Fairford Electronics QFE Series, Manual

Page: 183 / 194

Modbus
page 6-6
5MC
FD510007
6.3 Specification
1. Refer to Modicon Modbus Protocol Reference Guide PI-MBUS-300 for full protocol
specification.
2. Baud rate is 9600.
3. 8 data bits, no parity, 1 stop (default) or 8 data bits, no parity, two stop bits.
4. Modbus timeout is 3.5 character times, the in message timeout is also 3.5 character
times unlike the standard which is 1.5 character times. Further it is also possible that the
5MC will be appreciably delayed in responding to a telegram if it is checking a fault condition.
5. Broadcast is not supported.
6. 5MC parameters retain their normal numbers (0-127).
7. Flag parameters are bit positions starting at parameter 0 bit 0
8. Register numbers are 0…127
9. Coils (flags) 0…1024
10. Offline eerom Registers are 1000…1127
11. Supports
Function 03 read holding registers up to 4 words (8 parameters) in number.
Function 05 preset single coil.
Function 06 preset single register (byte).
Function 07 exception status.
Function 16 preset multiple registers upto 3 words (6 parameters).
Error 01 illegal function (write to read only parameter)
Error 02 illegal data address (bad parameter number)
Error 03 illegal data (trying to read or write too much data)
Error 06 slave busy
Error 07 negative acknowledge