American Control Technologies Datahopper 900 Radio via MVI56-MCM

Problem Solution Overview

We performed testing between the subject device and our MVI56-MCM (Rev 1.2) product.

Solution Brief

Our testing generated the following results:

• We were able to successfully communicate with the device. (See below for configuration parameters used during the testing)
• The product supported Modbus functions 3, 16. The slave radio device tested incorporated 2 analog inputs, 2 digital inputs and 2 digital outputs.
• Procedure used the sample MVI56-MCM Ladder Version 1.12 using RSLogix Version 8.02. No changes are made to the sample ladder provided with exception to the Port and Command definitions outlined below.

The purpose of our testing is to assure a level of compatibility in the communications between the two products. Through this testing, we attempt to identify problem areas that may arise when implementing the interface in the field.

Configuration:

The product testing was performed with the following settings used for both devices.
MVI56-MCM PORT 2 (set as Master)
- Baud: 9600
- Data bits: 8
- Parity: None
- Stop: 1
- Physical Connection: RS-232

The Module Configuration used in our testing was as follows:

Command List:

Device tested provides 2 analog values 40001-2, 2 digital inputs 40003 (low order bits) and 2 digital outputs 40004. The following command list shows some of the commands, which were used to test the communications:

Our test command list performs the following functions.

1. MCM.P2Cmd (0): Reads the values of the 3 input registers in the unit. This command READ 40001-40003 analog and digital I/O.
2. An exception error, 81-02 (illegal function) was issued by the unit when Function Code 1 was generated. This was an anticipated error and a test to the unit?s error handling capabilities.
3. An exception error, 83-03 (illegal data value) was issued by the unit when Function Code 3 was generated using a word count of 4. This was an anticipated error and a test to the unit?s error handling capabilities.

The above tests were achieved utilizing the debug port, built-in data analyzer.

Cable Connection:

The physical connection, which was used during testing, was as follows: