Preset Multiple Registers - CAL Controls 3300 Communications Manual

2.4.3
Byte No
1
2
3
4
5
6
7
8
An error response code 2 (illegal address) will be returned if the bit is not a valid writeable bit,
otherwise the response is the same as the above message.
2.4.4
Byte No
1
2
3
4
5
6
7
8
The normal response is the same as the message. An error response code 2 (illegal address)
will be returned if the address is not within the processor bounds.
2.4.5
Byte No
1
2
3
4
5
6
7
8
9
10
11
note that this function is a subset of the normal ModBus function code 16 in that only one register of up
to 2 bytes may be written. Thus byte numbers 5, 6 and 7 must be as shown, otherwise an error
response with error code 1 (illegal request) will be returned.
COMMERCIAL IN CONFIDENCE
Force Single Coil (write single bit)
Meaning
Slave address
ModBus Function code (force coil)
Starting Address MSB, always 00, all bits are in internal
memory
Starting Address LSB
Force Data MSB (FF sets the bit, 00 clears it)
Force Data LSB (always 00)
CRC lo byte
CRC hi byte
Preset Single Register
Meaning
Slave address
ModBus Function code (write register)
Starting Address MSB
Starting Address LSB
Data MSB
Data LSB
CRC lo byte
CRC hi byte

Preset Multiple Registers

Meaning
Slave address
ModBus Function code (write register)
Starting Address MSB
Starting Address LSB
Number of registers MSB
Number of registers LSB
Number of bytes to follow
Data MSB
Data LSB
CRC lo byte
CRC hi byte
Page 12
Value (hex)
xx
05
00
xx
FF or 00
00
??
??
Value (hex)
xx
06
xx
xx
xx
xx
??
??
Value (hex)
xx
10
xx
xx
00
01
02
xx
xx
??
??