The Rigol is my first "proper" bench PSU.
I always wondered what the RUN/HOLD button was for, other than lighting up in RUN, extinguishing in SINGLE (which does actually hold its reading), and flashing when in HOLD (which doesn't
seem to hold anything at all). Reading the Chinglish documentation made mention of some formula and the settings of 0.01% - 10% in the trigger setup.
Testing with a PSU it does indeed "hold" the reading on the display until the voltage falls outside the window. For example, set the trigger to 10% and measure 10V then lower the PSU voltage. The display won't change until the PSU drops below 9V (including removing the test leads) or rises above 11V. However, it still appears to trigger anyway and records the "false" held readings in the history log. I would have thought if it was any use at all it wouldn't record more than the initial decided on "held" reading and stop recording until a measurement outside of the held range is triggered.
I just put this down as a feature important to proper electronics engineers far more worthy and knowledgable than me. I mean Rigol dedicated a whole backlit button to it and made it flash!
I recently got a Keithley 2015 and decided to give it's Hold a whirl. What do you know? It is utterly brilliant. It has the same window settings of 0.01% - 10% along with a sample count (default 5). Not only does the trigger actually work as in it only records the held reading once, but when you take the leads off it only freaking actually HOLDS the reading on the display until you go and probe somewhere else. You just place your probes wait for the beep and go and look at the display with the probes removed. The Rigol just shows the 0 volt noise like it does in regular RUN mode here.
So... WTF is this function for on the Rigol, and why has nobody else brought it up? Now I know what it should do it's implementation is an utter joke. Unless someone can tell me otherwise?