If the IPLC does not communicate via the Ethernet port (the LEDs on the port do not light up) and the controller performs a control task and communicates with other I/O modules, the low supply voltage may be the cause of the non-functional Ethernet communication. As soon as this voltage falls below the value stated in the datasheet (eg in our measurments it fluctuated between 8-10 V), IPLC runs the project, but the Ethernet port is turned off. For IPLC, the catalog supply voltage is at least 12 V dc. For modules that switch relays, this can be more - see the catalog sheet for the relevant I/O module.
