bit 5: 0 = Always 0 - RESERVED -Bit 4: 0 = Always 0 - RESERVED -Bit 3: 1 = Error - Read RTU error file to determine problemBit 2: 1 = Acknowledge broadcast message set to inform the MASTER that the RTU has received an address of 7FF 1: 0 = Always 0- RESERVED-Bit 0: 0 = Always Remote Communications Port Status Byte This character informs theMASTER of the status of all 4 RTU Communications are two Bit s for each port. If a port is not equipped, its status will bea Binary 0-1: COM Port 1 statusBit 2-3: COM Port 2 status (if equipped)Bit 4-5: COM Port 3 status (if equipped)Bit 6-7: COM Port 4 status (if equipped)MEANING OF 2-BIT PORT STATUS: 00 = COMM PORT OK 01 = No data received for 1 minute or more 10 = PARITY or CRC error 11 = Loss of Number of Characters - 2 characters that specify the number of characters inthe DATA FIELD.

7 If it is 00, there are no data characters. The maximumnumber of characters in the DATA FIELD is 511 for normal Data Field - A variable length field containing information requested by theMASTER ( , STATUS and ANALOG quantities). CRC16 - A 2 character CRC (CYCLICAL REDUNDANCY CHECK) of allof the characters in the entire message. X16+X15+X2+1 is the polynomial. (INITIALIZE AS 0000 FOR TABLE LOOK-UP) ASYNCHRONOUS DATA TRANSMISSION FORMAT Each character is sent in an asynchronous manner using one (1) start bit, eight (8)data bits, one (1) stop bit and no parity. The character is transmitted/received loworder bit (0) first. In this document bit 0 is on the right end of any byte and theformats are drawn so the order of transmission of characters is from left to SYNCHRONOUS DATA FORMAT- TO BE DETERMINED WHEN RTU CONFIGURATION The following paragraphs contain information on RTU SEQUENCE NUMBERSThis Protocol provides transparency to the RTU hardware through the use of sets ofSEQUENCE NUMBERS and allows the MASTER STATION to communicate withRTUs without regard to hardware on sequence number assignments for each device implementing this protocolare contained in separate specifications for each particular shown in TABLE 2-1, there is one set of sequence numbers for each subsystemin the 2-1 SEQUENCE NUMBERS FOR RTU SUBSYSTEMS INPUT SUBSYSTEM: status, analog and pulse accumulator.

8 Sequence #00 through FF (see for description). - 00-1F ARE SEQ #s FOR 2-BIT STATUS CHANGES - 30-3F ARE SEQ #s FOR SIMPLE STATUS - 40-5F ARE SEQ #s FOR PULSE ACCUMULATORS - 80-FF ARE SEQ #s FOR ANALOG INPUTS CONTROL OUTPUT SUBSYSTEM Sequence #00 through FF (see for description). SPECIAL CALCULATIONS SUBSYSTEM Sequence #00 through 7F (see for description). FORMAT FOR DATA TYPES - RTU SCAN ABBREVIATIONS9 The following table contains definitions of the abbreviations used in messageformats. TABLE 2-2 FORMAT ABBREVIATIONSRA REMOTE ADDRESS - two FUNCTION CODE - defines required COMMAND BYTE - defines specific functionalSSTATUS BYTE current RTU PORT STATUS BYTE contains 2 bits for each of 4 possible NUMBER OF CHARACTERS included in all MASTER and RTU messages toindicate the number of characters in the data CYCLICAL REDUNDANCY CHECK Two characters that hold the result ofcharacter by character CRC calculation of all characters in the Bit Numbering Convention MSB LSB BIT 15 BIT Format for 2-bit status change - 2 bits per status point.

9 Consisting ofinstantaneous and a change bit to indicate multiple changes of statebetween scans - sent in 16 bit Format for Simple Status Points - instantaneous state of status inputs when scanned (sent in 16 bit groups).Low Order 8 BitsHigh Order 8 BitsS07 S06 S05 S04 S03 S02 S01 S00 S15 S14 S13 S12 S11 S10 S09 S08 Character 1 Character Format for sending 16 bit Analog Values - returned in scan response if BIT 03is set in the MASTER command character on a basic 1 scan request. Theformat in two's complement binary Order 8 BitsHigh Order 8 BitsA07 A06 A05 A04 A03 A02 A01 A00+/-SignA14 A13 A12 A11 A10 A09 A08 Character 1 Character Format for 16 Bit Pulse AccumulatorLow Order 8 BitsHigh Order 8 BitsPA07 PA06 PA05 PA04 PA03 PA02 PA01 PA00 PA15 PA14 PA13 PA12 PA11 PA10 PA09 PA08 Character 1 Character SCAN FUNCTION 00 - BASIC SCAN FUNCTION SCAN FUNCTION 00 returns data to the MASTER STATION for a particularCOMMAND BYTE when it is desired to get all of a particular type of data returnedfrom a scan request without the necessity of specifying SEQUENCE NUMBERS.

10 Foreach of the command byte bits that are set, the RTU will return all of the specifiedtype of data with its response. (See for description) Description7060504030201000706PA5003 SBA22BS100 SSFunction CodeCommand11 FunctionCodeCommandBitFunctionRETURN ALL:00 Bit 00(SS)Simple Status Data00 Bit 010 ALWAYS - 0 - RESERVED00 Bit 02(2BS) 2 Bit Data Status00 Bit 03(SBA) 16 Bit Analog Format00 Bit 040 ALWAYS - 0 RESERVED00 Bit 050 ALWAYS - 0 RESERVED00 Bit 06(PA) 16 Bit Pulse Accumulator Data00 Bit 070 ALWAYS - 0 - BASIC SCAN OPERATION TYPICAL MASTER / REMOTE EXCHANGESThe following paragraphs illustrate the rules of the basic scan operation, along with some examples of its use. Data is always returnedby order of Sequence number (lowest Seq # first). Example 1 - FUNCTION 00/COMMAND 09. In response to this function,the RTU will return all simple status and all analog data in a 16 bit to Remote MessageAddressFunctionCodeCommand Number ofCharactersRA000900 00 CRCR emote to Master Response(Assumes 16 Status and 4 Analogs)Address FN S PS Numberof Chars0E 00 SimpleStatusAnalog1 Analog2 Analog3 Analog4 CheckCharsRA 00 S PS Lo Hi Lo | Hi Lo | Hi Lo | Hi Lo | Hi Lo | Hi Example 3 FUNCTION 00 / COMMAND 41.