PRT Readout or 7.5 Dmm - Page 1
Forum section: electronics / general

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: December 31, 2020, 01:14:06 am
content: Looking to buy one of the following:Fluke 1502Fluke 1523Fluke 15247.5 dmm w high accuracy 100 ohm resistance.Looking to get my MU with a Fluke 5615 down to around 0.05C if possible.I hear someone one the forum has a prt readout as well, which I would entertain.

author: bob91343
author_rank: Super Contributor
timestamp: December 31, 2020, 05:51:52 am
content: If you wouldn't use acronyms you might get more answers.I will take a guess at what you are looking for and suggest an HP 3458A.

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: December 31, 2020, 09:52:11 am
content: I specifically used model numbers, and I have an 8.5 digit dmm with a Keithley 2002 - so I was pretty specific.

author: bob91343
author_rank: Super Contributor
timestamp: December 31, 2020, 07:49:57 pm
content: What is prt?

author: bdunham7
author_rank: Super Contributor
timestamp: December 31, 2020, 09:24:04 pm
content: Quote from: bob91343 on December 31, 2020, 07:49:57 pmhttps://us.flukecal.com/products/temperature-calibration/probes-sensors/platinum-resistance-thermometers-prts/5615-secondaryThis is in the buy/sell forum, so I'm sure the OP didn't intend this as a general-purpose discussion.OP: I think you've identified the likely candidates. The only DMM I know with those levels of accuracy for a PRT would be the Fluke 8588A. The Keithley DMM7510 and Fluke 8846A fall a bit short of your goal.

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: December 31, 2020, 11:00:33 pm
content: I more or less was looking specifically for the Fluke models listed above if anyone had them (or something similar from iso-tech for example) to use as a readout for resistance thermometers. Thanks.

author: bob91343
author_rank: Super Contributor
timestamp: January 01, 2021, 12:18:32 am
content: Thank you. Now I know PRT means platinum resistance thermometer. I apologize for my ignorance but asking the group seemed to be the proper way to learn.

author: maat
author_rank: Regular Contributor
timestamp: January 01, 2021, 07:46:23 am
content: I do have a Fluke 1524, and said PRT and I also have a 2389-J Adapter. The adapter convert from the INFOCON connector to 4-wire banana plugs.I not know, whether you want to get absolute readings, because that would require frequent (and fairly expensive) calibrations or are after relative changes and therefore need resolution.I have used the PT100 both with the F1524 and several DMMs like a DMM6500 or 34470A and here is my experience.Fluke 1524:It is decent and does its job. The 1523/24 is not a "real" Fluke device. It was made by Hart Scientific which was bought by Fluke in 2001. The UI is mediocre and seems antiquated, with quire a few unintuitive quirks. Having said that, I do like the 1524 for being portable and having two channels. I also have a Fluke 5611T-P 10k thermistor, which I use with the 1524 and I use both sensor if I need to get a "decent" temperature reading in the lab or to run a sanity check on other devices like temperature controllers. In that regard, the INFOCON connector is nice, because it stores the calibration constants and makes switching sensors a bliss. When using it as a datalogger, you will realise, that this thing is slow as hell. The internal memory lasts for about 4 hours of logging at 1s intervals and then it takes ages to transfer the 2x 15k samples from the device using the 9600 baud serial port. When I use it for data logging, I hook it up to a computer and poll the data once per second, because I don't want to die of old age waiting. The absence of an internal battery charger limits the use as handheld logger anyway, because you need to take it apart (like a handheld DMM) to replace the 3 AA, once the batteries are empty, so when logging it will be hooked up to the wall charger, so one more cable is not much of a hassle.The resolution of the data is limited to 1 mK, which shows in plots, but is absolutely acceptable as your uncertainty is a lot larger anyway.DMM:The resolution a DMM delivers is stunning and if you want relative data for plotting this will easily get you below 0.1 mK, the point, where you will see just about anything happening in a 1 m radius around the probe. For absolute measurements a 6.5 digit DMM is about on par (about 100 ppm vs. 60 ppm), but you can alway check against a 100 ohm standard, which can be had for fairly good prices and will bring down you uncertainties well below the level of the 1524. A Fluke 8588A (as suggested) is most certainly total overkill, rather go for a DMM that has a "low power" resistance mode (100 µA vs 1 mA of exitation current), then you will also get rid of that nasty self-heating effekt, which will add about 5 mK @ 1mA current of uncertainty.Using a DMM for quick measurements at low uncertainties is not viable, because you need to look up the calibration constants of the PRT, check the DMM against the 100 ohm reference, etc, but when used in a static setup it will deliver crisper results.So all in all, I do recommend the Fluke 1523/24 if you want quick hassle free no-brain measurements. If you want to build a static setup connected to a computer, check out DMMs. If size matters the 1524 is also great, because it delivers two channels in small package. If you want more channels look at the Fluke 1586A, which is hard to beat in terms of simplicity.I hope this helps a bit. If you have any questions, fire away and I will try to help.

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: January 01, 2021, 12:54:32 pm
content: Thank you so much for this information. I have used a Hart/Fluke 1502 in the past and it was a great benchtop meter. You’ve pointed out some flaws in the 1524 that actually make it not as appealing to me - I was already concerned with the “cheap” feel they have, and having to change batteries on a data logger could be troublesome if at an in opportune moment. I am going to do a little more research on the excitation currents available per your description to see what I can find. Current meters in my stock at 6.5 or above are 34401A and 8846A also Keithley 2002. I know I can use the 2002 I just didn’t want to have it running the amount of hours I monitor temperatures (stability chambers).

author: tszaboo
author_rank: Super Contributor
timestamp: January 01, 2021, 02:06:03 pm
content: No need for 7.5 Digits. A 34465A will do probe accuracy + 0.05C on a PT100. Even better on a PT1000. Get the best PT1000 you can, and save some money.

author: CalMachine
author_rank: Frequent Contributor
timestamp: January 07, 2021, 04:16:48 am
content: I've got an Instrulab 4221B for salehttps://www.torontosurplus.com/instrulab-4221-13-15-06-4200-series-temperature-monitor-range-218c-to-660c-celcuis-its90-25-5ohm-sprt-programmable-coefficients-117v-50-to-400hz.html

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: January 07, 2021, 07:32:54 am
content: That is a nice unit and super accurate - alright for a different type of sensor than I have. Thanks for sharing, though!

author: CalMachine
author_rank: Frequent Contributor
timestamp: January 08, 2021, 04:16:48 am
content: Quote from: itsbiodiversity on January 07, 2021, 07:32:54 amWhat do you mean? Your fluke 5615 is a 100 Ohm PRT. This thermometer works with 100 Ohm PRTs

author: TiN
author_rank: Super Contributor
timestamp: January 08, 2021, 05:23:46 am
content: I have Fluke 1590 that does not get my love anymore.

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: January 08, 2021, 11:11:32 pm
content: Wowser! That is the type dreams are made of. I’ll pm you.