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Writing to PSL Control Input elements using IEC 61850 MMS commands

MiCOM Px40 relays provide PSL Control Input logic elements which function as software switches that can be set or reset either locally or remotely. They can be set remotely using commands issued over the DNP3 protocol or commands issued over the IEC 61850 protocol. The inputs can be used to trigger any element that they are connected to as part of the PSL. The user manuals for the Px40 relays do not provide instructions on how to configure the relay to accept IEC 61850 commands in order to change the state of Control Input elements.

Product Line
MiCOM Px40 relays with Version 2 implementation of IEC 61850

MiCOM S1 Studio v5.0.0
Omicron IEDScout v2.11.0.171

The following Tutorial illustrates how to send a IEC 61850 MMS command to a Control Input logic element. This will have the effect of illuminating an LED on the relay front panel.


1. Configure the PSL within MiCOM S1 Studio as shown in the next figure. Do this by inserting the Control Input 1 element, inserting the FnKey LED1 element and connecting the two elements in the PSL workspace.

2. Save the PSL and send the file to the Px40 relay.

3. Configure the MCL file by setting the parameters for the Control Inputs signal(s):
  • Navigate the tree by selecting [name] >  Controls > Control Objects > System\PloGGIO1
  • Set the SPCO1 data object to direct-with-normal-security
Note: SPCSO[x] object is internally mapped to PSL Control Input [x] for all the Control Input elements.

4. In the MCL file configure the IP parameters of the Px40 relay IEC 61850 server, such that it belongs to the same subnet as the PC running the IEDScout software.
  • Navigate the menu tree by selecting [Name] > Communications to make the configuration changes.

5. Save the MCL file and send the file to the Px40 relay.

6. By opening the SET file ensure that the Control Input 1 element is set to Latched.

7. Save the SET file and send the file to the Px40 relay.


1. Connect to the relay via IEDScout and read the Px40 IEC 61850 device description.

2. Within IEDScout double click on the Data node of the navigation tree. This opens the Data View window.

3. Within the Data View window expand the data model tree by selecting SYSTEM > PloGGIO1 > CO.

4. To change the state of Control Input 1 right click on SPCSO1 and select Select Before Operate in the drop down menu.

5. In the Select Before Operate popup window change the lower drop down menu from F to T and then click the Operate command button.

6. Verify that the front panel LED next to Function Key 1 is now illuminated.

7. To turn off the Function Key 1 LED change the lower drop down menu of the Select Before Operate window from T to F and click the Operate command button.
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