Issue
A VIP with Modbus Slave Modules has been set up with a slave port added under Management Console > Tools > System > ION Virtual Processor Setup. The following error appears in the Management Console > System Log Events: "Unable to start VIP Modbus Slave communication. A license is required to use the VIP Modbus Slave feature."
Product Line
Power Monitoring Expert 7.x
Power Monitoring Expert 8.x
Power Monitoring Expert 9.0
Power Monitoring Expert 2020
Power Monitoring Expert 2021
Power Monitoring Expert 2022
Power Monitoring Expert 2023
Power Monitoring Expert 2024
Environment
VIP Modbus Slave
Cause 1
The VIP Modbus Slave feature requires the additional Data Exchange Module license, which isn't activated on the system.
Resolution 1
Confirm there is an active Data Exchange Module license shown in License Configuration Manager:
Cause 2
On PME 2021 or later, the service for the VIP with the Modbus Slave Modules is starting before the licensing service starts, causing it to not recognize the Data Exchange Module license and not initialize the Modbus Slave feature.
Resolution 2
1. Open Services and locate the ION Virtual Processor Service associated with the VIP that has Modbus Slave Modules
2. Right-click on the service > Properties
3. Set the Startup Type to "Automatic (Delayed Start)"
4. Restart the service
