VC8145 thread ... It's here, finally

[Lightages]

Utter nonsense. The ACV range is limited. If you stay within 75% of the range and between 50Hz and 20kHz it's accuracy is 0.8% of the reading +/-50digits. This is better than my (4.5 digit) Agilent U1241B handheld DMM which already is at 2% at 2kHz. At least Vici took the effort to characterise their meter properly so you have some clue what the readings outside the specs are worth.

I don't think it is nonsense what alm pointed out. How is 8% accuracy considered good if you exceed 75% of a range? 50 counts out at any reading? I have a handheld meter here that costs just a bit more and has  better specs IMHO. It is a matter of opinion because the specs are stated differently. 50-60Hz; 0.5%+3D, 40-500Hz; <600mV 0.8%+4D, <100V 1%+4D, <1000V 2%+4D, etc, and never worse than 3%+4D up to 3kHz.

You try to write bad things about the VC8145 every time. This time about a post from 2012. Why did you dig that up, quoted the wrong specs and say it is a joke without any technical merit? I know you import multimeters into South America. Why don't you start selling the VC8145 over there as well? Or is your competitor killing you with it?

Actually, in spite of your vitriol, I have considered buying one of these many times. Investigation has stopped me each time. When did I misquote specs? You are saying that alm quoted was a lie? If so, please show how the specs provided by Vici contradict his statements. I think I stand on my assessment based on the technical merit as stated by Vici in their specifications.

I import and distribute for Brymen in most of South America. Brymen does not make bench top meters. How can anything I sell be in competition with a VC8145? Your accusation of shilling is unfounded and I didn't expect such an accusation from a person I thought was a reasonable and fact based thinker.

[Lightages]

Oh yes, from what I can see, the MASTECH MS8040 looks like a better buy. Sure it doesn't have 80,000 counts, but it seems to hold its accuracy better for the full range. This based on a reading of the specification of both and is not from experience. I think I would buy the MASTECH MS8040 over the Vici,and I don't like Mastech very much at all. But that is just my opinion.

[k2teknik]

As alm pointed out a long time ago, the AC measurement accuracy is horrible, worse than a joke. How do you guys reconcile that.

No problem, I can read the spec on the instrument and it is ok for me, I think other can do the same, and if they don't do so, just bad for them, you have to do your homework before you buy stuff no matter what stuff it may be.
It is not your decision to decide what is ok for me or other, your post stinks of professional jealousy.

[k2teknik]

Here are results of my reverse engineering attempt of the RS232 protocol: http://www.26th.net/blog/vichy-vici-vc8145-digital-multimeter-rs232-protocol/

Nice work, thank you.

[Wytnucls]

What is not specified in the specs is that, as the meter uses an AD737 true RMS converter, the first 10% at least of the AC ranges, are also unreliable. That doesn't leave much to play with.

[nctnico]

Utter nonsense. The ACV range is limited. If you stay within 75% of the range and between 50Hz and 20kHz it's accuracy is 0.8% of the reading +/-50digits. This is better than my (4.5 digit) Agilent U1241B handheld DMM which already is at 2% at 2kHz. At least Vici took the effort to characterise their meter properly so you have some clue what the readings outside the specs are worth.

I don't think it is nonsense what alm pointed out. How is 8% accuracy considered good if you exceed 75% of a range? 50 counts out at any reading? I have a handheld meter here that costs just a bit more and has  better specs IMHO. It is a matter of opinion because the specs are stated differently. 50-60Hz; 0.5%+3D, 40-500Hz; <600mV 0.8%+4D, <100V 1%+4D, <1000V 2%+4D, etc, and never worse than 3%+4D up to 3kHz.

You try to write bad things about the VC8145 every time. This time about a post from 2012. Why did you dig that up, quoted the wrong specs and say it is a joke without any technical merit? I know you import multimeters into South America. Why don't you start selling the VC8145 over there as well? Or is your competitor killing you with it?

Actually, in spite of your vitriol, I have considered buying one of these many times. Investigation has stopped me each time. When did I misquote specs? You are saying that alm quoted was a lie? If so, please show how the specs provided by Vici contradict his statements. I think I stand on my assessment based on the technical merit as stated by Vici in their specifications.

I import and distribute for Brymen in most of South America. Brymen does not make bench top meters. How can anything I sell be in competition with a VC8145? Your accusation of shilling is unfounded and I didn't expect such an accusation from a person I thought was a reasonable and fact based thinker.

Sometimes I need to tickle people a little.

Appearantly using the AD737 has a trade off. Vici appearantly choose to have accuracy over a wide frequency range (0.8% from 50Hz to 20kHz) and decided to live with the fact this chip doesn't support the full range of the input. Their decission results in a meter with a much higher accuracy over a wider frequency range than their competitors in the same price range. There is no denying that and I don't see why you have to be so negative about that because the slightly more expensive meter you quote is already at 3% at 3kHz. You can use the VC8145 for doing accurate measurements on audio signal levels. The meter you proposed is useless for that purpose.

@Whytenucls: That is probably why they specified +/- 50 digits. But this is an 80000 count meter so you can always reduce the range to get more digits as long as the result is less than 60000 in AC mode.

[Wytnucls]

The meter doesn't have a uA range. You can't measure less than 8mA RMS accurately.

[nctnico]

Welll..  At some point you have to spend more money. For measuring low currents you can use an external device like a shunt or Dave's uCurrent.

[Lightages]

It is not your decision to decide what is ok for me or other, your post stinks of professional jealousy.

I asked for opinions on how the stated specs are not a problem for others so maybe I could see things differently. In what way could I have professional jealousy in relation to the subject?

You guys are reading far too much into my opinion and a question. If I didn't want to know how the specs were not a problem and how I might have been mistaken, I would have not even bothered to post. 

[Lightages]

Appearantly using the AD737 has a trade off. Vici appearantly choose to have accuracy over a wide frequency range (0.8% from 50Hz to 20kHz) and decided to live with the fact this chip doesn't support the full range of the input. Their decission results in a meter with a much higher accuracy over a wider frequency range than their competitors in the same price range. There is no denying that and I don't see why you have to be so negative about that because the slightly more expensive meter you quote is already at 3% at 3kHz. You can use the VC8145 for doing accurate measurements on audio signal levels. The meter you proposed is useless for that purpose.

OK fair enough. Now I have a reason why the VC8145 could be better for some things despite the specs it has. Thank you for a rational and non-insulting answer.

@Whytenucls: That is probably why they specified +/- 50 digits. But this is an 80000 count meter so you can always reduce the range to get more digits as long as the result is less than 60000 in AC mode.

And thus the reason to know the limitations of your equipment. Everything has a trade offs. Personally, and IMHO, for me, my use, I could not live with this meter, for me, my use. Is that clear enough?

[dadler]

Don't be too offended by Lightages'(s?) opinion regarding DMMs.

He already hates another meter that doesn't even exist yet 

[Lightages]

Don't be too offended by Lightages'(s?) opinion regarding DMMs.

He already hates another meter that doesn't even exist yet 

[k2teknik]

You guys are reading far too much into my opinion and a question. If I didn't want to know how the specs were not a problem and how I might have been mistaken, I would have not even bothered to post. 

If you do not like this instrument then that is ok with me, but why do you have to post (repeat what you had told before) your comments when it has absolutely nothing to do with what was the tropic when you posted yesterday?

FYI, somebody was exchanging experiences about communication with the instrument, there was nothing about the instruments measurements spec. You have already told, a long time ago, that you dislike the thing, why do you have to repeat this?
The bad performance, spec. of the instrument had been debated for a long time and every body that wanted to masturbate over this had had there chance, why do you have to continue to make noise?

[Lightages]

So because I was reconsidering this meter once again, and I had a question on how to reconcile what alm had stated. If you bothered to read my explanation before making your statement about me it would have saved some time. So my question wasn't to your liking. Hmmm, let me see. This thread is about the VC8145 and I wanted to discuss it. I am sorry I transgressed your rules that this thread was only to discuss the communications protocols. I will remember to ask you if it is OK to post my opinion and questions here. Are there any other threads which you are lording over that I need your permission to post on?

[k2teknik]

So because I was reconsidering this meter once again

You never even try to reconsidering this instrument (why should you, you have most likely many other quality instruments to choose from), you just wanted to show off how clever and smart you are on quality measurement instrument, that is all you wanted.

This thread is about the VC8145 and I wanted to discuss it

No, bs, read my above comments.

I will remember to ask you if it is OK to post my opinion and questions here

You are lying, you will never ever follow my guidelines. I will even give you more advice, keep you sale talk in your own sales-room.

And, no, I do not feel insulted because some people speak badly about an instrument I own, I know that a low priced instrument comes with some trade off's on spec, functionality, stability and price. I do have quite a few other instruments, and with much better spec and acceptable labels on the front, to choose from, but it doesn't change that for some task my VC8145 is the best choice, or just good enough for the job.

[Lightages]

Sale talk? WTF am I selling? I guess you have a problem with English as this is the only reason I can think you would be attacking me personally. I am sorry you don't care to take me at my word. Have a nice life.

[nctnico]

@Whytenucls: That is probably why they specified +/- 50 digits. But this is an 80000 count meter so you can always reduce the range to get more digits as long as the result is less than 60000 in AC mode.

And thus the reason to know the limitations of your equipment. Everything has a trade offs. Personally, and IMHO, for me, my use, I could not live with this meter, for me, my use. Is that clear enough?

That is your choice but I can't shake the feeling you dismiss the VC8145 because the manufacturer printed an accuracy of 8% for a certain input signal range. Personally I appreciate a manufacturer for being that honest. Other manufacturers often don't print such numbers to keep make their products appear very accurate even though the range is very limited. Just try to find a DMM for the same price which has an accuracy of 0.8% between 50Hz and 20KHz. I don't think you'll find any. You'll have to go into the >$600 5.5 / 6.5 digit territory to find a DMM which matches that specifiction. IMHO the VC8145 is a real gem if you can look past the rough edges. The designers clearly put a lot of thought into which useful features they could put into it while keeping the price low.

[Lightages]

Fair enough. Like I said, now I see your point on why the specs are not as bad as they look from first glance. I perhaps did not word my opinion and question in a way that was how I really wanted to represent myself. So yes, it appears to be a very good meter for what purposes you have mentioned. If you are doing audio work and need a meter to handle this then it is even a better value. I overlooked this possibility and that is why I asked how to reconcile the specs.

I had other priorities in what I wanted so I made a choice to buy something else but if I need a second budget bench top meter it probably will in the running again.

[Wytnucls]

@ nctnico
You seem to dismiss the published specs of other manufacturers as fanciful, while accepting Vici's ones without question. I don't believe for one minute that the meter can achieve true RMS 0.8% accuracy all the way up to 20kHz. Did you test those claims?
When I do a meter review, I check the meter published accuracy against known standards and state the areas where it is lacking, with supporting figures. That is what most readers would expect, to form a valid opinion about any DMM.
Your short review brushes over the serious limitations of the meter and comes across as fanboism.
Most of the flaws had to be brought up by others, working from the manufacturer's manual.

[nctnico]

@ nctnico
You seem to dismiss the published specs of other manufacturers as fanciful, while accepting Vici's ones without question. I don't believe for one minute that the meter can achieve true RMS 0.8% accuracy all the way up to 20kHz. Did you test those claims?

You are also missing the point I'm making. Other DMM manufacturers use a true RMS solution which is accurate over the full input range but has a limited frequency span. These meters are clearly intended for work on mains. Vici however choose a solution which makes their meter suitable for audio work.

BTW: I just did a quick test with a sine wave at 1V RMS (8V range). The meter reading stays within 1% between 20Hz and 80kHz.

[Mayor C]

I don't know about this forum, I came here to learn about electronics, swap ideas and exchange techniques. I came to this thread to learn about an entry level bench multimeter. It is under $200 and does a lot of things reasonably well. What I see  instead in ten pages is about ten good posts, the rest are guys trashing the meter like people paid $2000 for it and puffing out their chest with huge superiority complexes. People posted that the box is empty, of course it is!!!  It was made to fit a certain footprint. People are trashing it because it doesn't do a good job on mains voltage, duh it is a bench multimeter, not really intended to go to the jobsite. I see people saying that you would be better off buying a used meter on ebay, not everyone can afford to gamble buying used equipment, this has a warranty, this does alot and will get them by, if they can afford more later they can always sell it and upgrade later. Very few people are saying anything constructive. k2teknik added some great comments as did alm and nctnico. For those with negative comments perhaps they could do comparisons with other bench meters in the under $200 category, that's what should done in a thread like this.

I don't no why the mods don't clean up this thread, take out 90% of the no use negative comments, this one too and get the forum going where it needs to be. Technical, not emotional.
This is just sad.

[Wytnucls]

Pfff. Two posts and already asking mods to clean up the site. This is Australia, where free speech prevails. Get used to it.

[Wytnucls]

@ nctnico:
You need to run that test again. Use a proper reference this time. A 1% RMS voltage accuracy at 80kHz with a 4 1/2 meter would make the headlines around the world, if it was true.
6 1/2 bench meters like the Fluke 8846A and Agilent 34401A barely manage 0.7% up to 100kHz.

The Vici manual says 0.8%+50 up to 20kHz and then 5%+50 up to 50kHz. Above that, accuracy should fall off the cliff.

If you maintain that your test is valid, perhaps you should make a video, so that everybody can rush and buy a VC8145 tomorrow.

[nctnico]

I don't have a leveled generator. The SDG1010's output level I used is flat within 1% up to 100kHz.

[sync]

6 1/2 bench meters like the Fluke 8846A and Agilent 34401A barely manage 0.7% up to 100kHz.

They are much, much better in real life. I made a quick test with my Keithley 2000 (calibrated 2008), HP 34401A (calibrated by myself) and for fun two low-end meters. Source is an old Russian B1-9 AC calibrator set to 1.00000V.

freq    K2000     34401A    UT-71C   UT-61E
  20    0.99963   0.99949   0.9877   0.9936
  50    0.99990   0.99973   0.9961   1.0001
 100    0.99997   0.99980   0.9975   1.0018
 200    1.00003   0.99991   0.9978   1.0028
 500    1.00003   1.00001   0.9982   1.0033
  1k    1.00006   1.00004   1.0003   1.0030
  2k    1.00006   1.00006   1.0043   1.0020
  5k    1.00009   1.00010   1.0089   1.0001
 10k    1.00010   1.00014   0.9962   1.0010
 20k    1.00017   1.00019   0.9811   1.0083
 50k    1.00015   1.00003   0.9826   1.0575
100k    0.99993   0.99964   0.9913   1.2083