Cheapest RS232 Serial DMM with LabVIEW instrument driver

[JamesDean]

Hi all,

I certainly like NI hardware products but I am looking for a very low-priced (hopefully <$100) serial driven DMM that has an available LV instrument driver. I've seen some in that price range, e.g.

http://www.amazon.com/TekPower-TP4000ZC-RS232-Interaced-Ranging-Multimeter/dp/B000OPDFLM/ref=cm_cr_p...

but they don't have the LV driver. Looking through DMM drivers on ni.com/idnet helps but there are no prices there 🙂

Any suggestions would be very helpful, thank you!

[JÞB]

What measurements, ranges and accuracy do you need-  these specs can drive the price from $89 for a usb DAQ to several thousand

[ChillyWilly]

that is a very good price for a DMM with RS232.  Even is there aren't any LV drivers included you can write a small VI to control/read it.  I'm getting one of these, thanks for the link.

[Henrik_Volkers]

Since there are no requirements to the spec 😉 .... searching for (optical) RS232 and Multimeter give me

http://www.conrad.biz/ce/de/product/123294/VOLTCRAFT-VC820-DMM/1101010

for less than 50 EUR.

I remember using something similar about 10 years ago. It took me less than 30min to write a application to log data. 

We had about 10 units , none lived longer than about 5 years... you get what you pay for 

I remember once the range dial of one unit had contact problems, opening the case and looking at the PCB made the worses soldering nightmares come true...

Quality is the moment when expectation meets reality. So even cheap stuff is of quality .. if you expect nothing 😉

[MrPao]

Could you please suggest a method to read data from this multimeter  in Labview. 

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@ChillyWilly wrote:

that is a very good price for a DMM with RS232.  Even is there aren't any LV drivers included you can write a small VI to control/read it.  I'm getting one of these, thanks for the link.

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Could you please suggest a method to read the data from this multimeter in Labview

[ChillyWilly]

I just ordered a couple of them.  Once I get them I'll spend a little bit of time and write a small program for it.  I'll post it when I have it working.

[ChillyWilly]

So I got this DMM now and I've played a bit with it in LabVIEW.  After some searching online I found this bit of info:  http://www.multimeterwarehouse.com/TP4000ZC/RS232Protocol.jpg

here is a VI that gets the comm port data into LabVIEW.  I've used a vi that I found in the forums to convert the data to a normal string. 

Now I just need to figure out how to translate the bytes in the string to the numbers.  My guess is that a couple of bytes correspond to the DMM setting (what you are measuring) and the others to the data and maybe even the range.  Anyways, I post it here in hopes that others can pitch in a bit of code and get a working VI to read these DMMs.

If this VI is broken because the sub VI I downloaded is not included, just do a quick search for the name of the sub-vi on the site and add terminals to the input and output strings. (do not re-invent the wheel).  

[ChillyWilly]

I forgot to change the default values on the vi I attached to the last post, but the link should give you an idea of what some of the values should be, but most importantly set the byte count to 14.  Check the block diagram to see how it is using the length and offsets.  

I used length of 2, but then again I'm not sure this part if even needed.

[JamesDean]

Thanks everyone for your help, and especially ChillyWilly!

I've ordered a similar DMM to the one I earlier posted and I'm going to be doing the same thing as you did as soon as it arrives. I'll keep you posted!

[colinzhang]

so cheap, it is really a good news.