ProSoft Technology PTQ-AFC - Manual (Page 85)

PTQ-AFC ♦ Modicon Quantum Platform Quick Start
Liquid and Gas Flow Computer for Hydrocarbon Products User Manual
ProSoft Technology, Inc. Page 85 of 259
June 23, 2011
6.9 Modbus Communication
A remote Modbus Master device can be connected to any one of the
communication ports for data polling. The module accepts the following Modbus
command functions according to the Modbus protocol specification:
Modbus Function Code Description
3 Read Holding Registers
4 Read Input Registers
6 Preset (Write) Single Register
16 Preset (Write) Multiple Registers
Ports 2 and 3 support RS-232, RS-422, or RS-485 communications. The
Configuration/Debug port (Port 1) supports RS-232 only.
Refer to Cable Connections (page 133) for wiring instructions.
The Modbus Master command can be sent to either the Primary or Virtual
Modbus Slaves in the module. Each slave has individual Modbus addresses that
you can configure (Project / Site Configuration). The Primary Slave address is
configured as 244 by default.
6.9.1 Communication Parameters
The module supports the following communication parameters for each
communication port:
Parameter Values
Baud Rate 300, 600, 1200, 2400, 4800, 9600 or 19200
Data Bits 7 or 8
Stop Bits 1 or 2 Bits
Mode RTU or ASCII
Parity None, Even or Odd
Note: Do not configure a port for both RTU mode and 7 data bits as this combination is not
supported by the Modbus protocol.