I suspect on the one I borrowed the PSU was some sort of charger or small electronics PSU (potted plug type I didn't actually measure the voltage but it stated 22v so probably lower on load, I assumed though the low output from the analogue reduced the voltage who knows, I was intrigued though at a count of 4095 it was maximum (In my case 9.68v) but when pushed to 4096 the voltage dropped off to something like 14mv so it must be effectively a negative number as far as the conversion is concerned i.e. just like an integer but with it being 12 bit a/d it would effectively put out 0, The analogue input was pretty accurate I used my calibrated voltage source & that was pretty accurate. If I get chance I'm going to see why the CJ instructions seem to work with just one & not further CJ's I suspect that there is a difference between the clone i.e. old firmware versions vs more upto date FX3's.