Industrial Monitoring and Alarms | RACO®

Tip of the Month: Integrating MicroLogix to Verbatim Gateway via Modbus Protocol over RS232

Written by Eric | July 12 2011

The Verbatim Gateway system—interfaced with an Allen-Bradley MicroLogix family of PLCs containing a native Modbus RTU Slave driver—performs alarm and monitoring functions with existing wiring to PLCs as inputs via data communications.

In order to facilitate data communications via Modbus RTU Master/Slave over RS232 data interface, RACO provides a NULL Modem serial cable, VAB-1. This cable has the RJ-45 connector required for the system.

Below are instructions on how to integrate MicroLogix to Verbatim Gateway via Modbus Protocol over RS232.

Communication setup for Allen-Bradley MicroLogix:

1. Launch RSLogix Software

2. Set communications driver to Modbus RTU Slave

Open the channel configuration form and select an available channel other than zero where possible.

3. Select communication parameters

Any number between 2-256 is acceptable.

4. Select PLC data files

Available file numbers are 3, 7 and 9-255. Once a file number has been assigned, select the data type and name the file.

Communication setup for Verbatim Gateway:

1. Insert protocol driver NET ID

2. Choose a unique Modbus RTU Master/Slave DF1 NODE address

3. Select communication parameters to match driver settings on Modbus network

4. Confirm all preceding steps

5. Set NET ID and NODE/STATION address to default

Once the ID and address are set to default, it is not longer necessary to reference them when setting channel configuration.

6. Configure channel 1 and 2

After configuration, the channels are ready to be assigned to your project usually linked to alarm notifications, data logging and messaging.

7. Assign alarm conditions

Channel 1, configured as discrete, is either on or off. Channel 2, configured as analog, operates within range 0-65 and 535.

Click here for complete instructions on integrating MircoLogix to the Verbatim Gateway via Modbus or visit RACO’s Support Center for more information.