VC8145 thread ... It's here, finally

[Lightages]

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

I tried to find this spec listed somewhere. All I can find is that it is:

Vertical accuracy 100 kHz sine ±0.3dB+1mVpp of setting value
Amplitude flatness compared to 100kHz sine,5Vpp ±0.3 dB (or close to 3.5% if I calculated it correctly)

Did you actually measure the flatness of yours?

[nctnico]

I just Googled for the SDG1000 flatness spec and quoted the first I found. I guess Siglent changed the specs or measured them differently nowadays.

[inoxidabile]

Hi everybody ! 

I was looking for a software to the aim of connect VC8145 to pc.
The utility sent in the cd with the DMM was very bad, so I hope there is something better... I tried several softwares, like UltraDMM but no one runs. 

maybe someone could suggest me something (if any)?
Thanks a lot!

[k2teknik]

The utility sent in the cd with the DMM was very bad

Yes, especially if you have the character comma (,) as decimal separator in your windows OS setup, then the sw do not work at all.

maybe someone could suggest me something (if any)?

The SW for UNI-T UT70C works with the VC8145, except that the decimal point is in the wrong position (Uni-t UT70C is 8000 counts, VC8145 is 80000 count).

[pascal_sweden]

I recognize that the VC8145 does not have the same accuracy as the A-brand 6.5 digits meters, but do you really need that level of accuracy for most electronic projects?

If we assume that accuracy is good enough for most electronic projects, what are the real big deficiencies of the VC8145? Are we talking about missing features, safety issues?

I am happy with the build quality of the Vichy VC97 portable multimeter, and now consider the VC8145 bench multimeter as a nice addition. Not concerned about the accuracy, but want to check here about the big features I would be missing out, or what the potential safety issues are.

Note that I will only use it for low voltage applications limited in 100MHz bandwidth range.

Of course it would be cool to own a HP 3458A like this one for show-off

But definitely not in my budget and no need for the accuracy.

[Wytnucls]

Some people are perfectly happy using 10$ 3 1/2 digits DMMs for their projects. So, it's all about your needs and budget.

[SeanB]

+1 on that, I was using one today, as I wanted an extra meter to check while I had the other one in use. Always handy to have one or three around.

[Lightages]

I would say that the vast majority of people really don't need anything more than 3-1/2 digit (2000 count) multimeters. The extra digits and accuracy only really become useful for some very specific needs. I think that 10000 counts would be all that any general hobbyist would ever need. Of course there will be exceptions.

We are spoiled with a richness of cheap choices now.

[nctnico]

3.5 digits isn't enough. You need at least 4.5 digits. With 3.5 digits you are missing a part of the useful range. For example for 20V you need to select the 200V range with leaves 3 digits for display 20.0. With a usual accuracy of +/- 5 digits you don't know whether you are looking at 19.5V or 20.5V when the meter displays 20.0V. The accuracy of the reading is +/-2.5% in that case.

[pascal_sweden]

I noticed that the (-) terminal on the Vichy VC8145 displays a ground symbol.
Does that mean that this bench multimeter does not have an isolated front-end?

[Wytnucls]

3.5 digits isn't enough. You need at least 4.5 digits. With 3.5 digits you are missing a part of the useful range. For example for 20V you need to select the 200V range with leaves 3 digits for display 20.0. With a usual accuracy of +/- 5 digits you don't know whether you are looking at 19.5V or 20.5V when the meter displays 20.0V. The accuracy of the reading is +/-2.5% in that case.

Most 10$ meters go up to 4,000/6,000 count these days, with accuracies around 0.8%+3 digits. No real problem there.

[nctnico]

I noticed that the (-) terminal on the Vichy VC8145 displays a ground symbol.
Does that mean that this bench multimeter does not have an isolated front-end?

No. If you look closely you'll see the symbol refers to a line between + and -. It meens that there is a limit to input voltages and ground.

[inoxidabile]

@ k2teknik :
Hello, thanks a lot for suggestion!
The UT70D software runs well and i's good enough for a common use.
It's a pity for the wrong position of decimal point, as You said.

[k2teknik]

It's a pity for the wrong position of decimal point, as You said.

I found this sw https://www-user.tu-chemnitz.de/~heha/hs/UNI-T/ yesterday, it is more or less universal (for Uni-t products, and there is info on some Uni-t instruments RS232 protocols) I had just try it with the UT79D settings and it shows the right decimal point, but the logging is with wrong decimal point, but the sw looks better that the one from Uni-t and the one for the VC8145.

This sw should be able to use DDE with LabVIEW and MS Excel (maybe more?), but this out of my scope.

[inoxidabile]

I saw it some days ago, but in my pc sometimes it doesn't run (com port setup?)
Anyway, I agree with You, a great job of reverse enginnering has been done and I understand it (more or less) even if german it's not my language.
I think it could be used, maybe with some adjustements, moreover it's a confirm that the protocol for UT70D is correct for VC8145, or at least, acceptable.

[dev26]

Here is my implementation of control software to the multimeter: http://www.26th.net/public/projects/vc8145/

[Dave92F1]

Here is my implementation of control software to the multimeter: http://www.26th.net/public/projects/vc8145/

It works great! Thank you!!! It runs fine on Win7 x64.

My only request is re the timestamp format in the .CSV file - if you formatted it YYYY-MM-DD instead of DD-MM-YYYY, then the timestamps would sort properly (in a spreadsheet) when a run goes thru a end-of-month or end-of-year boundary.

(See http://nerdfever.com/?p=1863 for more details.)

[pascal_sweden]

How come some suppliers sell it for over 340 EUR?

http://www.benl.ebay.be/itm/VICHY-VC8145-4-5-inch-LCD-7-8-digit-Auto-ranging-Bench-top-Digital-Multimeter-/301614859290?pt=LH_DefaultDomain_101&hash=item4639a5841a

Is it the same model?

The average price seems to be around 150 EUR, so I don't understand the big price difference.

[k2teknik]

My only request is re the timestamp format in the .CSV file - if you formatted it YYYY-MM-DD instead of DD-MM-YYYY, then the timestamps would sort properly (in a spreadsheet) when a run goes thru a end-of-month or end-of-year boundary.

These things can be sorted out when you import the csv file, no reason to use any specific date format (as long as you know the format your self).
When importing into Excel you just choose that this column is a date and then what format it is, and Excel convert the date to an Excel date format.

[k2teknik]

How come some suppliers sell it for over 340 EUR?

They call it "Making money", you may ask "Why do some people pay this amount of money when the can buy the same unit at a lower price somewhere else?".

Is it the same model?

Yes.

The average price seems to be around 150 EUR, so I don't understand the big price difference.

I paid 125 USD for my instrument all included, so it pays off to search before shopping.

[pascal_sweden]

Can you send the link to the 125 USD dollar deal? =)

[Dave92F1]

My only request is re the timestamp format in the .CSV file - if you formatted it YYYY-MM-DD instead of DD-MM-YYYY, then the timestamps would sort properly (in a spreadsheet) when a run goes thru a end-of-month or end-of-year boundary.

These things can be sorted out when you import the csv file

I suppose, but it's a needless extra step. ISO 8601 timestamp format (YYYY-MM-DD HH:MM:SS.FFF) sorts naturally, and is unambiguous.

Another suggestion: Since there's no way (that we know of) to recalibrate the Vici, how about adding an option for calibration offsets into the PC program:

CalibratedResult = (RawResult + CalOffset) * CalGain

It would have to be done separately for each measurement mode (V, A, ohms, etc.).

[Dave92F1]

Can you send the link to the 125 USD dollar deal? =)

Probably that was a long time ago. Best I could find was USD 150 or so. On eBay.

[k2teknik]

Probably that was a long time ago. Best I could find was USD 150 or so. On eBay.

Yes, it was a year or so ago, I used a seller from http://www.aliexpress.com/

[pascal_sweden]

Vichy VC8145 or Victor 8145? Which one to choose?

I read that build quality is better on Victor, but what about the specs?

And what about the price difference?

Does only Vichy VC8145 have RS232 interface?