Siemens SIMPRO-100 - Modbus Function Codes: Coil and Register Writes; 05 h Force Single Coil Command; 06 h Preset Single Register Command

SIMPRO-100
Modbus
™
RTU Communications Protocol
C
PRIM-2400C 161
C.3 01h Read Coil Status
Command
Use function code 01h to read the On/Off status
of selected bits (coils). You may read the status of
up to 2000 bits per query. Note that the relay
addresses inputs from 0. The relay returns 8 bits
per byte, most significant bit first, with zeroes
padded into incomplete bytes.
Table C.4 01h Read Coil Status Command
To build the response, the relay calculates the
number of bytes required to contain the number
of bits requested. If the number of bits requested
is not evenly divisible by 8, the relay adds one
more byte to contain the balance of bits, padded
by zeroes to make an even byte.
C.4 02h Read Input
Status Command
Use function code 02h to read the On/Off status
of selected bits. You may read the status of up to
2000 bits per query. Note that the relay
addresses inputs from 0. The relay returns 8 bits
per byte, most significant bit first, with zeroes
padded into incomplete bytes.
Table C.5 02h Read Input Status Command
To build the response, the relay calculates the
number of bytes required to contain the number
of bits requested. If the number of bits requested
is not evenly divisible by 8, the relay adds one
more byte to contain the balance of bits, padded
by zeroes to make an even byte.
Bytes Field
The Master Request must have the Following Format
1 byte Slave address
1 byte Function code (01h)
2 bytes Address of the first bit
2 bytes Number bits to read
2 bytes CRC-16 for message
A Successful SIMPRO-100 Relay Response will have
the Following Format
1 byte Slave address
1 byte Function code (01h)
1 byte Byte count
n bytes Byte count bytes of data
2 bytes CRC-16 for message
Bytes Field
The Master Request must have the Following Format
1 byte Slave address
1 byte Function code (02h)
2 bytes Address of the first bit
2 bytes Number bits to read
2 bytes CRC-16 for message
A Successful SIMPRO-100 Relay Response will have
the Following Format
1 byte Slave address
1 byte Function code (02h)
1 byte Byte count
n bytes Byte count bytes of data
2 bytes CRC-16 for message