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AD to CT Modbus Hookup Page 4

Now lets tackle setting up the PLC to transmit a MODBUS message. The setup is available WHEN ONLINE under PLC - Setup - Secondary COM Port.

Here's a picture of the window which opens.

Comm Port 2 Setup

The items which must be changed from the default are:

1. Uncheck K-Sequence and DirectNET
2. Set the baud rate to 19200
3. Set the Stop Bits to 2
4. Set the Parity to 'None'
5. Set RS-485 Echo Supression

Then click the "Arrow Pointing To PLC" symbol to send the setup.

These choices are mainly because they are the defaults in the CT equipment. There are no further setups in the CT equipment until you set up more than one drive. We'll cover that later.

The next posting will describe setting up communication rungs in the PLC. Stay tuned.

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Drive command wiring
The communication rung

Copyright © 2005, 2006, 2007 Bernard Carlton