# Current sense in a photovoltaic system - explained

hello Bob,

in a PV system , i need to detect sens of current in a circuit that is monitored with IOTAWATT, mens to have current with sens + when i consume power from circuit and current with sense - when i inject in circuit .
i realy see that power measurement for this circuit have sense +/- acordingly with sense of the current thourough circuit , but unfortunately for current i don t detect sign +/-.
all those values, with +/- i need to transfer to EMONCMS to make necessary calcules for energy used or injected.
please, can you help me ?

IoTaWatt will automatically make a negative power positive. To get the true signed power when there is bidirectional flow, check the “allow negative values” box in the input setup for that CT.

Hello Bob,

i clear sow this option on the menu of IOTAWATT, but acting in this way is nothing change when i send information to the EMONCMS , as well visualized current informaton as a value in output of IOTAWAT.
more clearly, on the OUTPUT STATUS, current will be all time positive as well as the value send to the EMONCMS.

in attached pictures we can see negative power value for VICTRON devices per phase, but positive value for current of VICTRON devices per phaseș, option for allow negative values is activated.

I misunderstood your question. I assumed you were talking about Watts. Amps are measured in RMS. Mathematically it is always a positive value.

truly,i was talking about sense+/- of current/amps in order to be used in mathematic calculus.
it is possible to have distinction between pozitive value and negtive values of current/amps ?
how is possible to can realize what i ask from begining , means to can measure injection in a system or energy used from system?

IoTaWatt measures electrical energy in kW. That is a signed quantity depending on if the energy is flowing into or out of the system.

The problem with using amps is that they can flow into and out of a system within a single AC cycle when there is reactive power. Im not aware of any way to determine the net energy into or out of a system using RMS Amps.