PLX3x Series MBS Protocol
Ethernet and Serial Gateways User Manual
ProSoft Technology, Inc. Page 123 of 218
May 26, 2016
7.1.2 Modbus Master/Slave Port Specifications
Up to 4000 registers (words) available.
Port 0: Baud Rate: 110 to 115K baud
Port 1, 2, 3: Baud Rate: 110 to 115K baud
Stop Bits: 1 or 2
Data Size: 5 to 8 bits
Parity: None, Even, Odd RTS Timing delays: 0 to
65535 milliseconds
RTU mode (binary) with CRC-16
ASCII mode with LRC error checking
Floating point data movement supported, including
configurable support for Enron implementation
2: Read Input Status
3: Read Holding Registers
4: Read Input Registers
5: Force (Write) Single Coil
6: Preset (Write) Single Register
15: Force(Write) Multiple Coils
16: Force (Write) Multiple Register
22: Mask Write Holding Register (Slave Only)
23: Read/Write Holding Registers (Slave Only)
Up to 100 command per Master port, each fully
configurable for function, slave address, register
to/from addressing and word/bit count
Error codes available on an individual command
basis. In addition, a slave status list is maintained
per active Modbus Master port.
Configurable polling of command list, including
continuous and on change of data
1 to 247 (software selectable)
Error codes, counters and port status available per
configured slave port starting at memory register
4400.