Schweitzer Engineering Laboratories SEL-587Z - 64 h Scattered Register Read; Controlling Output Contacts

D.12
SEL-587Z Instruction Manual Date Code 20020903
Modbus RTU Communications Protocol
Modbus Commands
The relay responses to errors in the query are shown below:
Controlling
Output Contacts
The SEL-587Z Modbus Register Map (Table D.18 on page D.16) includes
three fields that allow a Modbus master to force the relay to perform a variety
of operations. Use Modbus function codes 06h or 10h to write the appropriate
command codes and parameters into the registers shown in Ta b le D .18 on
page D.16. If function code 06h is used to write to a command code that has
parameters, the parameters must be written before the command code.
2 bytes Address of Second Register
••
••
••
2 bytes Address of nth Register
2 bytes CRC-16
A successful response from the slave will have the following format:
1 byte Slave Address
1 byte Function Code (64h)
1 byte Response Data Length
1 byte Subfunction Code (04h)
a
1 byte Transmission Number
2 bytes Data from First Register
2 bytes Data from Second Register
••
••
••
2 bytes Data from nth Register
2 bytes CRC-16
a
Only subfunction 04h is supported.
Error Error Code Returned
Communication
Counter Increments
Incorrect/Illegal
query data length
Illegal Data Value (03h) Bad Packet Format
Invalid subfunction code Illegal Data Value (03h) Illegal Function Code/Op Code
Illegal register address Illegal Data Address (02h) Invalid Address
Table D.14 64h Scattered Register Read Command (Sheet 2 of 2)
Bytes Field
Table D.15 SEL-587Z Modbus Command Region
Address Field
0090h Command Code
0091h Parameter 1
0092h Parameter 2