The Vmeasure circuit has both the standard 12 bit and a high performance 24 bit ADC (Analog to Digital Converter) that, under user control can add significantly higher resolution to Voltage measurements. This high resolution mode does come with a time penalty though since much longer integration times are required to stabilize a measure with this many bits of resolution.

There are 4 states available in the DutControl's 'voltage Meas Mode' button: "single', 'single-Hi Res', 'diff', and 'diff-Hi Res', for single-ended measurements and differential measurements respectively.

A sample test panel is shown here:

Note that this panel was written around an 11/1 voltage divider (1 kOhm over 100 Ohm) from DP12 to VM1. So when VCC1, through DP12, is swept from 10.89 to 11V, VM1 will see 0.99 to 1.0V

Here's a graph of the result, at 1 mV per division:


Narrowing the sweep range to be from 0.999V to 1.0V (1 mV sweep) yields the following, at 0.1 mV per division:

This shows that the random uncertainty, with the 5 averages specified in the test panel, is about 100 uV P-P. More averages may reduce that, but already the resolution is better than 100 uV.

Because of the high resolution/number of bits, this measurement is relatively slow. A single measurement takes up to 4 mSec, therefore with the 5 averages specified, this measurement total is about 20 mS per point.

Note that, if continuously measuring, there is a small amount of drift over time as the internal environment settles to a new ambient. On the 10V range, the drift is about 3 mV total, over about a minute.

To utilize the high resolution 24 bit measure feature, it requires a DC TIM RI8546C or later hardware and it also requires:
- Patch 277 dated 2014-04-06 or later.
- RiInstrumentDef titled 'Ri7421B Cassini Dut Control' and dated 2014-04-06 or later.

The High Resolution feature allows very high resolution voltage measurements for low level signals as well as on relatively high voltages.