Hi,
I’m eagerly awaiting my new iotawatt to set up in my house and I had a few questions that I can’t seem to completely find the answer to.
Is port 13/14 only for reference? Can you measure with these ports? When I ordered I was only allowed to order 12 clamps.
I have 12 fuses I want to measure, I would also like to measure the intake (3x63a intake, Norwegian TN, no neutral) and I’m wondering if I can use port 13/14 for that. I already measure from the Han port with another device, this is cloud based and not always stable so, I would like to change it out.
Do I need to use the 9v supply If I use port 13/14?
Ports 13 and 14 are dual use. Each can be used as either an input for a current transformer using the 3.5mm jack or as an input for a voltage reference using the 5.5mm barrel plug.
The store allows up to 12 50A CTs with the Generic kit but allows additional 100A which you would need for 63A mains.
As with all three-phase service, you can use the direct reference method using ports 13 and 14 for additional voltage reference, or you can use derived reference where the unit uses one voltage reference and measures all three phases using that voltage. The overwhelming number of users employ derived reference with satisfactory results.
Three-wire three-phase is relatively rare, but not a problem. The mains can be measured using two or three CTs. When using two CTs, you will not know the total usage of each individual phase, only the total of all three. With three CTs, you will know the total usage of each phase and can effectively know the “unmeasured” component of each phase by subtracting the measured circuits from the total of each phase. You can use ports 13 and 14 to measure total mains using two 100A CTs.
The 9VAC is not a power supply. It is a voltage reference. You must have at least one voltage reference. If you have one reference at port 0, you can use derived reference to measure all of your three-phases.
Thank you for the quick and consise answers! , then I will order a couple more 100a clamps.
Could you tell me, for the 9 volt reference, I can’t seem to figure out if the centre is negative or positive on the plug, I’m trying to source one locally or potentially I already have one.
The reference transformer is AC, and so there is no polarity. The web store has links to source the transformer. I recommend using the Ideal 77DE-06-09 because it is a menu pick to configure in IoTaWatt and the phase-shift is known and calibrated.
, then I will order a couple more 100a clamps.