E.14
SEL-751A Relay
Instruction Manual
Date Code 20100129
Modbus RTU Communications
Communications Protocol
The relay responses to errors in the query are shown in
10h Preset Multiple
Registers Command
This function code works much like code 06h, except that it allows you to
write multiple registers at once, up to 100 per operation. If you are
accustomed to 4X references with the function code, for six-digit addressing,
simply add 400001 to the standard database addresses.
Table E.16
06h Preset Single Register Command
Bytes
Field
Queries from the master must have the following format:
1 byte
Slave Address
1 byte
Function Code (06h)
2 bytes
Register Address
2 bytes
Data
2 bytes
CRC-16
Table E.17
Responses to 06h Preset Single Register Query Errors
Error
Error Code Returned
Communication Counter
Increments
Illegal register address
Illegal Data Address (02h)
Invalid Address Illegal Write
Illegal register value
Illegal Data Value (03h)
Illegal Write
Format error
Illegal Data Value (03h)
Bad Packet Format
Table E.18
10h Preset Multiple Registers Command
Bytes
Field
Queries from the master must have the following format:
1 byte
Slave Address
1 byte
Function Code (10h)
2 bytes
Starting Address
2 bytes
Number of Registers to Write
1 byte
Number of Bytes of Data (
n
)
n
bytes
Data
2 bytes
CRC-16
A successful response from the slave will have the following format:
1 byte
Slave Address
1 byte
Function Code (10h)
2 bytes
Starting Address
2 bytes
Number of Registers
2 bytes
CRC-16
Summary of Contents for 751A
Page 1: ...20100129 SEL 751A Feeder Protection Relay Instruction Manual PM751A 01 NB...
Page 6: ...This page intentionally left blank...
Page 12: ...This page intentionally left blank...
Page 18: ...This page intentionally left blank...
Page 26: ...This page intentionally left blank...
Page 92: ...This page intentionally left blank...
Page 218: ...This page intentionally left blank...
Page 250: ...This page intentionally left blank...
Page 376: ...This page intentionally left blank...
Page 392: ...This page intentionally left blank...
Page 408: ...This page intentionally left blank...
Page 418: ...This page intentionally left blank...
Page 434: ...This page intentionally left blank...
Page 462: ...This page intentionally left blank...
Page 544: ...This page intentionally left blank...
Page 580: ...This page intentionally left blank...
Page 584: ...This page intentionally left blank...
Page 632: ...This page intentionally left blank...
Page 636: ...This page intentionally left blank...
Page 640: ...This page intentionally left blank...