Introduction

All Maple Systems HMIs programmed with EBPro (EasyBuilder Pro), including every cMT X Series and cMT Series model, are compatible with Modbus RTU (Adjustable). Configure your Controller and HMI/cMT with the following parameters to establish reliable communication.

Supported Series: MODBUS RTU CONTROLLER

HMI Settings

Parameters	Recommended	Options	Notes
PLC type	MODBUS RTU (Adjustable)
PLC I/F	RS485	RS232/RS485
Baud rate	9600	9600 / 19200 / 38400 / 57600 / 115200
Data bits	8	7, 8
Parity	Even	Even, Odd, None
Stop bits	1	1, 2
PLC sta. no.	1	0–255
Min. address	0		Note 1
Online simulator	YES
Extend address mode	YES

Note 1: Does not support communication with multiple devices with different minimum addresses.

PLC Settings

Parameter	Value
Communication mode	Modbus RTU protocol

Device Address

Bit/Word	Device Type	Format	Range	Memo
B	`0x`	DDDDD	1 ~ 65535	Output bit
B	`1x`	DDDDD	1 ~ 65535	Input bit (read only)
B	`3x_Bit`	DDDDDdd	100 ~ 6553515	Input Register bit (read only)
B	`4x_Bit`	DDDDDdd	100 ~ 6553515	Output Register bit
B	`0x_multi_coils`	DDDDD	1 ~ 65535	Write multiple coils
W	`3x`	DDDDD	1 ~ 65535	Input Register (read only)
W	`4x`	DDDDD	1 ~ 65535	Output Register
W	`5x`	DDDDD	1 ~ 65535	4x double word swap *Note 1
DW	`5x (32-bit)`	DDDDD	1 ~ 65535	4x double word swap *Note 4
W	`6x`	DDDDD	1 ~ 65535	4x single word write

Note 1: Please assign all the addresses to Even addresses, or all to Odd addresses, in order to prevent communication failure.

Note 2: EBPro V6.03.02 or later supports 64 bits data type (cMT Series only), but please note that the address limit range is 48 bits in maximum.

Note 3: Address Type 5x Mapping

Address type 5x is mapping to Hold Reg. The communication protocol of 5x is almost the same as 4x except that 5x swaps double words.

If 4x contains the following information:

Address	1	2	3	4	5	6	…
Data in word	`0x1`	`0x2`	`0x3`	`0x4`	`0x5`	`0x6`
Data	`0x0201`		`0x0403`		`0x0605`

For 5x, it will be:

Address	1	2	3	4	5	6	…
Data in word	`0x1`	`0x2`	`0x3`	`0x4`	`0x5`	`0x6`
Data	`0x0102`		`0x0304`		`0x0506`

Modbus RTU Function Codes

Device Type	Read Function	Write Function
`0x`	0x01 Read coil	0x05 Write single coil
`0x_multi_coils`	0x01 Read coil	0x0F Write multiple coils
`1x`	0x02 Read discrete input	N/A for writing operation
`3x`	0x04 Read input register	N/A for writing operation
`4x`	0x03 Read holding register	0x10 Write multiple registers
`5x`	0x03 Read holding register	0x10 Write multiple registers
`6x`	0x03 Read holding register	0x06 Write single register

Note: Reverse word order in double words format. 3x_Bit is equivalent to 3x; 4x_Bit is equivalent to 4x. 6x is limited to device of one word only.

Note 4: 5x (32-bit) × 2 − 1 = 5x

Comparison table showing 5x (32-Bit) and 5x address mappings with corresponding data values for double word swap behavior.

Setting Instructions:

Go to [System Parameter Settings]
click [New] to add a new device – MODBUS RTU (Adjustable)
Add Address Range Limit
After adding MODBUS RTU (Adjustable) driver, [Add Address Range Limit] button will be enabled. Users can set maximum read/write command size here.
MODBUS RTU (adjustable) usage
Users can decide the address range via setting value on [Min. address]. For example, when users set 5 to [Min. address], the address range will be 5 ~ 65535.

Wiring Diagrams

NOTE: The serial port pin assignments may vary between HMI models.

Diagram 1: RS-232

HMI	Direction	PLC
Pin assignments		RS232
Rx	↔ (bidirectional)	TXD
Tx	↔ (bidirectional)	RXD
GND	↔ (bidirectional)	GND
	↕︎ (tie)	RTS CTS

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

Connection Parameters Needed for HMI/cMT Products to Communicate with Modbus RTU (Adjustable) using EBPro (EasyBuilder Pro)