P-2: Modbus Master Programming (Modbus RTU)
Instructions
The CLICK PLUS PLC has two instructions to exchange data with external Modbus devices
through the com ports; the Receive and Send instructions.
• Receive instruction: Read data from an external Modbus device.
• Send instruction: Write data to external Modbus device(s).
To use these instructions, double click Receive or Send in the Instruction List window as
shown below.
Select the Com Port that you are going to use and confirm the Protocol is MODBUS.
If the Protocol is not MODBUS, click the Com Port Setup button to open the Com Port Setup
Details window and change the Protocol to MODBUS. If the Protocol selection is grayed out
as shown below, it means the Com Port is used by another Receive and/or Send instruction in
the ladder program. You cannot change the Protocol setup until you delete those instructions.
Select the Com
Port to use.
Protocol needs to
be MODBUS.
Grayed out
P-2
Double click Receive or Send
in the Instruction List to use it
in the ladder program.
Instruction List
CLICK PLUS PLC Hardware User Manual, 1st Edition, Rev. B – C2-USER-M
4-31
Chapter 4: PLC Communications
