...would it be feasible to measure both without the relays to see the trends of both over time, or is the notion of compatible ranges more theoretical than practical? Thx again
You can only do graphs and trends on the primary measurement. What ever is set to the secondary measurement has no statistics available as far as I'm aware. You can of course swap between the primary and secondary measurements at any time, but whatever is set to secondary only gives you the numerical value at that moment in time.
You can graph the secondary measurement. Secondary measurements are written to defbuffer2 (you must be on defbuffer1 to use secondary measurements) so you go to MENU > Graph > Data > Add defbuffer2 as a trace. The Statistics swipe screen will only show stats on the active buffer (so the primary measurement), but you can see some buffer stats for the secondary measurement on the graph screen by switching traces.
How about the 10A range? - can that also potentially also be aligned with the other measurement?
For example, if you have a power supply that runs at 24V and anywhere from 400mA to 4A, if we aren't too picky about the axis label spans on the graph, would it be feasible to measure both without the relays to see the trends of both over time, or is the notion of compatible ranges more theoretical than practical? Thx again
There is no relay switching using the rear panel 10A input, and with the current range set to 10A. I just tested @20V with a load from 100mA to 3A. No relay clicking occurred. That is the best test I can do on short notice given the ranges you gave. Basically my power supply is 2x channel 20V, but only can sink up to 3A. While I could source 6A @ 20V, I don't have anything I can sink the current to get 4A. Although given that I was on the 10A range on the DMM, I see no reason to assume that this behavior would change at 4A.
Correct, relay switching is dependent on the range selected, it doesn't care what the actual measurement is.
On a related question, what's the longest I or V recording duration anyone has seen on the 6500? minutes, hours, days?
I've digitized at 1MS/s into a Continuous buffer for ~2 weeks. That's the longest I've done but I believe others have data-logged for longer, at least with integrated measurements, not sure about digitizing.
1. Can you see the V and I trendlines on the front panel display simultaneously?
Yes, the front panel swipe screen will show the graph you've configured on the graph screen, you don't have any ability to edit the graph from the swipe screen though.
How long (minutes, hours, days) can you record V and I?
You're only limited by the size of your buffer and the speed of your measurements. With a continuous buffer, you can theoretically record forever but you can't keep all the data as it's overwritten. The KickStart software is a solution for very long term data-logging, writing a script to handle creating csv files automatically is another potential solution.
How noisy really is the fan (how many dB at 1 meter distance?)
This one I don't know, I don't have a dB-meter unfortunately. It's one of the quieter instruments on
my bench, but other people seem to think it's louder than other products in its class. That's not really a spec we would publish because then we'd have to dB-meter all the instruments in an anechoic chamber.
(I think Keithley should make a video showing this for some plausible measurement values.)
Thank you for the ideas on the videos! I will add them to my to-do list...