Products > Test Equipment
Process Calibrator Reccomendations?
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Tech_Monkey:

--- Quote from: Tomorokoshi on June 15, 2023, 12:56:09 am ---1. By "test the controllers calibration" do you mean what the controller reads from the thermocouple? Its 4-20mA output? Something else? Those terms have both general definitions and very specific definitions depending on the industry they are being used in.


2. Google "process calibrator" and a few things show up. I took a quick look at the Uni-T UT725. Perhaps something like that is acceptable. Note: you get what you pay for with this kind of equipment.

However, I suspect the real problem, as you state, is how to talk to Management about this kind of thing. A few questions:

3. Is the organization financially stressed?

4. What kind of organization is it? Sales? Service? Manufacturing? Engineering? Other?

5. Is mechanical engineering the educational background of Management?

6. Is accounting the educational background of Management?

--- End quote ---

1. I just need to simulate the thermoelectic voltage of a thermocouple.  The charts are online with the correlation of voltage to temperature. (roughly -10 to 30 millivolts) So I'm looking for a certified device to simulate those voltages and ensure that the temperature shown on the display matches what the thermocouple input is.  We have some situations where our machines are having to run hotter than expected on the controls. The problem is either ground looping, or lack of noise immunity in the controllers.   I believe the issue is with the grid, management believes its the controllers so frankly I'm about to spend 5k to prove them wrong.  (there is also harmonics issues and low power factor issues involved here. this whole grid is just a mess frankly)

2 I would like the equipment we buy to be good for the long term, calibrated, certified, and able to grow with a rapidly growing company.
3 no and thats what annoys me more than anything.
4 heavily engineering reliant manufacturing.
5 lol
6.  lol x2.
TimFox:
The method I suggested is calibrated from first principles.
It may be cumbersome and labor-intensive, but apparently you can't get enough budget to purchase the faster, higher-cost, digitally controlled calibration equipment.
Perhaps your boss can hire, as a summer intern, a nephew who studied high-school physics and can read instructions to do it at an acceptable cost?
Tech_Monkey:
idk why i didnt think about fleabay. Thanks. 
RAPo:
I use The service of .
About 250 euro on Ali.
Tech_Monkey:

--- Quote from: TimFox on June 15, 2023, 01:46:13 pm ---
--- Quote from: Tech_Monkey on June 14, 2023, 11:06:39 pm ---I use a fluke 289  for all my voltage metering issues.  im not trying to test the thermocouples accuracy, i'm trying to test the controllers calibration.   I dont think I follow how your advice helps me.

--- End quote ---

Secton 4.2 of my citation shows how to calibrate a meter that measures a thermocouple voltage, using a voltage source and ice-point junction.
It is NOT a method to calibrate the thermocouple itself.
I used that procedure to calibrate a thermocouple meter without needing a variable temperature, using a measured voltage into the circuit (copper wires) and inserting the thermocouple wires into the meter.
I started with a commercial thermocouple (with appropriate connector), cutting the junction and using the two dissimilar wires in the circuit shown in section 4.2.
It's a nuisance to develop a known temperature of 1000o C on the bench, but a type J thermocouple in the circuit I cited needs 57.953 mV from the external voltage supply (measured on a normal voltmeter) to give the same results in the thermocouple meter.

I assume the expensive calibrators do essentially the same thing, although they do not use frozen distilled water for the ice-point junction.

Tables of thermocouple emfs for different metal combinations are readily available, e.g.  https://www.thermocoupleinfo.com/thermocouple-reference-tables.htm  and "Rubber Bibles" (Handbook of Chemistry and Physics, formerly published by the Chemical Rubber Company, now CRC)   https://hbcp.chemnetbase.com/faces/contents/ContentsSearch.xhtml;jsessionid=8E86BDA9072F1211BDD5A2DAF5F3F562

--- End quote ---

I understand what youre saying. But thats not really going to work for the type of tests  i need to run across a range of loads and power quality situations.   Process calibrator makes it much simpler.  I found one for 1800 i think I can get. so no worries. thanks for your input
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