why my DPH5005 voltage showing 00.01V

[pc1093]

why my DPH5005 voltage showing 00.01V

[m k]

Its probe is disconnected.
(wild guess)

[Medved]

And/or not calibrated exactly.
There should be somewhere a calibration manual, the calibration uses to be acessible from the front panel controls + the input power switch (some crazy combination of "hold these two keys while turning the power ON" or something along these lines). You need just an accurate multimeter, plus maybe some 1 Ohm power resistor (to not calibrate the current with a hard short, as that tends to lead to regulation inaccuracy).

But in any way, I'm pretty convinced it is still within the specified tolerance (uses to be +/-(few 10's of mV + few %), you have to count with that error any time you are using it even when it displays 0).