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TN DAS144 Monitor DAServer to PLC connection from InTouch



This article from InSource 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


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


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.


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


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"