IoTaWatt 9VAC Voltage Reference Transformer
Voltage Transformer Configuration
A prime component of electrical power is voltage. The AC line frequency is the heartbeat of the IoTaWatt. A reliable and accurate AC voltage reference is very important. You should have installed the device with a 9 Volt AC voltage reference transformer (VT) plugged into the channel zero power jack. If your initial configuration has this channel pre-configured, your LED will be glowing green because it’s rhythmically sampling that voltage.
Various transformer models produce different voltages, and it’s important to insure that the VT specified matches the model that you have installed. To do this, select the inputs button in the Setup dropdown menu.
A list of all of the inputs will be displayed. The first entry will be input 0 and a default VT should be configured. Check to see if it’s the same as your VT model. It’s OK to unplug the VT to check the model number printed on it.
If your VT model doesn’t match the model that is configured, you can easily change it. Click on the input channel 0 button on the left.
As you can see, the display changes to reveal the details of the input_0 configuration.
VT Model Selection
If your make and model is listed, select it from the list. At this point, you can just click 
and the standard calibration for your VT will be used. That calibration should be good for all but the most discerning users. If you have access to a good voltmeter or other reliable high accuracy voltage reference, you can fine tune with the calibration procedure below, but for average users, you should be good to go on to the next step Adding Power Channel CTs
If your VT wasn’t listed in the dropdown above, the generic entry is a reasonable starting point that will get you in the ball park for your 9-12Vac adapter. If your country is 230V or 240V select “generic240V”. Now you must perform the Voltage Calibration procedure below.
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