I purchased 2 of these modules. From the data sheet for the ACS37800 I have calculated that the R Sense value should be 2.7K ohms. This was arrived at as follows, voltage measured is up to 250VAC RMS so a safe margin would require 1.4142 x 260 = 353.55, R SENSE = (4,000,000 x 0.25)/(367.69-0.25) = 2721. I fitted a 0.1% accuracy 2.7K ohm resistor in place of the one fitted and connected LO to the neutral line of single phase AC.

Having implemented the library, I can read the VRMS and IRMS measures, however, with no load (therefore no current) IRMS is 0.06A and VRMS is 373VRMS whereas my DMM reads 246VRMS - 2 questions; what could be the reasons that the voltage reading exactly 1.5 times what it should read and why is the current reading offset from zero?