Allen-Bradley Communication Messages Dialog
The Comm Messages button will display the following information about an Allen-Bradley driver tag.
Displays the full driver name and version.
Data may be displayed in any of the 4 types shown.
Number Transmitted and Received provides a running count of messages in each direction.
Transmit & Receive display communications data using the data type selected above. The Index helps locate each byte within a message.
The Hold Data button will freeze the display. Otherwise the dialog updates continuously as messages are transmitted.
If you have the protocol information for the Allen-Bradley device, you can interpret each of the transmitted and received bytes to determine their meaning. The basic information that can be obtained from the Communication Messages window is that communications are proceeding as normal as long as bytes appear in both the Transmit and Receive columns.
If bytes appear in the Transmit column but not in the Receive column, VTScada is trying to poll the device for data (sending a read request), but the device is not responding. In this case it is wise to check the properties of the Allen-Bradley driver tag (station address, comm. channel, etc.) to make sure all settings are correct.
