Technical FAQs

Ask a Question

PowerLogic SCADA Web Client Returns #COM and 'No Protection Key is Found' When the Loopback IP is Used in Network Addresses

Goals and Symptoms

When attempting to access the project in the web client for Powerlogic SCADA (PLS), all values return as #COM and a popup message of "No Protection Key is Found" is received. However, everything is functioning properly in Runtime on the server machine; there are no #COMs being returned.

Causes and Fixes

Ensure that the Loopback IP Address ( is NOT being used in the project. This includes the primary project AND any of the included projects.
To check:
1. Highlight the project in the Citect Explorer.
2. In the Citect Project Editor, click on "Servers" and select "Network Addresses"

3. Scroll through the Network Addresses and change any that are using the Loopback Address to the actual assigned IP address for the network card connecting to the system devices.
4. Repeat this process for all Included Projects.
Note: You can determine which projects (if any) are included in the primary project by clicking on "System" and selecting "Included Projects" in the Citect Project Editor, while the primary project is highlighted in the Citect Explorer.

The Loopback Address is convenient for testing purposes; however, it is highly recommended to use the actual assigned IP addresses for the Network Addresses when putting the project into Live Conditions. This is necessary because remote clients need to know where to look (which IP on the network) for data from the devices. If the Loopback Address is used in the project, remote clients look to themselves for data and for licensing, which results in the aforementioned behavior.

Keywords: PowerLogic SCADA v7.10 r01, r01.1, r01.2, PLS 7.1, Power SCADA, PowerSCADA, webclient, communication loss, software protection failure

Was this helpful?
What can we do to improve the information ?