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Thermocouple Accuracy

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mikepienaar09(at)gmail.co
Guest

Posted: Sat Apr 03, 2021 2:59 pm Post subject: Thermocouple Accuracy

I put my CHT sensors into boiling water at sea level and got a reading of 200 deg F and got 22 deg F with them in ice water. Is this close enough?

I am using a MGL EFIS unit

All 4 sensors provide the same reading plus or minus 1 or 2 degrees

Sensors are K type attached to a copper washer that fits under the spark plug 

 

Thanks

 

Mike

Kellym

Joined: 10 Jan 2006
Posts: 1700
Location: Sun Lakes AZ

Posted: Sat Apr 03, 2021 3:33 pm Post subject: Thermocouple Accuracy

unless you put a lot of salt in the water for the freezing part, that 

reading should be very close to 32 degrees. The boiling temp is fine, 

takes some effort to get the water above 200.



On 4/3/2021 3:58 PM, mikepienaar09(at)gmail.com wrote:

 	  Quote: 	
		   I put my CHT sensors into boiling water at sea level and got a reading 

 of 200 deg F and got 22 deg F with them in ice water. Is this close enough?

 

 I am using a MGL EFIS unit

 

 All 4 sensors provide the same reading plus or minus 1 or 2 degrees

 

 Sensors are K type attached to a copper washer that fits under the spark 

 plug

 

 Thanks

 

 Mike

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

alec(at)alecmyers.com
Guest

Posted: Sat Apr 03, 2021 3:49 pm Post subject: Thermocouple Accuracy

Whereâ€™s the other junction?



Sent from my iPhone



 	  Quote: 	
		  On Apr 3, 2021, at 7:00 PM, mikepienaar09(at)gmail.com wrote:



ï»¿  <![endif]-->   <![endif]-->

I put my CHT sensors into boiling water at sea level and got a reading of 200 deg F and got 22 deg F with them in ice water. Is this close enough?

I am using a MGL EFIS unit

All 4 sensors provide the same reading plus or minus 1 or 2 degrees

Sensors are K type attached to a copper washer that fits under the spark plug 

 

Thanks

 

Mike

kjashton(at)vnet.net
Guest

Posted: Sat Apr 03, 2021 3:53 pm Post subject: Thermocouple Accuracy

Whatâ€™s your elevation?     https://www.engineeringtoolbox.com/boiling-points-water-altitude-d_1344.html

-Kent



 	  Quote: 	
		  On Apr 3, 2021, at 7:11 PM, mikepienaar09(at)gmail.com wrote:



ï»¿  <![endif]-->   <![endif]-->

I put my CHT sensors into boiling water at sea level and got a reading of 200 deg F and got 22 deg F with them in ice water. Is this close enough?

I am using a MGL EFIS unit

All 4 sensors provide the same reading plus or minus 1 or 2 degrees

Sensors are K type attached to a copper washer that fits under the spark plug 

 

Thanks

 

Mike

mikepienaar09(at)gmail.co
Guest

Posted: Sat Apr 03, 2021 9:46 pm Post subject: Thermocouple Accuracy

Elevation is sea level



Sent from my iPhone



 	  Quote: 	
		  On Apr 3, 2021, at 4:51 PM, Kent or Jackie Ashton <kjashton(at)vnet.net> wrote:



ï»¿Whatâ€™s your elevation?     https://www.engineeringtoolbox.com/boiling-points-water-altitude-d_1344.html

-Kent



 	  Quote: 	
		  On Apr 3, 2021, at 7:11 PM, mikepienaar09(at)gmail.com wrote:



ï»¿  <![endif]-->   <![endif]-->

I put my CHT sensors into boiling water at sea level and got a reading of 200 deg F and got 22 deg F with them in ice water. Is this close enough?

I am using a MGL EFIS unit

All 4 sensors provide the same reading plus or minus 1 or 2 degrees

Sensors are K type attached to a copper washer that fits under the spark plug 

 

Thanks

 

Mike

mikepienaar09(at)gmail.co
Guest

Posted: Sat Apr 03, 2021 9:46 pm Post subject: Thermocouple Accuracy

Normal water



Sent from my iPhone



 	  Quote: 	
		   On Apr 3, 2021, at 4:48 PM, Kelly McMullen <kellym(at)aviating.com> wrote:

 

 ï»¿

 

 unless you put a lot of salt in the water for the freezing part, that reading should be very close to 32 degrees. The boiling temp is fine, takes some effort to get the water above 200.

 

> On 4/3/2021 3:58 PM, mikepienaar09(at)gmail.com wrote:

> I put my CHT sensors into boiling water at sea level and got a reading of 200 deg F and got 22 deg F with them in ice water. Is this close enough?

> I am using a MGL EFIS unit

> All 4 sensors provide the same reading plus or minus 1 or 2 degrees

> Sensors are K type attached to a copper washer that fits under the spark plug

> Thanks

> Mike

mikepienaar09(at)gmail.co
Guest

Posted: Sat Apr 03, 2021 9:55 pm Post subject: Thermocouple Accuracy

One end of the thermocouple wire is attached to the copper ring under the plug, the other end is connected to the MGL RDAC unit that feeds signal to the EFIS. There are no joins in the wire



Sent from my iPhone



 	  Quote: 	
		  On Apr 3, 2021, at 4:53 PM, Alec <alec(at)alecmyers.com> wrote:



ï»¿Whereâ€™s the other junction?



Sent from my iPhone



 	  Quote: 	
		  On Apr 3, 2021, at 7:00 PM, mikepienaar09(at)gmail.com wrote:



ï»¿  <![endif]-->   <![endif]-->

I put my CHT sensors into boiling water at sea level and got a reading of 200 deg F and got 22 deg F with them in ice water. Is this close enough?

I am using a MGL EFIS unit

All 4 sensors provide the same reading plus or minus 1 or 2 degrees

Sensors are K type attached to a copper washer that fits under the spark plug 

 

Thanks

 

Mike

alec(at)alecmyers.com
Guest

Posted: Sun Apr 04, 2021 3:04 am Post subject: Thermocouple Accuracy

Well, to me, it sounds like the cold junction compensation is off by 10 degrees.



If thatâ€™s it, then itâ€™s going to read 10 degrees low at all temperatures, and youâ€™re unlikely to care.



Sent from my iPhone



 	  Quote: 	
		  On Apr 4, 2021, at 1:56 AM, mike Pienaar <mikepienaar09(at)gmail.com> wrote:



ï»¿One end of the thermocouple wire is attached to the copper ring under the plug, the other end is connected to the MGL RDAC unit that feeds signal to the EFIS. There are no joins in the wire



Sent from my iPhone



 	  Quote: 	
		  On Apr 3, 2021, at 4:53 PM, Alec <alec(at)alecmyers.com> wrote:



ï»¿Whereâ€™s the other junction?



Sent from my iPhone



 	  Quote: 	
		  On Apr 3, 2021, at 7:00 PM, mikepienaar09(at)gmail.com wrote:



ï»¿  <![endif]-->   <![endif]-->

I put my CHT sensors into boiling water at sea level and got a reading of 200 deg F and got 22 deg F with them in ice water. Is this close enough?

I am using a MGL EFIS unit

All 4 sensors provide the same reading plus or minus 1 or 2 degrees

Sensors are K type attached to a copper washer that fits under the spark plug 

 

Thanks

 

Mike

dj_theis

Joined: 28 Aug 2017
Posts: 56
Location: Minnesota

Posted: Sun Apr 04, 2021 5:22 am Post subject: Re: Thermocouple Accuracy

Mike,



Maybe this link will offer a few ideas to help trouble shoot.



https://blog.wika.us/products/temperature-products/six-common-causes-thermocouple-temperature-measurement-errors/



The ice bath error is outside of what should be expected. Do you have a separate measurement method? Fluke makes a model â€œ52â€ for temperature measurement.  Iâ€™ve not looked into any of the low cost options from EBay  but it might be something to consider as a second method to verify.



Obviously you donâ€™t need the device to report accurate freezing temp but it might be indicative of a larger problem.



I would suspect a wiring mistake or an error in the MGL.



Dan Theis

_________________
Dan Theis
Scratch building Sonex #1362
Still working on the Revmaster Alternator improvement

Ceengland

Joined: 11 Oct 2020
Posts: 379
Location: MS

Posted: Sun Apr 04, 2021 6:35 am Post subject: Thermocouple Accuracy

On 4/3/2021 5:58 PM,       mikepienaar09(at)gmail.com (mikepienaar09(at)gmail.com) wrote:

     

      	  Quote: 	
		                       (at)font-face 	{font-family:"Cambria Math"; 	panose-1:2 4 5 3 5 4 6 3 2 4;}(at)font-face 	{font-family:Calibri; 	panose-1:2 15 5 2 2 2 4 3 2 4;}p.MsoNormal, li.MsoNormal, div.MsoNormal 	{margin:0cm; 	font-size:11.0pt; 	font-family:"Calibri",sans-serif; 	mso-fareast-language:EN-US;}span.EmailStyle17 	{mso-style-type:personal-compose; 	font-family:"Calibri",sans-serif; 	color:windowtext;}.MsoChpDefault 	{mso-style-type:export-only; 	font-family:"Calibri",sans-serif; 	mso-fareast-language:EN-US;}div.WordSection1 	{page:WordSection1;}  <![endif]-->   <![endif]-->                

I put my CHT sensors into boiling water at           sea level and got a reading of 200 deg F and got 22 deg F with           them in ice water. Is this close enough?         

I am using a MGL EFIS unit         

All 4 sensors provide the same reading plus           or minus 1 or 2 degrees         

Sensors are K type attached to a copper           washer that fits under the spark plug          

          

Thanks         

          

Mike       

     	
     Is the MGL monitor software-configurable for type J & type K     probes? If so, does config match type?

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_________________
Charlie

Kellym

Joined: 10 Jan 2006
Posts: 1700
Location: Sun Lakes AZ

Posted: Sun Apr 04, 2021 7:24 am Post subject: Thermocouple Accuracy

Well, then you know your thermcouple is off by 10 degrees at the low end.



On 4/3/2021 10:46 PM, mike Pienaar wrote:

 	  Quote: 	
		   

 

 Normal water

 

 Sent from my iPhone

 

> On Apr 3, 2021, at 4:48 PM, Kelly McMullen <kellym(at)aviating.com> wrote:

>

> ï»¿

>

> unless you put a lot of salt in the water for the freezing part, that reading should be very close to 32 degrees. The boiling temp is fine, takes some effort to get the water above 200.

>

>> On 4/3/2021 3:58 PM, mikepienaar09(at)gmail.com wrote:

>> I put my CHT sensors into boiling water at sea level and got a reading of 200 deg F and got 22 deg F with them in ice water. Is this close enough?

>> I am using a MGL EFIS unit

>> All 4 sensors provide the same reading plus or minus 1 or 2 degrees

>> Sensors are K type attached to a copper washer that fits under the spark plug

>> Thanks

>> Mike

>

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

mikepienaar09(at)gmail.co
Guest

Posted: Sun Apr 04, 2021 7:31 am Post subject: Thermocouple Accuracy

Yes I have configured for â€œKâ€ type thermocoupleForgot to say that MGL says results are within spec but did not say what the acceptable range is



Sent from my iPhone



 	  Quote: 	
		  On Apr 4, 2021, at 7:42 AM, Charlie England <ceengland7(at)gmail.com> wrote:



ï»¿                   On 4/3/2021 5:58 PM,       mikepienaar09(at)gmail.com (mikepienaar09(at)gmail.com) wrote:

     

      	  Quote: 	
		                       (at)font-face 	{font-family:"Cambria Math"; 	panose-1:2 4 5 3 5 4 6 3 2 4;}(at)font-face 	{font-family:Calibri; 	panose-1:2 15 5 2 2 2 4 3 2 4;}p.MsoNormal, li.MsoNormal, div.MsoNormal 	{margin:0cm; 	font-size:11.0pt; 	font-family:"Calibri",sans-serif; 	mso-fareast-language:EN-US;}span.EmailStyle17 	{mso-style-type:personal-compose; 	font-family:"Calibri",sans-serif; 	color:windowtext;}.MsoChpDefault 	{mso-style-type:export-only; 	font-family:"Calibri",sans-serif; 	mso-fareast-language:EN-US;}div.WordSection1 	{page:WordSection1;}  <![endif]-->   <![endif]-->                

I put my CHT sensors into boiling water at           sea level and got a reading of 200 deg F and got 22 deg F with           them in ice water. Is this close enough?         

I am using a MGL EFIS unit         

All 4 sensors provide the same reading plus           or minus 1 or 2 degrees         

Sensors are K type attached to a copper           washer that fits under the spark plug          

          

Thanks         

          

Mike       

     	
     Is the MGL monitor software-configurable for type J & type K     probes? If so, does config match type?

   

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Ceengland

Joined: 11 Oct 2020
Posts: 379
Location: MS

Posted: Sun Apr 04, 2021 12:57 pm Post subject: Thermocouple Accuracy

Just for grins, try setting it up for type J & see what happens. MGL may

well use type K for CHT, but generic CHT probes are usually type J.



On Sun, Apr 4, 2021 at 10:37 AM mike Pienaar <mikepienaar09(at)gmail.com>

wrote:



[quote] Yes I have configured for â€œKâ€ type thermocouple

 Forgot to say that MGL says results are within spec but did not say what

 the acceptable range is



 Sent from my iPhone



 On Apr 4, 2021, at 7:42 AM, Charlie England <ceengland7(at)gmail.com> wrote:



 ï»¿

 On 4/3/2021 5:58 PM, mikepienaar09(at)gmail.com wrote:



 I put my CHT sensors into boiling water at sea level and got a reading of

 200 deg F and got 22 deg F with them in ice water. Is this close enough?



 I am using a MGL EFIS unit



 All 4 sensors provide the same reading plus or minus 1 or 2 degrees



 Sensors are K type attached to a copper washer that fits under the spark

 plug



 Thanks



 Mike



 Is the MGL monitor software-configurable for type J & type K probes? If

 so, does config match type?

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_________________
Charlie

dj_theis

Joined: 28 Aug 2017
Posts: 56
Location: Minnesota

Posted: Thu Apr 08, 2021 4:57 am Post subject: Re: Thermocouple Accuracy

I like Charlieâ€™s suggestion of checking other calibration configurations on the MGL.  



To respond to Mikeâ€™s first question, â€œis 10 degrees close enough?â€

It probably depends on your expectations and willingness to accommodate a known error in your Temperatures.   Knowing the source of the error and insuring it remains constant is probably as important.



Personally, I would not accept it as â€œgood enough.â€



A second method of measurement is often useful.  I purchased a very low cost unit to compare to my trusted Fluke.



The attached photo shows a 1 degree difference in one photo but it is due to elevating the TC bulb at different heights from the floor.  



I swapped the 4 TC probes I had between the two meters in various combinations and could not see any difference in response or value reported between the Fluke and the low cost alternative.  Two of the probes came with the meter and two were from Omegs.



My conclusion on first sampling of the low cost TC meter is that it is quite adequate.  No telling how well it will perform a year from now, for sure.  Only time will tell.



Dan Theis



https://www.amazon.com/dp/B071V7T6TZ?psc=1&smid=A1L1WUWYKZGTBQ&ref_=chk_typ_imgToDp

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_________________
Dan Theis
Scratch building Sonex #1362
Still working on the Revmaster Alternator improvement

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