CR4® - The Engineer's Place for News and Discussion®


Previous in Forum: Where to Cut  
Close
Close
Close
41 comments
Member

Join Date: Nov 2017
Posts: 7

Single Point Calibration

11/08/2017 3:38 PM

I am trying to find if there is anything written anywhere in an official document that states it is acceptable to calibrate a freezer at a single point. If I have a freezer at a fixed -20C. Can I calibrate it at that point, or do I need to bracket it by calibrating it above and below that point. This is calibrating the display on the freezer, which means the probe is fixed internally and cannot be removed. This means I would need to change the setpoint of the freezer in order to calibrate the unit. The setpoint is never changed during normal use.

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: Auckland, New Zealand
Posts: 8448
Good Answers: 350
#1

Re: Single Point Calibration

11/08/2017 4:05 PM

If I have a freezer at a fixed -20C. Can I calibrate it at that point.......The setpoint is never changed during normal use.

Sounds reasonable then (especially if you have linearity records or tables for the existing temperature probe response).

Don't forget you can also easily calibrate at room temperature (to give you a second calibration point) by turning off the freezer, opening up the door(s) and letting it stabilize at the new temperature.

__________________
jack of all trades
Register to Reply Score 1 for Good Answer
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 9551
Good Answers: 455
#2

Re: Single Point Calibration

11/08/2017 4:18 PM

You should try to find a second point to check the gain. One "unit" could be 0.1 or 10 degrees.

__________________
"Love justice, you who rule the world" - Dante Alighieri
Register to Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 19205
Good Answers: 1125
#3

Re: Single Point Calibration

11/08/2017 4:52 PM

I don't see anything wrong with that, but I would suggest attaching an envelope with the calibration info on a piece of paper inside and date....

Calibrated by:

on date:

Accurate at -10 C:

Calibration methodology:

Then write "calibration info" on envelope....

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply
3
Guru

Join Date: Oct 2008
Posts: 39866
Good Answers: 1586
#4
In reply to #3

Re: Single Point Calibration

11/08/2017 6:11 PM

But, the freezer runs at a constant -20°.

Question to OP:

Why would you need to "calibrate" it in the first place.

If calibration is required, there must be a reason for calibration and some document that specifies the calibration and to what standard or document the calibration is required.

Where's the criticality and who is demanding it and why?

Register to Reply Good Answer (Score 3)
Member

Join Date: Nov 2017
Posts: 7
#8
In reply to #4

Re: Single Point Calibration

11/09/2017 8:03 AM

You need to verify that -20 is -20 and not -15. They have product that has to be kept at that temperature. You can't just rely that the indication on the front of the unit is correct.

Register to Reply
Guru

Join Date: Oct 2008
Posts: 39866
Good Answers: 1586
#11
In reply to #8

Re: Single Point Calibration

11/09/2017 9:50 AM

" You can't just rely that the indication on the front of the unit is correct."

It sounds like that is exactly what you have been doing.

Besides, if -20 is good then -30 would be better.(safer)

I might refer to this as verification instead of calibration, and if you are relying on a visual indication, unless there is someone sitting in front of the indicator you might not know what the temperature is.

You need an alarm and/or a back-up compressor.

I offer this:

Calibration of temperature control and monitoring devices

Register to Reply
Guru
United States - Member - Born, raised halfway 'round .....

Join Date: May 2010
Location: Speedway.....
Posts: 1040
Good Answers: 23
#13
In reply to #8

Re: Single Point Calibration

11/09/2017 10:50 AM

Dealt with the state and DOH requirements with respect to research laboratories, the requirement is to keep and maintain a log of temperature readings of every freezer(s)... The temperature reading samples taken daily or hourly depending on the requirement as dictated by a specific laboratory applications...

The accuracy of the freezer's built-in temperature meter is the one that may need to be validated /calibrated at least twice every year...sometimes monthly or quarterly based on application criticality.....

Validation is done by comparing the built-in temperature readings using a certified industry standard temperature meter...This reference meter in turn has passed an annual testing and calibration. with an NIST traceable certification issued by a certified independent testing laboratory....

__________________
vsar
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26689
Good Answers: 700
#30
In reply to #8

Re: Single Point Calibration

11/12/2017 12:20 PM

<...You need to...> Nope. Untrue. There is no obligation here to do anything in particular.

<...They have...> Then the <...They...> will have the standard against which the calibration is to be carried out. Otherwise the <...They...> would not be able to assure product quality and the installation and its documentation would not survive more than casual scrutiny..

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26689
Good Answers: 700
#34
In reply to #8

Re: Single Point Calibration

11/12/2017 12:40 PM

<...has to...> By what obligation?

<...at that temperature...> Plus or minus what?

<...kept...>

At what location in the installation:

  • by the entrance door or
  • deep within the product stack,

for example?

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Sep 2016
Posts: 746
Good Answers: 8
#38
In reply to #4

Re: Single Point Calibration

11/14/2017 11:07 PM

Perhaps some freezers used to calibrate other freezers.--in pluto

Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 13433
Good Answers: 152
#39
In reply to #38

Re: Single Point Calibration

11/15/2017 9:00 AM

Or some tweezers could be used for calibrating other brain tweezers (not teasers).

Perhaps some freezers just need verification as most all of us in here agreed to.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru

Join Date: Oct 2014
Location: Hemet, Land of milk and honey.
Posts: 1199
Good Answers: 23
#5

Re: Single Point Calibration

11/09/2017 1:25 AM

Is this what you are referring to ? :

Register to Reply
Member

Join Date: Nov 2017
Posts: 7
#7
In reply to #5

Re: Single Point Calibration

11/09/2017 7:53 AM

Thanks, but I do not see any reference to a single point calibration in there.

Register to Reply
Power-User

Join Date: Dec 2016
Location: Baytown Tx. USA where you get your gasoline,chemicals,plastics and floods
Posts: 277
Good Answers: 6
#6

Re: Single Point Calibration

11/09/2017 6:20 AM

Its not called calibration at a single point its called routine check.

__________________
formally known as texasron (proud to be an Aggy)
Register to Reply
3
Guru
United Kingdom - Member - Not a New Member Hobbies - Musician - New Member Hobbies - Fishing - New Member

Join Date: May 2006
Location: Reading, Berkshire, UK. Going under cover.
Posts: 9551
Good Answers: 455
#9

Re: Single Point Calibration

11/09/2017 9:31 AM

If the freezer has a PID controller and a cunning system to lower/hold the temperature, you may keep it near the setpoint (-20C), but it must inevitably vary a little way. The range will be greater if (as is usual) it is just an on/off thermostat type controller. You should measure the temperature over a 24-hour period, an check that it does not vary outside an acceptable range.

__________________
"Love justice, you who rule the world" - Dante Alighieri
Register to Reply Good Answer (Score 3)
Member

Join Date: Nov 2017
Posts: 7
#10
In reply to #9

Re: Single Point Calibration

11/09/2017 9:38 AM

That is part of validation. The validation checks to see if the temperature can be maintained over a period of time. Calibration verifies that the reading at a single point in time is accurate.

Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26689
Good Answers: 700
#32
In reply to #10

Re: Single Point Calibration

11/12/2017 12:29 PM

How is it done at present, then?

Or is the facility shipping uncontrolled product at present? If so, then how long can it get away with this state of affairs?

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Jul 2012
Location: Madison, WI.
Posts: 1034
Good Answers: 45
#12

Re: Single Point Calibration

11/09/2017 10:39 AM

First, a unit must be "calibrateable" to be calibrated. It sounds as if this is not one of those.

Most critical equipment requires a calibration verification by a certified organization or individual on a yearly basis. This is simply a "certified" measuring device placed in the unit and verifying that it is indeed within the stated specification.

This is usually coupled with an in house weekly, daily, hourly, per run, verification of the units function. Simply placing a testing device such as a recording thermoprobe in the freezer for a specified amount of time and recording the results. If in spec. Ya! if not, corrective action is needed per your "out of Spec" procedures.

An actual calibration of a piece of equipment is different than the calibration of a measuring device. Equipment is something more involved and usually includes two set points to establish the acceptable range. This term "acceptable range" is your stated, validated, controlled and documented, requirement per SOP, GMP, GLP, etc.

In the case of stand alone, laboratory freezers, they will come with this validation information and if you are buying at the Pharma level ($$$) a complete, NIST documented calibration. The company will usually offer calibration services as an extra cost item.

Calibration. This is the actual, physical act of changing the sensors, logic, or control range of a device to keep it within the previously mentioned, documented, specification. This is required by FDA, USDA, you name it, regulation.

You can "establish" any range you wish for a piece of equipment as long as you can document that the range is achievable, achievable consistently, repeatable by any testing organization, documentable, and meets your industries standards for the purpose or process. if there are no industry standards then it is up to your QC/QA dept. to establish this standard.

So, step one, establish the range that is acceptable for the unit. (Caution, do not set this too tight or you will be sorry)

Step two, remove all product from unit and place several certified thermoprobes with a valid calibration certificates in various locations in the unit and allow it to run undisturbed for 24 hours. Check the recorded temperature for the test period and see if the unit is capable of holding the temperature within your expected range.

Step Three, document, document, document, As long as your unit is routinely checked and within this set range it is considered good. That is all you can do if your unit is a "factory set unit".

There is a whole other level that I won't get into here if you are working with temperature critical materials. Then you need to determine Temperature rise rates, Open condition times, recovery periods, entries per hour/shift/day. A whole world of details that in a pharma product environment are required.

__________________
Knowing is the end result of learning, not believing.
Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18938
Good Answers: 335
#14

Re: Single Point Calibration

11/09/2017 10:53 AM

To calibrate it, you normally would have a master gauge that is certified, and use that for calibration.

Of course if there air movement within the freezer itself, one can 'assume?' that is the temperature through out the freezer,... If the required temperature is -20 with no air movement and if there isn't air movement, I would calibrate it by the thermostat.

With no air movement depending how tall your freezer is, and product movement in and out of the freezer, the temperature may be stratified.

And if your thermostat does not match your master gauge, calibration is required... how, I can't answer that.

__________________
phoenix911
Register to Reply
Power-User

Join Date: Sep 2012
Location: Seattle, WA, USA
Posts: 136
Good Answers: 8
#15

Re: Single Point Calibration

11/09/2017 11:31 AM

You can have constant verification with a calibrated chart recorder. Cheap to install and operate. Charts can be hourly/daily/weekly/etc. There are electronic versions that can maintain a log for a very long time without needing to change charts. Both styles can be set up with alarms when the temperature varies from the set point.

__________________
You have to actively participate in the manifestations of your own joys and good fortunes - they are not ready made for the taking, they are available for the making.
Register to Reply Score 1 for Good Answer
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18938
Good Answers: 335
#16
In reply to #15

Re: Single Point Calibration

11/09/2017 11:41 AM

good idea, plus it would give a history of any issues.

__________________
phoenix911
Register to Reply
Power-User

Join Date: Jul 2010
Posts: 126
Good Answers: 18
#17

Re: Single Point Calibration

11/09/2017 12:47 PM

I have seen single point cals done on freezers and refrigerators used for materials in pharmaceuticals. I'm not sure single point cals would pass an audit.

The screen shot from the FDA's Office of Regulatory Affairs (ORA) shows that single point cals are acceptable for specific instruments: working and reference hydrometers, but freezers and refrigerators have a different requirement.

The entire document is at
https://www.fda.gov/downloads/ScienceResearch/FieldScience/LaboratoryManual/UCM092154.pdf

Register to Reply
Member

Join Date: Nov 2017
Posts: 7
#18

Re: Single Point Calibration

11/09/2017 12:58 PM

Thanks for the input guys. Let me give you a little more history. I have been a metrologist for over 30 years. I know how to calibrate. As for any external devices, that will not work. They have the unit hooked up to the building maintenance system. That gives them 24 hour coverage and alarms in case it goes out of specifications. The probes are not removable without some serious work. The whole question here is simple single point calibration and is it acceptable.

Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 13433
Good Answers: 152
#19
In reply to #18

Re: Single Point Calibration

11/09/2017 1:17 PM

Single point verification of freezer system:

(1) toss in at least two temperature loggers and record a minimum of 24-hours for two separated locations inside the freezers.

(2) introduce a temperature transmitter, that you have already calibrated accurately to a NIST standard thermometer over the range of perhaps -25 to -15 °C. The error of your secondary standard transmitter must be within the limits acceptable to your freezer calibration, i.e., if freezer must hold ±2 °C, then 0.5 °C accuracy of your testing equipment is deemed suitable to 4 standard deviations (right?).

If the logged data range and other statistics show the range is being met by the freezer, then all you need look further to is any offset between freezer display and the secondary standard transmitter. I would locate the secondary standard transmitter probe as near as practical to the internal temperature probe of the freezer.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Power-User

Join Date: Sep 2012
Location: Seattle, WA, USA
Posts: 136
Good Answers: 8
#20
In reply to #18

Re: Single Point Calibration

11/09/2017 1:36 PM

Anything is acceptable if you write the procedure correctly. The old adage of write down what you do and do what you write down carries a long way with auditors.

Write your own procedure for your equipment. Be as specific as possible. Devise a checklist for your calibration (I would call it a verification) that documents each step. Carefully file them away.

In the event an auditor does not like what you are doing it is up to them to cite the spec to which you are not adherent. Then you have something to work with.

The short version of this plan is Baffle them with BS. ;)

__________________
You have to actively participate in the manifestations of your own joys and good fortunes - they are not ready made for the taking, they are available for the making.
Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 13433
Good Answers: 152
#22
In reply to #20

Re: Single Point Calibration

11/09/2017 2:29 PM

...or dazzle them with brilliance!!!

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru
New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: Auckland, New Zealand
Posts: 8448
Good Answers: 350
#21
In reply to #18

Re: Single Point Calibration

11/09/2017 1:38 PM

I don't see why not. This is a storage freezer so I wouldn't expect the temperature to be cycling all over the place in normal operation with the door closed, nor would I expect the near constant stabilized temperature of the freezer to be warmer unless there was a problem with the freezer seal, etc.

If the freezer stabilizes at -20 deg C and you need it to be under -15 deg C and your measuring and calibrated at -20 deg C then you should be fine. If the freezer fails in some way (eg-door seal, compressor failure, etc) then the temperature should gradually rise triggering an alarm since this is monitored. A 1 deg C (for example) measurement error is unimportant in this application.

If this is a very critical application you may need to consider adding an additional removable temperature probe suitably calibrated, either permanently fixed in position or used to perform the calibration on the existing temperature probe.

__________________
jack of all trades
Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 13433
Good Answers: 152
#23
In reply to #21

Re: Single Point Calibration

11/09/2017 2:31 PM

be very careful if and when making a new perforation for the new temperature sensor well. You need to at least be able to prove to yourself, the additional BTU leakage in will not perturb control out of normal.

That is what the little "disposable" temperature loggers are for.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru
New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: Auckland, New Zealand
Posts: 8448
Good Answers: 350
#24
In reply to #23

Re: Single Point Calibration

11/09/2017 3:59 PM

I wasn't thinking of going to the trouble of a well for a freezer application. Obviously sealing when passing through the walls is of importance.

__________________
jack of all trades
Register to Reply
Member

Join Date: Nov 2017
Posts: 7
#25

Re: Single Point Calibration

11/09/2017 4:06 PM

We are already monitoring with a second probe that is attached to the building maintenance system. The question is not how to calibrate. I know how to do that. The question is if there are any regulations that allow it at a single point. I am trying to rewrite our procedure, but our QA will not allow me to go to a single point unless I can prove it is acceptable to calibrate at a single point.

Register to Reply
Power-User

Join Date: Sep 2012
Location: Seattle, WA, USA
Posts: 136
Good Answers: 8
#26
In reply to #25

Re: Single Point Calibration

11/09/2017 4:32 PM

Ask them to prove it is not acceptable . . .

Actually, change the language. As has been said several times, you are not calibrating this system, you are merely verifying that the instrument reading is correct. You can only do that at a single point . . .

__________________
You have to actively participate in the manifestations of your own joys and good fortunes - they are not ready made for the taking, they are available for the making.
Register to Reply Score 1 for Good Answer
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 13433
Good Answers: 152
#28
In reply to #26

Re: Single Point Calibration

11/09/2017 4:51 PM

Verification testing can be as elaborate or not, but one it is, it is always one thing.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 13433
Good Answers: 152
#27
In reply to #25

Re: Single Point Calibration

11/09/2017 4:41 PM

depends on device type, if it is resistance type device, and not voltage producing, IMHO, the characteristics of the device will be homogeneous for the device type, with offset as the only necessary calibration - single point.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26689
Good Answers: 700
#33
In reply to #25

Re: Single Point Calibration

11/12/2017 12:36 PM
  • <...We...>
  • <...I...me...>
  • <...our...>

It sounds as though there is a lot of defining to do, including the <...acceptable...> criteria.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 19977
Good Answers: 749
#29

Re: Single Point Calibration

11/11/2017 5:45 PM

For this situation, single-point calibration probably should be considered adequate. But that doesn't mean that everyone will consider it adequate. For instance, overactive customers or bureaucrats might require more, whether or not reasonable.

If the sensor is expected to be accurate over a wide temperature range, then zero and span would be required. But for a narrow range, no normal sensor will drift much, if single-point calibrated at the principal temperature of interest.

__________________
In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
2
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 13433
Good Answers: 152
#37
In reply to #29

Re: Single Point Calibration

11/14/2017 10:41 AM

Again, it depends on the device. If the device is reliant upon an intrinsic elemental property (such as is the resistivity of a platinum wire), then the only "calibration" required is the offset value that compensates for any error in length and cross-section of the wire as installed.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply Good Answer (Score 2)
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26689
Good Answers: 700
#31

Re: Single Point Calibration

11/12/2017 12:24 PM

<...official document...> What does that mean? What is an un<...official document...>? Aren't all documents <...official...>? Which office, in particular?

This thread currently scores very highly on the <...official...> gobbledeygook scale.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Oct 2014
Location: Hemet, Land of milk and honey.
Posts: 1199
Good Answers: 23
#40
In reply to #31

Re: Single Point Calibration

11/15/2017 7:18 PM

When you write a love letter and try to sneak it to your intended it is an unofficial document

When the teacher intercepts it and reads it in front of class, then it becomes an official document.

Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 13433
Good Answers: 152
#41
In reply to #40

Re: Single Point Calibration

11/16/2017 12:10 PM

It is still considered bad form to get caught.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Member

Join Date: Nov 2017
Posts: 7
#35

Re: Single Point Calibration

11/13/2017 7:38 AM

This would be a calibration, not a verification. Although in this case there is little to no difference other than the fact that the units need to be calibrated on a regular basis according to internal documents. As for the word "official" that means from an entity that is official. They will not accept a procedure from another company, but would accept something from a USP or IEC or similar.

Register to Reply Score 1 for Off Topic
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26689
Good Answers: 700
#36
In reply to #35

Re: Single Point Calibration

11/13/2017 1:55 PM

And the TLAs mean what, please?

<...They...>?

<...an entity that is official...> What [TF] does that mean?

This thread is still in the realm of la-la land...

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Register to Reply 41 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Bud (1); gutmonarch (1); jack of all trades (3); James Stewart (8); JohnDG (2); Krusemark (6); lyn (2); Mike W (3); phoenix911 (2); PWSlack (6); rashavarek (1); ronc (1); SolarEagle (1); tonyhemet (2); Tornado (1); vsar (1)

Previous in Forum: Where to Cut  

Advertisement