Pilot Communications SPM93 - Read Holding Registers (Function Code 03 H); Request Packet; Response Packet

34
address
address
01H (Function Code)
1 byte
01H (Function Code)
1 byte
Starting address
2 bytes
Byte num. (N)
1 byte
Relay num.
2 bytes
Relay status
N bytes
CRC check code
2 bytes
CRC check code
2 bytes
N = output num. ÷ 8, if remainder ≠0, then N=N+1.
9.3.2. Read Holding Registers (Function Code 03H)
This command packet requests that the SPM93 responds all valid registers. The
value of reserved registers is 0.
Request Packet
(Master→DFPM93)
Response Packet
(DFPM93→Master)
Unit ID/ Slave address
1 byte
Unit ID/ Slave address
1 byte
03 H (Function Code)
1 byte
03 H (Function Code)
1 byte
Start register address
2 bytes
Byte num.
(2 * register num.)
1 byte
Registers num.
2 bytes
First register data
2 bytes
CRC check code
2 bytes
Second register data
2 bytes
... ...
CRC check code
2 bytes