Introduction

In industrial automation, seamless communication between a PLC and a robot is a crucial part of developing your machine. This article provides a step-by-step guide on how to configure variables in the NJR PLC and use them in a V+ script on the robot.

Configuring Variables on the OMRON NJR PLC

To facilitate data exchange, all variables that need to be shared must be configured in the Global Variable Table of the NJR PLC. The data types that can be shared with a i4H/i4L are:

BOOL (16-bit)

INT (16-bit)

UINT (16-bit)

REAL (32-bit)

LREAL (64-bit)

Fixed-length arrays (one-dimensional) of BOOL, INT, UINT, REAL, or LREAL with a maximum of 100 elements (range [0...99]).

Steps to Configure Variables in Sysmac Studio:

Open Sysmac Studio and navigate to the Global Variable Table.

Define the required variables using one of the supported data types.

Ensure the variables have unique and descriptive names to facilitate debugging.

Save and download the configuration to the NJR PLC.

Declaring External Variables in V+

On the EtherCAT robot, global variables that need to be used in a V+ program must be declared with the EXTERNAL identifier. This links them to the corresponding variables in the NJR PLC.

Example: Declaring a REAL Variable in V+

If a REAL variable named myReal is created in the NJR PLC, it must be declared in the V+ script as follows:

EXTERNAL myreal

This allows the robot to access the myReal variable as if it were a locally declared variable. Note that all variables in V+ are lowercase. If you define a variable as myReal on the PLC, you would refer to it as myreal in V+.

Reading and Writing External Variables in V+

Once declared, the external variables can be read and written like any other variable in V+.

Reading a Variable:

TYPE myreal   ;Display the value of myReal

Writing to a Variable:

myreal = 12.5   ;Assign a new value to myReal

Conclusion

By following these steps, you can successfully exchange variable data between an OMRON NJR PLC and an i4L/i4H EtherCAT robot. This setup enables efficient, real-time control and monitoring, essential for industrial automation processes.