Calculating A4, B4, A8, B8 Coefficients for RTDs

Started by Hawaii596, 01-23-2008 -- 17:29:10

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Hawaii596

01-23-2008 -- 17:29:10
I'll throw this one out for any of you who do precision RTD cals.  I have a high accuracy Hart 25 ohm SPRT which I use in my Hart drywell for verifying RTD probes (such as some of the Burns Engineering units) using comparison method.  I have an end user who has to have the A4, B4, A8, B8 numbers (as well as RTPW) to program into his HP 34420A meter for precision uses.  I spent MEGA manhours trying to find software to do the calculations for me.  There is almost nothing out there (other than buying expensive packages).  I even spent some time on the phone with VERY helpful people at NIST (they are ALWAYS ready to try and help).  Problem was, after an hour on the phone I had a headache, as the math in those coefficients is not very intuitive.

Finally, I contacted a company who makes one of those big expensive software packages.  I explained I had no use for the big cal recall system they sold, just needed something to compute RTD coefficients.  He got with their manufacturing people and lo and behold he gave me for free a small package not normally available.  I plug in temp and resistance measured at RTPW, two negative temps (Deg C), and three positive temps (I use -25, -10, 25, 50, and 100 Deg C).  Then I specify range and what resolution I want the chart to be, and it creates an entire printout including coefficient numbers.

Just wondering if anyone has any thoughts on this one.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

OlDave

#1
01-24-2008 -- 08:22:44
We needed something that would do this sort of work a few years back. I got the Hart Scientific 9933 TableWare. I think it was about $600 or so.

It's not real flashy but it does a good job of calculating coefficients and printing tables. It covers most ranges of PRTs, thermistors, and most common types of thermocouples.

Hawaii596

#2
01-24-2008 -- 09:09:18
That gives me a (sincerely) dumb question.  I have 9933.  I also HAD a Tweener meter.  My perception about the 9933 software is that it took outputs from the Tweener meter (or similar super-thermometer meter from Hart (Fluke)) and generated the coefficients.  I use a Hart 5699 super SPRT (sent to Hart annually).  But I must use my Golden HP 3458A to read resistance values and convert to temp (I made a spreadsheet to convert).

Problem is, at least as far as I can tell, I am not able to make the 9933 software generate coefficients using my current setup (HP 3458A with Hart 5699, read Res, conv. to temp).  I still have the 9933 software, but have been unable to use it.

However, this little executable file a temp OEM GAVE me is really nice (and simple). 

Back to my original question....  I have 9933 software from Hart, but can't make it work (unless someone out there knows how to make it work with HP 3458A).  I found on the internet a cal recall database custom configured for labs who do temp cals (recall database including automatically taking data on RTD cals and computing coefficients (price about $3K).  I looked high and low but found nothing.  There were a few freeware packages out there, but none of them did what I needed.

My users have a secondary type Burns 12001A probe with an OMEGA PRP-1 label on it, used with HP 34420A (I love that meter).  To make it work for them, they need coefficients.  This little free package given to me works great.  If anyone wants it, contact me and I'll email it.  I can't post a link as it isn't openly available.  I'd actually like to send to someone who could try it out to see what you think.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

OlDave

#3
01-24-2008 -- 09:46:30
We don't use the 9933 in any type of automated configuration. I just input the temperature applied and the resistance read into the program, press the calculate button (or whatever its labeled) and get the coefficients out and print a table if needed. It's been awhile since I had to use it so I'm pretty rusty with its operation.

We have version 2.3.0.2 of the 9933 TableWare. Are we sure we are talking about the same program? I just looked at mine and it doesn't even have any interface capabilities, it is all manual inputs.

flew-da-coup

#4
01-24-2008 -- 10:59:33
Quote from: Hawaii596 on 01-24-2008 -- 09:09:18
That gives me a (sincerely) dumb question.  I have 9933.  I also HAD a Tweener meter.  My perception about the 9933 software is that it took outputs from the Tweener meter (or similar super-thermometer meter from Hart (Fluke)) and generated the coefficients.  I use a Hart 5699 super SPRT (sent to Hart annually).  But I must use my Golden HP 3458A to read resistance values and convert to temp (I made a spreadsheet to convert).

Problem is, at least as far as I can tell, I am not able to make the 9933 software generate coefficients using my current setup (HP 3458A with Hart 5699, read Res, conv. to temp).  I still have the 9933 software, but have been unable to use it.

However, this little executable file a temp OEM GAVE me is really nice (and simple). 

Back to my original question....  I have 9933 software from Hart, but can't make it work (unless someone out there knows how to make it work with HP 3458A).  I found on the internet a cal recall database custom configured for labs who do temp cals (recall database including automatically taking data on RTD cals and computing coefficients (price about $3K).  I looked high and low but found nothing.  There were a few freeware packages out there, but none of them did what I needed.

My users have a secondary type Burns 12001A probe with an OMEGA PRP-1 label on it, used with HP 34420A (I love that meter).  To make it work for them, they need coefficients.  This little free package given to me works great.  If anyone wants it, contact me and I'll email it.  I can't post a link as it isn't openly available.  I'd actually like to send to someone who could try it out to see what you think.

Yeah, you can manually plug your numbers into 9933 TableWare. It is the only software I have ever used when doing SPRT and PRT/RTD cals.
You shall do no injustice in judgment, in measurement of length, weight, or volume.Leviticus 19:35

Hawaii596

#6
03-13-2014 -- 09:24:14
Wow.  That post is so old (how old is it) that I am no longer with that job and don't have any of the stuff I had when I wrote the posting.  I now have the Calcoeff2.exe software.

It was given to me by some company in NJ (whose name I can't recall) that makes or made a cal database especially for companies who use a lot of RTD's.  It had built in coefficient calculation software, of which the person very graciously provided my a freeware copy.  He didn't give me permission to distribute, so I won't put it on any website.  I just did a fresh google search and the name doesn't even come up at all.  I have a person requesting it via personal message right now.  I have put a copy in my dropbox[dot]com folder.  If anyone else wants a copy, send me a personal message with an email address and I'll send a link where you can download it from.
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

WalesMetrology

#7
03-13-2014 -- 11:18:07
I have spent many hours looking for software to do this thank you. I want to use it in order to evaluate a spread sheet I am working on. CVD coefficients and ITS90.

Hawaii596

#8
03-13-2014 -- 11:36:33
I don't remember particulars about CVD.  This is an ITS-90 calculator.  I guess I don't exactly understand the exact difference in CVD.  Is it still a 0.00385 Calculator? I was just looking in Wikipedia, and it sounds like CVD predated IPTS68, and was replaced by it.  It was then replaced by ITS-90.  I recently certified some PT100 RTD's for a customer whose specs were IEC751, which is basically 100 Ohm 0.00385 specs, with tolerance limits rather than an actual interpolation curve.  One of them didn't meet IEC751 specs, so I programmed in ITS-90 specs (which rather than rely on tolerance limits of a nominal probe, replaced them with actual curve for that probe, with RTPW offset value).
"I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind."
Lord Kelvin (1824-1907)
from lecture to the Institute of Civil Engineers, 3 May 1883

RCabual

#9
11-30-2015 -- 06:41:33
Hi,

I know this is an old thread but hopefully you still have a copy of that software. I recently needed and still cant find a freeware on the web. Appreciate if you could share it to me. Thank you.

OlDave

#10
11-30-2015 -- 07:03:58
Check out Isotech's website. They have some free calculators for download that may be suitable for your needs.

http://www.isotech.co.uk/downloads

RCabual

#11
11-30-2015 -- 08:07:43
Thanks. I have checked and need to purchase licenses.
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