I’ve been trying to integrate a PZEM-016 energy monitor which has a MODBUS connection, using an ESP-32 to interrogate it and send the data to my local EmonCMS running on a RaspberryPi. it finally started working when I realised that it was necessary to URLencode the GET variables or the POST body part, because the PHP GET/POST handler expects that for the JSON names e.g. “totalEnergy”:3333 becomes %22totalEnergy%22:3333.
It wouod be worth mentioning this in the documentation, the “input API help” on the Inputs screen doesn’t and neither do the EmonCMS docs. Unless I missed that…