Hello,
I’m working with the device 200193_EU, wich I bought at amazon https://www.amazon.co.uk/Multifunctional-Wireless-Voltmeter-Capacitance-Capacity/dp/B01LXJXUOA/ref=sr_1_3?ie=UTF8&qid=1487330986&sr=8-3&keywords=drok+dc+watt+meter , and when there is no load the current measure is 0A but when current is 20A, mesured with a clamp meter, the measure is about 29A so is there any way to calibrate the device?

Thank you very much.
I take the chance to ask if anybody has the user mannual can send it to me.