Rigol DM3058E Question: 2nd Function (Double Display) - Page 1
Forum section: electronics / testgear

author: xrunner
author_rank: Super Contributor
timestamp: December 24, 2013, 11:13:12 pm
content: I'm a bit confused by what the Chin-glish in the manual is trying to tell me regarding what the secondary screen area display capabilities can do.QuoteThere's also a chart that's confusing. It seems that the secondary display area can display a second property of the signal under measurement. OK, I got that, and I am able to understand that if you measure an AC signal, you can get the freq. of it in the secondary display, or the period. I've also got the secondary display to show me stats of the main signal, such as Max or Min., and the corresponding sensor input that's giving the translated output on the main display area.But the chart is what's confusing. Why would you want to pick DCV for the main display, and also DCV for the secondary display? Or, pick DCV for the main, and AC current for the secondary? How can you even measure AC current in the secondary display at the same time as measuring DCV? Makes no sense to me, but perhaps I just don't follow their explanation.Any clarifications appreciated. I've attached a screen shot of the chart from the manual.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: December 25, 2013, 11:12:45 am
content: It's a feature not present in the DM3068, but I would assume you can connect 2 signals to be measured in an alternating way.Also the latest Manual is Aug. 2012http://www.rigol.com/prodserv/DM3058E/document/

author: xrunner
author_rank: Super Contributor
timestamp: December 25, 2013, 12:49:22 pm
content: Quote from: KedasProbe on December 25, 2013, 11:12:45 amThe Rigol N. America site wanted me to set up an account to get the online manual, but of course it came with a manual on CD, and they say the same thing.But what do you mean it's a function not present in the DM3068? Here's a pic of the DM3068 doing just what I described. The DM3068 damn well better do it since it's more expensive! I checked the manual for it and it does do the same thing as the DM3058.I'll try to test it out, but it just seems weird that the manual doesn't explain it a little better. It just doesn't say up front in the basic description that "this meter can measure two parameters at once", and it still doesn't explain why you'd want two DCV in both windows, or DCV and ACV, since there is no possible way to connect two different V measurements at once.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: December 25, 2013, 02:02:18 pm
content: That is a photo of the DM3058 (see 5 1/2 text at the top)I know they show the wrong photo at the rigolna website. EDIT: (and the one at rigol is outdated)The matrix you are showing is only present in the DM3058(E) manual not DM3068.With DM3068 you can only select frequency as second measurement.(the second number is also used to display the calculated value of a sensor value)I assume the reasoning is that they had to give up some accuracy/stability for that function and you can do that on the DM3058(E) since its specs are lower, but not possible on DM3068.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: December 25, 2013, 02:24:31 pm
content: I think you should read that like this: in the DM3068 manualQuoteEdit: ah your post is gone. OK, anyway could help others not making that mistake

author: xrunner
author_rank: Super Contributor
timestamp: December 25, 2013, 02:26:57 pm
content: Quote from: KedasProbe on December 25, 2013, 02:24:31 pmYea I deleted my post because I was thinking that same thing. Nevertheless, I still don't understand what the whole matrix is telling me, such as why would you select DCV in both the main and secondary display? Why, why, why ...

author: KedasProbe
author_rank: Frequent Contributor
timestamp: December 25, 2013, 02:31:48 pm
content: Why not just try to connect the current and voltage terminal at the same time? (make sure not to swap them)

author: Unknown
author_rank: Unknown
timestamp: December 25, 2013, 02:33:55 pm
content: Quote from: xrunner on December 25, 2013, 02:26:57 pmBecause you enabled one of the math functions on one?

author: KedasProbe
author_rank: Frequent Contributor
timestamp: December 25, 2013, 02:37:40 pm
content: Quote from: alm on December 25, 2013, 02:33:55 pmMaybe or could the sense terminal be used as second voltage input?....

author: Unknown
author_rank: Unknown
timestamp: December 25, 2013, 02:43:47 pm
content: From the manual snippet xrunner posted:QuoteSo this seems a fairly useless feature.

author: xrunner
author_rank: Super Contributor
timestamp: December 25, 2013, 02:44:09 pm
content: Quote from: KedasProbe on December 25, 2013, 02:31:48 pmThe only current terminal available after you connect the meter to measure voltage is the 10 terminal.Quote from: alm on December 25, 2013, 02:33:55 pmNot sure, but I don't think so.

author: xrunner
author_rank: Super Contributor
timestamp: December 25, 2013, 02:49:29 pm
content: Quote from: alm on December 25, 2013, 02:43:47 pmRight, WTF is the point of looking at the same DCV presented two times on the same display? I might have to make a support call to get a person to 'splain it all in plain English.I selected DCV for main and DCI for second, and the meter did display both - but how do you connect the leads to accomplish the measurement? The DCI area displayed 0.000 uA. OK. So what. If I connect the test probes to a PS, it shows the DCV OK, but the current display shows Zero and still, how would you get a current measurement anyway? There isn't a separate current input (except for the 10 A input).

author: xrunner
author_rank: Super Contributor
timestamp: December 25, 2013, 02:54:20 pm
content: Hold on, I'm making up an experiment. I'll get back to this thread later today after the Holiday festivities.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: December 25, 2013, 02:55:02 pm
content: I assume one terminal will have to be common. (as a limitation)Should be ok to measure current and voltage of the PS.(set PSU to low max current, just to be sure)

author: xrunner
author_rank: Super Contributor
timestamp: December 25, 2013, 03:01:08 pm
content: Quote from: KedasProbe on December 25, 2013, 02:55:02 pmI think I'm holding a false assumption about what this meter can (or can't) do in my head. This is the first full-blown "modern" bench meter I've had and I think I'm assuming something about it that is wrong. Probably staring me in the face. Let me get back to this thread later today. Check back and I'll post my findings.

author: Unknown
author_rank: Unknown
timestamp: December 25, 2013, 03:01:39 pm
content: That's how it works on other meters that can measure current and voltage at the same time: connect the INPUT LO terminal to the negative output of the power supply, connect the INPUT HI terminal to the positive output and connect the 10A current terminal to the low side of the load (or the positive output if you're shorting a current-limited power supply without load).

author: iDevice
author_rank: Regular Contributor
timestamp: December 25, 2013, 04:24:30 pm
content: Quote from: xrunner on December 25, 2013, 02:49:29 pmI don't know if it's the same on the 3058 (too lazy to download the manual) but on my 3068, low current (200mA max) is measured between the two black terminals, the right one stays the common (negative) and the left one is positive.So technically, it would be possible to measure both current and voltage at the same time.I personally regret the 3068 doesn't have this feature, I would have swapped my extra useless digit for that...Unfortunately, I discovered it after the trial period.The same goes for the capability to measure both DC and AC components of a signal which I also miss.The 3068 is a very accurate DMM but you rarely need such precision anyway and I think the 3058 is much better value for general use.That said, it's not a big deal, as you generally have multiple generation of DMM in your lab anyway, so plenty of possibilities to measure several things at the same time, but I guess it's important to know if such bench DMM is your unique reliable instrument.

author: xrunner
author_rank: Super Contributor
timestamp: December 25, 2013, 05:20:03 pm
content: Quote from: alm on December 25, 2013, 03:01:39 pmIt was me - I assumed the terminal that said 10A was only for high current measurements like another DMM I have, but that isn't true. It's for all the current measurements. So that explains how it can work because all current measurements go into that terminal. I set up a very simple experiment using a 100 ohm R and 10V supply. You can see in the pic it does indeed measure both V and I at the same time (see both buttons lit). You just run the current through the meter and use an extra test lead to measure the voltage so you end up with 3 leads. Indeed a nice feature.Quote from: iDevice on December 25, 2013, 04:24:30 pmNo that's different than the 3058 for sure. That's what confused me because I was thinking the 10A red terminal was for high currents, but it's for ALL currents.QuoteYea I don't understand why the more expensive DMM can't duplicate the lesser one even if it was a menu selection that put it into a less accurate mode, if the user wanted to down-convert it to a DM3058. Must be some hard-wired road block inside that can't allow it to do the same thing as the 3058.Yet ... I still do not understand why you'd want to see two of the same DCV measurements on the screen. Some things must be left to ponder about.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: December 26, 2013, 11:14:48 am
content: Quote from: xrunner on December 25, 2013, 05:20:03 pmYou tried the sense terminal for the second voltage? Again with a common one. Like for -5V 0v 5V

author: xrunner
author_rank: Super Contributor
timestamp: December 26, 2013, 01:13:54 pm
content: Quote from: KedasProbe on December 26, 2013, 11:14:48 amNo I didn't, because nowhere in the manual does it say to do that. Granted it doesn't show in the manual an actual diagram of three leads as I connected doing a double V/I measurement, but these leads are connected to correct terminals. The sense terminal is for resistance measurement. I am reluctant to connect a voltage to one because I don't want to damage it. I'm going to contact tech support to ask the question.Really, I still to this day do not understand how a large international company based in China cannot simply hire ONE native English speaking person, or get a U.S. office to edit manuals, or a Chinese national that has a degree in English, to edit these manuals. Just read this examples -QuoteQuoteQuote

author: Bored@Work
author_rank: Super Contributor
timestamp: December 26, 2013, 01:49:39 pm
content: Quote from: xrunner on December 26, 2013, 01:13:54 pmBut that would mean one less ernai (expensive whore) for a top manager. Can't have that.QuoteOh, that they likely have. Only that the English degrees their writers have are apparently worth shit. Entirely made-up diplomas, obtained with cheating, or from One Hung Low 17th District University diploma mill and corruption training camp.

author: KedasProbe
author_rank: Frequent Contributor
timestamp: December 26, 2013, 03:02:42 pm
content: Quote from: xrunner on December 26, 2013, 01:13:54 pmThe sense terminal does have an label of Max 200V so that won't be for 4W R, but my DM3068 does have that label also, and I'm sure it won't work on mine.