CHAPTER 1: COMMUNICATIONS GUIDE
ETHERNET INTERFACE
345 TRANSFORMER PROTECTION SYSTEM – COMMUNICATIONS GUIDE
1–35
Response:
43H Write Settings Group
Not a standard function
This function is used to write settings in a specific settings group.
Example:
(In the example there is a write setting procedure in the Group 1 (00) , setting
address 0x09C1 and 2 bytes of data with value 0x0001.)
Response:
Exception and error
responses
One data frame of an asynchronous transmission to or from a 345 typically consists of 1
start bit, 8 data bits, and 1 stop bit. This produces a 10 bit data frame. This is important for
transmission through modems at high bit rates.
Modbus protocol can be implemented at any standard communication speed. The
SR350supports operation at 9600, 19200, 38400, 57600, and 115200 baud.
Request response
sequence
A complete request/response sequence consists of the following bytes (transmitted as
separate data frames):
Master Request Transmission:
SLAVE ADDRESS: 1 byte
FUNCTION CODE: 1 byte
DATA: variable number of bytes depending on FUNCTION CODE
Field Name
Hex
Slave Address
FE
Function
42
Byte Count
02
Data Hi
00
Data Lo
00
Field Name
Hex
Slave Address
FE
Function
43
Group Activation
00
Starting Address Hi
09
Starting Address Lo
C1
No. of Registers Hi
00
No. of Registers Lo
01
Byte Count 04
02
Data Hi
00
Data Lo
01
Field Name
Hex
Slave Address
FE
Function
43
Starting Address Hi
09
Starting Address Lo
C1
No. of Registers Hi
00
No. of Registers Lo
01
