7 replies to this topic

[pmf]

Hello,

Last year we installed a remote environmental temperature control system to check our refrigerated rooms and freezers. The loggers were calibrated and mounted on the walls of the fridges. This year they are due for calibration again. I was wondering what would be the most practical way to organise this. We were planning to use another calibrated device and use it to compare the temperatures of the loggers. The values that we receive though vary with more than 1C at some times as it cannot be attached exactly to the logger's probes.
What would be an acceptable deviation in this case? Or any other ideas that we can probably try?
Any help will be much appreciated.

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[Charles.C]

Hi pmf,

 

It may depend on what you mean by "exactly" but if the location of reference probe is not in close proximity to the fixed position device, it is difficult to see how you can perform a reliable calibration.

 

The typical, recommended,  max. deviation I have seen for thermometers is +/- 1degC.

[Charles.C]

addendum

 

I have no experience with dataloggers but I note from the IT that there are various options for calibrating such instruments depending on the unit and maybe its application. Some apparently even offer self-calibration (presumably an electronic check/offset) (see user manual).

 

Maybe worth contacting yr supplier/distributor to ask their advice (service?).

 

Any remote datalogger users around ?

[BrummyJim]

Hi pmf,

 

It depends if it's a monthly or annual calibration. My experience is that you should be validating that the system is accurate at either end of it's intended use range (e.g. -10 to +10 for a chiller) each month. Annually you should be checking within the range that it is also accurate.

 

From the days when I used dataloggers we would calibrate the probes and loggers separately. Both would be calibrated, but being separated, the probe or logger could be substituted to allow continuous monitoring. If your loggers can be removed and substituted, you can compare to the reference probe in a more controlled environment such as water.

[pmf]

addendum

I have no experience with dataloggers but I note from the IT that there are various options for calibrating such instruments depending on the unit and maybe its application. Some apparently even offer self-calibration (presumably an electronic check/offset) (see user manual).

Maybe worth contacting yr supplier/distributor to ask their advice (service?).

Any remote datalogger users around ?

Thank you Charles.

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[Ryan M.]

I'm not sure I understand correctly.  Do the remote loggers have probes attached to them or internal probe?

If attached probe I would set the probe and your reference standard thermometer probe into a cup of water or glycerin.  This will provide stability for both probes.  You have to wait for them to equalize, but once they do you'll have your reference point.

[Charles.C]

I'm not sure I understand correctly.  Do the remote loggers have probes attached to them or internal probe?

If attached probe I would set the probe and your reference standard thermometer probe into a cup of water or glycerin.  This will provide stability for both probes.  You have to wait for them to equalize, but once they do you'll have your reference point.

 

The OP suggests that the probe is not readily accessible.

[Ryan M.]

The OP suggests that the probe is not readily accessible.

 

Ah....well nevermind then.