[EE] CU-50 RTD resistance chart?

Post by William Couture
Or possibly [OT] -- maybe I'm searching with the correct terms, but I'm
trying to find
an resistance chart for a CU-50 RTD probe.
The best I've been able to come up with is this image, which isn't quite
https://is.alicdn.com/img/pb/747/046/531/531046747_904.jpg
Pointers to something better?
Thanks!
Bill

http://www.thermometricscorp.com/PDFs/10_ohm_copper_rtd-0.00427_in_C.PDF

Multiply numbers by 5.

OR

Loading Image...

Halve these numbers.

depending on whether it's 50R at 0 degrees C or at 25 degrees C.

There may be others based on 75F or something.

Copper RTDs are all over place in terms of the quoted resistance (and
therefore the tempco) when you get down to the last decimal place or
two, AFAIK there is no standard.

One of the main applications would be homemade with a bit of wire left over
from winding the motor, so annealing and exact composition would be
questionable.

--sp

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William Couture

2017-09-09 15:34:08 UTC

Both those charts have different thermal coefficients, and have different
"zero" scales -- the 10R is 10R at 25C, the 100R is 100R at 0C.

the 10R chart multiplied by 5.5356 is closer, but it's strange that a real
chart can't be found anywhere...

Bill

http://www.thermometricscorp.com/PDFs/10_ohm_copper_rtd-0.00427_in_C.PDF
Multiply numbers by 5.
OR
http://www.thermometricscorp.com/images/Accessories/
thermometricscorp_2129_12162627.gif
Halve these numbers.
depending on whether it's 50R at 0 degrees C or at 25 degrees C.
There may be others based on 75F or something.
Copper RTDs are all over place in terms of the quoted resistance (and
therefore the tempco) when you get down to the last decimal place or
two, AFAIK there is no standard.
One of the main applications would be homemade with a bit of wire left over
from winding the motor, so annealing and exact composition would be
questionable.
--sp
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s***@interlog.com

2017-09-09 22:41:51 UTC

Post by William Couture
Both those charts have different thermal coefficients, and have different
"zero" scales -- the 10R is 10R at 25C, the 100R is 100R at 0C.
the 10R chart multiplied by 5.5356 is closer, but it's strange that a real
chart can't be found anywhere...
Bill

They're all real- it's just that there is no international standard
for Cu RTDs that I know of. You have not mentioned why you want this-
obviously if you are buying the sensor you are going to want to go to
the manufacturer for the data. If you are trying to make a general
purpose indicator or controller.. you might want to use this (assuming
the reference temperature of 25 C is appropriate..)

http://www.pyromation.com/Downloads/Data/427_c.pdf

Again, scale the numbers appropriately (5:1 in this case). Anything that's
within a degree or two C at the extremes is probably better than the sensor
interchangeability.

Where exactly did you run into a 50 ohm copper RTD?

--sp

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William Couture

2017-09-11 17:54:53 UTC

I ran into this sensor when I bought a cheap Chinese controller -- it came
with one.

I write software for industrial process controllers professionally, and
occasionally buy
one of the cheap controllers I see around (aliexpress, ebay) just to see
how they are
built and how capable they are.

I'd never heard of a CU-50 RTD, and couldn't find anything except the one
image I
linked to.

I though one of you might provide more insight.

Bill

real

Post by William Couture
chart can't be found anywhere...
Bill

They're all real- it's just that there is no international standard
for Cu RTDs that I know of. You have not mentioned why you want this-
obviously if you are buying the sensor you are going to want to go to
the manufacturer for the data. If you are trying to make a general
purpose indicator or controller.. you might want to use this (assuming
the reference temperature of 25 C is appropriate..)
http://www.pyromation.com/Downloads/Data/427_c.pdf
Again, scale the numbers appropriately (5:1 in this case). Anything that's
within a degree or two C at the extremes is probably better than the sensor
interchangeability.
Where exactly did you run into a 50 ohm copper RTD?
--sp

Post by William Couture
Or possibly [OT] -- maybe I'm searching with the correct terms, but

I'm

Post by William Couture
trying to find
an resistance chart for a CU-50 RTD probe.
The best I've been able to come up with is this image, which isn't

quite

Post by William Couture
https://is.alicdn.com/img/pb/747/046/531/531046747_904.jpg
Pointers to something better?
Thanks!
Bill

http://www.thermometricscorp.com/PDFs/10_ohm_copper_rtd-0.

00427_in_C.PDF

Post by s***@interlog.com
Multiply numbers by 5.
OR
http://www.thermometricscorp.com/images/Accessories/
thermometricscorp_2129_12162627.gif
Halve these numbers.
depending on whether it's 50R at 0 degrees C or at 25 degrees C.
There may be others based on 75F or something.
Copper RTDs are all over place in terms of the quoted resistance (and
therefore the tempco) when you get down to the last decimal place or
two, AFAIK there is no standard.
One of the main applications would be homemade with a bit of wire left

over

Post by s***@interlog.com
from winding the motor, so annealing and exact composition would be
questionable.
--sp
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Post by William Couture
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Sean Breheny

2017-09-11 18:11:21 UTC

I've never heard of a Copper RTD. While Copper has quite a high tempco of
resistance, I think it is much more difficult to get a very accurate value
for it than it is for Platinum so most metal-based RTDs use Platinum.

Post by William Couture
I ran into this sensor when I bought a cheap Chinese controller -- it came
with one.
I write software for industrial process controllers professionally, and
occasionally buy
one of the cheap controllers I see around (aliexpress, ebay) just to see
how they are
built and how capable they are.
I'd never heard of a CU-50 RTD, and couldn't find anything except the one
image I
linked to.
I though one of you might provide more insight.
Bill

Post by William Couture
Both those charts have different thermal coefficients, and have

different

Post by William Couture
"zero" scales -- the 10R is 10R at 25C, the 100R is 100R at 0C.
the 10R chart multiplied by 5.5356 is closer, but it's strange that a

real

Post by William Couture
chart can't be found anywhere...
Bill

They're all real- it's just that there is no international standard
for Cu RTDs that I know of. You have not mentioned why you want this-
obviously if you are buying the sensor you are going to want to go to
the manufacturer for the data. If you are trying to make a general
purpose indicator or controller.. you might want to use this (assuming
the reference temperature of 25 C is appropriate..)
http://www.pyromation.com/Downloads/Data/427_c.pdf
Again, scale the numbers appropriately (5:1 in this case). Anything

that's

Post by s***@interlog.com
within a degree or two C at the extremes is probably better than the

sensor

Post by s***@interlog.com
interchangeability.
Where exactly did you run into a 50 ohm copper RTD?
--sp

Post by William Couture
Or possibly [OT] -- maybe I'm searching with the correct terms, but

I'm

Post by William Couture
trying to find
an resistance chart for a CU-50 RTD probe.
The best I've been able to come up with is this image, which isn't

quite

Post by William Couture
https://is.alicdn.com/img/pb/747/046/531/531046747_904.jpg
Pointers to something better?
Thanks!
Bill

http://www.thermometricscorp.com/PDFs/10_ohm_copper_rtd-0.

00427_in_C.PDF

over

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straycatblues.petfinder.org

Post by William Couture
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William Couture

2017-09-11 19:52:31 UTC

I had not heard of them, either. But I'm willing to bet copper is much
cheaper
than platinum, so the copper RTD gets used.

Bill

Post by Sean Breheny
I've never heard of a Copper RTD. While Copper has quite a high tempco of
resistance, I think it is much more difficult to get a very accurate value
for it than it is for Platinum so most metal-based RTDs use Platinum.

Post by William Couture
I ran into this sensor when I bought a cheap Chinese controller -- it

came

Post by William Couture
with one.
I write software for industrial process controllers professionally, and
occasionally buy
one of the cheap controllers I see around (aliexpress, ebay) just to see
how they are
built and how capable they are.
I'd never heard of a CU-50 RTD, and couldn't find anything except the one
image I
linked to.
I though one of you might provide more insight.
Bill

Post by William Couture
Both those charts have different thermal coefficients, and have

different

Post by William Couture
"zero" scales -- the 10R is 10R at 25C, the 100R is 100R at 0C.
the 10R chart multiplied by 5.5356 is closer, but it's strange that a

real

Post by William Couture
chart can't be found anywhere...
Bill

They're all real- it's just that there is no international standard
for Cu RTDs that I know of. You have not mentioned why you want this-
obviously if you are buying the sensor you are going to want to go to
the manufacturer for the data. If you are trying to make a general
purpose indicator or controller.. you might want to use this (assuming
the reference temperature of 25 C is appropriate..)
http://www.pyromation.com/Downloads/Data/427_c.pdf
Again, scale the numbers appropriately (5:1 in this case). Anything

that's

Post by s***@interlog.com
within a degree or two C at the extremes is probably better than the

sensor

Post by s***@interlog.com
interchangeability.
Where exactly did you run into a 50 ohm copper RTD?
--sp

Post by William Couture
Or possibly [OT] -- maybe I'm searching with the correct terms,

but

Post by s***@interlog.com
I'm

Post by William Couture
trying to find
an resistance chart for a CU-50 RTD probe.
The best I've been able to come up with is this image, which isn't

quite

Post by William Couture
https://is.alicdn.com/img/pb/747/046/531/531046747_904.jpg
Pointers to something better?
Thanks!
Bill

http://www.thermometricscorp.com/PDFs/10_ohm_copper_rtd-0.

00427_in_C.PDF

(and

Post by s***@interlog.com
therefore the tempco) when you get down to the last decimal place or
two, AFAIK there is no standard.
One of the main applications would be homemade with a bit of wire

left

Post by s***@interlog.com
over

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straycatblues.petfinder.org

Post by William Couture
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Post by William Couture
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Alan

2017-09-09 19:25:59 UTC

Bill,
Your link to
https://is.alicdn.com/img/pb/747/046/531/531046747_904.jpg
Leads me to a chart that while a bit fuzzy seems to be readable on my little iPad. For instance the device is 50 Ohm at 0c, 71.400 Ohm at 50c and 82.134 Ohm at 150c

The link someone sent for the 100 Ohm probe at
http://www.thermometricscorp.com/images/Accessories/thermometricscorp_2129_12162627.gif
Shows 100 Ohm at 0c, 142.108 at 100c, and 163.168 at 150c
Almost but not quite exactly 2x the 50 Ohm probe.

I would suggest that you figure out why you can't read your chart but if you can't figure it out, I could send you a screen shot from my iPad

Looking forward,
Al Shinn (Tinker)

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Alan

2017-09-09 21:19:23 UTC

Errata!
Oops that value of 71.400 Ohm is for 100c, not 50c! So sorry.

Looking forward,
Al Shinn (Tinker)

Post by Alan
Bill,
Your link to
https://is.alicdn.com/img/pb/747/046/531/531046747_904.jpg
Leads me to a chart that while a bit fuzzy seems to be readable on my little iPad. For instance the device is 50 Ohm at 0c, 71.400 Ohm at 50c and 82.134 Ohm at 150c
The link someone sent for the 100 Ohm probe at
http://www.thermometricscorp.com/images/Accessories/thermometricscorp_2129_12162627.gif
Shows 100 Ohm at 0c, 142.108 at 100c, and 163.168 at 150c
Almost but not quite exactly 2x the 50 Ohm probe.
I would suggest that you figure out why you can't read your chart but if you can't figure it out, I could send you a screen shot from my iPad
Looking forward,
Al Shinn (Tinker)

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Alan

2017-09-10 00:19:42 UTC

More than you wanna know about copper resistance with temperature:
http://nvlpubs.nist.gov/nistpubs/bulletin/07/nbsbulletinv7n1p71_A2b.pdf
Looking forward,
Al Shinn (Tinker)

Post by Alan
Errata!
Oops that value of 71.400 Ohm is for 100c, not 50c! So sorry.
Looking forward,
Al Shinn (Tinker)

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William Couture

2017-09-11 17:58:23 UTC