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TN DAS144 Monitor DAServer to PLC connection from InTouch

Description

This article from InSource shows...how to monitor a PLC Connection from Intouch using $sys$status. This will allow you to know when the DAServer has lost connection to the PLC.

  • Author: Mike Viteri
  • Published: 05/19/2016
  • Applies to: Intouch & DAServers

Details

To monitor the status of the PLC to see if it is on the network. We will be using the tag $sys$status. This tag is built into all DAServers. We will be able to monitor this tag from Intouch.  

Here is a description of the tag:

   Item Name                       Description                                    Values

$SYS$Status

Boolean/Read Binary status
indication of the
connection state to the
device (hierarchy level)
the item is attached to.
The device group (OPC
access path/topic) does
not affect the value.

RANGE: 0, 1
1: DAServer connection
to the device is intact.
0: Error
communicating with
the device.

 

We will show an example of the tag in use.

  1. We are communicating to a Micrologix PLC using DASABCIP. We have an Accessname called PLC. We will create a tag inside of Intouch called DAMonitor(IO Discrete tag). 
  2. We have created a tag called DAMointor which is looking at the DASABCIP. It is liked to the item $sys$status which exists in the DAServer

3. We have created a value display discrete on an Intouch window.

$sys2.JPG

4.When going to WindowViewer you can see that DAmonitor tag is reporting the PLC as online.

$sys3.JPG

5. When the network cable is removed from the PLC or connection is lost. The $sys$station tag will be 0. The display updates to say "offline"