The charger parameter can be get from the OCPP 1.6 message GetConfiguration.req message so Try to send a GetConfiguration.req from CSMS -> CS and the charger should going to send GetConfiguration.conf for all the configured parameter inside charger for OCPP communication.

Also if you want to specific fetch the data of meter reading like energy, power, and all then those will be send while transaction is running in MeterValue.req of OCPP message.