ProSoft Technology PLX31-EIP-SIE - Manual (Page 123)

PLX3x Series MBS Protocol
Ethernet and Serial Gateways User Manual
ProSoft Technology, Inc. Page 123 of 218
September 17, 2014
7.1.2 Modbus Master/Slave Port Specifications
Type Specifications
General Parameters
Internal Database Up to 4000 registers (words) available.
Communication parameters Port 0: Baud Rate: 110 to 115K baud possible
110 to 38.4K baud recommended for all applications.
Higher baud rates are recommended only for use
with very slow Modbus polling rates (e.g. 1command
or less per second)
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
Modbus Modes RTU mode (binary) with CRC-16
ASCII mode with LRC error checking
Floating Point Data Floating point data movement supported, including
configurable support for Enron implementation
Modbus Function Codes 1: Read Coil Status
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)
Modbus Master
Command List Up to 100 command per Master port, each fully
configurable for function, slave address, register
to/from addressing and word/bit count
Status Data Error codes available on an individual command
basis. In addition, a slave status list is maintained
per active Modbus Master port.
Polling of command list Configurable polling of command list, including
continuous and on change of data
Modbus Slave
Node address 1 to 247 (software selectable)
Status Data Error codes, counters and port status available per
configured slave port starting at memory register
4400.