MODBUS Master Special module program Service

Outline

General information

CM1-SC01A/SC01B/SC02A cards are used for this service, which is the protocol using RS232/485 MODBUS Master to exchange data between the Slaves. The specifications are as follows.

Maximum connectable Slaves: 128 units.
Easy to recognize to communicate successful or not with result bits of communication.
Sequnce program is not necessary when periodic communication.
It is Flexible for Slaves supported variable commands
To communication in special events is possible with command, "SEND"”

CAUTION, identify a version of program for MODBUS Master special program. If it cannot support program as lower version, please make sure whether it is the recommend version

	CICON	CM1-CPxx(CPU)	CM1-SC0xx
Version	V1.89	V1.56	V1.40

Supported MODBUS RTU commands

Command	Substance	Remark	Domain
1 (Read Coil)	Read the bit device coil	Read Bit	0X
2 (Read Input)	Read the bit device input	Read Bit	1X
3 (Read Holding)	Read the word device holding register	Read Word	4X
4 (Read Input)	Read the word device input	Read Word	3X
5 (Force Single Coil)	Write the bit device coil	Write Bit	0X
6 (Preset Single Register)	Write Accesses the word device register	Write Word	4X
16 (Preset Multiple Regs.)	Write the word device register	Write Word	4X

SETTING UP COMMUNICATION CARD

To run MODBUS Master function, the parameter have to be set up in the special module setup. After running the CICON, select the
menu [ tool - Special Module Setup – RS232C/422 module...]
Please select "MODBUS Master Program".

REGISTER SPECIAL PROGRAM

Start scan program

Select [NEW program – MODBUS/RTU Master Program], and register program name.
Select the [OK] button.

MODBUS_RTU dialog box will appear, set up a device.

Base: This is used select the base of MODBUS/RTU Master module configured.
Slot: This is used select the slot of MODBUS/RTU Master module configured.
Ch : This is used select the channel of MODBUS/RTU Master module configured.
Result: This is used to appear the send/receive data’s result of communication frame.

result	Frame No.	The comm. Result Flag		The comm. Result Flag Running
		Succeed	Fail	Succeed	Fail
M0000	0	M0000	M0080	1 Scan On	On at all times Off at communication flag success
	11	M000B	M000B
	127	M007F	M007F

Example of configuration " result " M0000

REGISTER COMM. BLOCK

Dest. Station. : This is used to select a station number of RTU MODBUS Slave configured, In case of connecting between several slaves used through RS422/485 communication, the station number have to be different between slaves each other.
Function : This is used to select a suitable function when a data read/write between slaves. Please refer to the manual of "Command"
Point Number : Resister read/write domains referred to a address table of slaves. Please refer to " Address table in SLAVE "
Start Address: It is used to register the address of a read/write domain which is referred to address tables of slave. Please refer to the manual of " Address table of slave "
Data Type : This is used to select a type of send/receive data between slaves. Only selected analog data (Function 3, 4, 6, 16), they are valid

Scale Vector: Not Necessary
Data Count: This is used to set up a count of read/write slaves data.

Command(Function)	Data Size
1 - Read Coil Status 2 - Read Input Status	Bit Size
3 – Read Holding Registers 4 – Read Input Registers	Word Size
5 – Force Single Coil	Not Necessary.(1Bit Write)
6 – Preset Single Registers	Not Necessary.(2Byte Write)
16 - Preset Multiple Registers	Word Size

device: This is used to select a device address of send/receive data stored.

Function	device	Substance
Read Function	D0000	Address stored receive data between slaves
Write Function	D0010	Address stored send data between slaves

Do not transmit Automatically : This is used to communicate the block configured MODBUS RTU Master program sequencely(0~15). When you don’t use this function, check the blank. It is possible to receive data if only SEND command when check the blank,

Example of MODBUS RTU Master Special Programming Communication

Following picture shows slaves, communication system and frame structure which supported CIMON-PLC and MODBUS RTU Protocol.

[Information of slave ]

Parameter of slave	Substance
Comm. Protocol	MODBUS RTU protocol(Slave)
Comm. Type	RS232C
Station	1
Baud Rate	9600bps
Parity	None
Data bit	8
Stop bit	1

[ Address table of slave ]

Address	Substance	PLC device address
00001	PV(present)	D00000
00002	SV(set value)	D00010
…	…	…

EXAMPLE OF REGISTE

Register " special module setup ". Please refer to " Communication Setup "

Register " a communication parameter of slave" . Please compare to " special module setup " whether it’s the same or not.