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345 TRANSFORMER PROTECTION SYSTEM – COMMUNICATIONS GUIDE
ETHERNET INTERFACE
CHAPTER 1: COMMUNICATIONS GUIDE
The contents of register 40172 are shown as the two byte values of 00 FE hex, or254
decimal. The contents of registers 40173 to 40175 are 00 04, 00 00 and 00 00 hex, or4, 0
and 0 decimal.
04H Read Input Registers
Reads the binary contents of input registers (3X references) in the slave.
Query
:
The query message specifies the starting register and quantity of registers to be read.
Registers are addressed starting at zero: registers 1 to 16 are addressed as 0 to 15.
Here is an example of a request to read register 30305 from slave device 254:
Response
:
The register data in the response message are packed as two bytes per register, with the
binary contents right justified within each byte. For each register, the first byte contains the
high order bits and the second contains the low order bits.
05H Force Single Coil
Forces a single coil (0X reference) to either ON or OFF.
The query message specifies the coil reference to be forced. Coils are addressed starting at
zero: coil 1 is addressed as 0.
The reguested ON/OFF state is specified by a constant in the query data field.
Field Name
Hex
Slave Address
FE
Function
03
Byte Count
08
Data Hi (Register 40172)
00
Data Lo (Register 40172)
FE
Data Hi (Register 40173)
00
Data Lo (Register 40173)
04
Data Hi (Register 40174)
00
Data Lo (Register 40174)
00
Data Hi (Register 40175)
00
Data Lo (Register 40175)
00
Field Name
Hex
Slave Address
FE
Function
04
Starting Address Hi
01
Starting Address Lo
30
No. of Points Hi
00
No. of Points Lo
01
Field Name
Hex
Slave Address
FE
Function
04
Byte Count
02
Data Hi (Register 30305)
80
Data Lo (Register 30305)
80
