ADMM-CP (VOM): R41 and High Source Impedance

Under conditions of very high source impedance or conditions that create a ground loop (other conditions apply as well), you may want to try removing R41 from the ADMM-CP (VOM) board (or testing with a board that doesn’t have it installed); if, after firmware updates and confirmation of measurement protocol, measurement values still seem inaccurate, …

ADMM-CP (VOM): Attenuated Mode

What it does The attenuated mode takes a real input voltage in the range of around +/- 14VDC and divides it down by about a factor of 10 so that it fits within the on-board ADC’s measurable voltage range of about +/- 1.4VDC. This is nominally and roughly. In a more detailed look, you might …