Introduction
All Maple Systems HMIs programmed with EBPro (EasyBuilder Pro), including every cMT X Series and cMT Series model, are compatible with Modbus ASCII Server . Configure your Controller and HMI/cMT with the following parameters to establish reliable communication.
HMI Setting
Parameters Recommended Options Notes PLC type MODBUS ASCII Server PLC I/F RS232 RS232, RS485 Baud rate 9600 9600~115200 Data bits 8 7, 8 Parity Even Even, Odd, None Stop bits 1 1 PLC sta. 1 1-31 HMI Modbus Station No. Online simulator YES Extend address mode NO Broadcast command NO
PLC Setting
Parameter Value Communication mode Modbus ASCII protocol
Device Address
Bit/Word Device type Format Range Memo B LBdddd0 ~ 9998 Mapping to 0x/1x 1 ~ 9999 W LWdddd0 ~ 9998 Mapping to 3x/4x 1 ~ 9999 W RWddddd0 ~ 55536 Mapping to 3x/4x 10000 ~ 65536
LB0 = 0x0001, LB1 = 0x0002, LW0 = 3x0001, LW1 = 3x0002
NOTE: Modbus ASCII Server doesn’t support function code 06 (preset single register). Use function code 16 (0x10, preset multiple registers) instead.
Modbus Server Function Code
Register type Read Write 0x0x01 Read coil0x05 Write single coil0x (multiple coils)0x01 Read coil0x0F Write multiple coils1x0x02 Read discrete inputN/A 3x0x04 Read input registerN/A 4x0x03 Read holding register0x10 Write multiple registers
Wiring Diagram
Diagram 1: RS-232
HMI Direction PLC Pin assignments RS232 Rx ↔ (bidirectional) TXD Tx ↔ (bidirectional) RXD GND ↔ (bidirectional) GND ↕︎ (tie) RTS
Diagram 2: RS-485 4W
HMI Direction PLC Pin assignments RS485 4W Rx- ↔ (bidirectional) Tx- RX+ ↔ (bidirectional) Tx+ Tx- ↔ (bidirectional) Rx- Tx+ ↔ (bidirectional) Rx+ GND ↔ (bidirectional) GND
Diagram 3: RS-485 2W
HMI Direction PLC Pin assignments RS485 2W Data- ↔ (bidirectional) D- Data+ ↔ (bidirectional) D+ GND ↔ (bidirectional) GND
NOTE: Setting more than one Modbus ASCII Server in the HMI Device List is of no effect.
