STEVAL-XPLM01CPL Power line communication AC coupling circuit

The STEVAL-XPLM01CPL is a simple yet very useful tool for power line communication testing on AC power networks.

It includes simple two-wire connectivity to any PLC transmitter/receiver and a standard connector for an AC power cord (2-pin AC plug, 8-shape female end). The main components to achieve suitable signal coupling are:

- PLC 1:1 transformer for differential coupling and basic electrical isolation

- SM6T15CA 600 W Transil +320 V ac varistor for effective protection against ESD, EFT and surge disturbances from the power line

- High voltage AC blocking capacitor with X2 safety class

- Tuning series inductor to adjust the frequency response

The STEVAL-XPLM01CPL can be very easily interfaced with the X-NUCLEO-PLM01A1 to test PLC communication performance over an AC mains network.

The frequency response of the coupling circuit is wide enough to fit any narrow-band PLC signal under normal test conditions. However, it can be easily adjusted by changing only the tuning series inductor L1.

The STEVAL-XPLM01CPL is suitable for lab measurements using equipment like an isolated probe for an oscilloscope or a spectrum analyzer, or to inject a signal from an arbitrary function generator.