fluke multimeter with thermocouple

[subsearobot]

I am using a fluke 189, with a type k thermocouple, made by fluke. it appears that there is a verrrrry slow response time (close to 10 minutes). does anyone have any real world experience with these?

I have several thermocouples affixed to various lines in my HVAC system, and only 1 fluke, so I must go around and plug into each sensor. Each time I plug, I am getting this huge settling time, not to mentioin wild readings. I am onsite with a big operation, and need results fast... (as usual).

Any ideas?

 

[IRstuff]

How is the thermocouple constructed? Is it a bare thermocouple? What kind of thermal mass is there?

TTFN

FAQ731-376

 

[imok2]

You need the 80AK adapter with that meter to use the thermocouple

 

[AbbyNormal]

with some budget it is easy to implement a way of logging it.

Could try some of these , does temp/rh

http://www.onsetcomp.com/solutions/products/loggers/_loggerviewer.php5?pid=479

This one has two temp probes

http://www.onsetcomp.com/solutions/products/loggers/_loggerviewer.php5?pid=480

Need some software and an optic base to go with them.



Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[subsearobot]

I am using the 80AK adapter. that would not be causing the slow response, would it?

Does anyone know the electronics or alogrythm that the fluke is using to replace the 0 degree refrence temperature? is this normal for a fluke? the literature specifys a 500ms response for temp readings, not 10 minutes.

I may need to purchase sensor package- I am measuring the outside of 3/8" stainless piping, which is flowing our cooling fluid, so I need a small sensor probe.

please help- i am not an hvac guy- this is a bit out of my expertise.

 

[imok2]

I suspect the sensor is defective ..Is it still under warenty or call the mfg and talk to custemer service
Your Connection to Electronic Products and Components
1-800-543-4330

 

[subsearobot]

i ice-bath calibrated two sensors with good agreement between the both. is the Fluke bad? It seems operate correctly otherwise. When reading the mV output, in the ice bath, it stabilized in a minute or two to .020 mV (or was it .002?)

 

[IRstuff]

Have you tried a different thermocouple? At less than $30, it seems a bit odd that that you wouldn't just get another one as a backup:

http://sales.hammondelec.com/storef...&searchType=S&simpleSearchType=D&keyword=80bk

TTFN

FAQ731-376

 

[gepman]

I have the same equipment (Fluke 189 and 80AK). I normally do not plug in different probes. When I use my insertion probe (I forget the Fluke model number) my response time is usually less than one minute however that is with the probe already plugged into the Fluke. I did one time leave my probe in place and then returned and plugged the probe back into the Fluke 189 and experienced the same phenomena that you did. I thought at the time that it may have been the zero reference temperature circuit that they use (I had just changed from a low temperature area to a warm temperature area) but perhaps it is caused by some other "feature" of their measuring circuit electronics. I suggest that you send a support request to Fluke at

http://register.fluke.com/globalforms/uSContactUs.asp

and describe the problem. Please let me know what their reply is.

 

[subsearobot]

I spoke with an engineer at fluke. He had never heard of the problem, went to do some research and never got back to me. But, based on what he did tell me, I believe you are correct, gepman. The meter needs to stabilize its zero refrence circuit for at least an hour before taking a reading. This was not practical in my situation, but in a test I verified that with a stabil ref temp, the read-out settled in about a minute.

I also learned that a fluke has a temp accuracy of only =/- 1 C, and the probes that I had were +/- 3C. seeing as I was seeing delta T of 3 degrees, that's no good.

Bottom line- Fluke is NOT a good temperature probe!

For our system, we have gone with a system of pt100 sensors for better accuracy.

 

[gepman]

Thank you for getting back to me on the situation. Thermocouples should never be used where high accuracy is needed, both because they are easily influenced by noise and because they are not accurate. Type K is about +- 2 deg. F. It is NOT a Fluke issue but a thermocouple issue. If you use the same thermocouple probe (or calibrate each different probe) you won't have such an accuracy problem but with your situation of plugging in different probes and having a delta T of only 3 degrees then RTD's are the best choice for you ( I always use RTD's in industrial situations).

 

[yorkmangr]

My friend get the FLUKE 52II is a good thermometer and very fast,i use one my self

 

[EmeraldCoastHVACR]

I use a Fluke 52 II with bead probes -- awesome field thermometer.

Cold ambient will slow response, that's why you have to keep the unit in an insulated case when taking LT & MT refrigerant superheats.