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TN DA127 Using PortQry to Diagnose PLC Port Status

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This article covers how to use the PortQry tool to troubleshoot the status of a PLC port.


  • Author: Daniel London
  • Published: 06/10/2015
  • Applies to: PortQry (All Versions)



When unable to communicate with a PLC, you can use PortQry to check and see if the port is open to the device.


Download PortQry Here:


  1. Run the installer to download the software.
  2. Extract the files to the C (root drive) of your hard drive.
  3. Once downloaded open Command Prompt.


In Command Prompt type the following to access Portqry: CD C:\PORTQRYV2



Next type the following command line to access the port you are querying:



Common PLC Ports:

DAS SI Direct:   102

DAS MBTCP:     502

DAS ABTCP:     2221, 2222, 2223

DAS ABCIP:      44818


The reply will be:

  • LISTENING: Indicates the PLC is listening on the port number specified.
  • NOT LISTENING: Indicates PortQry reached the PLC but the PLC is not listening on the port number specified. Check the PLC configuration. Also make sure the correct port is being queried.
  • FILTERED: Indicates PortQry did not receive a response from the target port and the target port is being filtered. A firewall may be blocking the port. Check hardware and/or software firewall configuration.