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Member
stéphane.belche
Posts: 8
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Bad readings with CFP-RTD-124

Hi,

I have a compact field point system to record t° measurements on a machine (to replace a YOKOGAWA paper recorder system)

This machine is equiped with Thermocouple and RTD sensor

TC acquisition boards are CFP-TC-120. Readings are ok

RTD acquisition boards are CFP-RTD-124. Reading are nok  : see picture attached

With the previous YOKO system readings were stable and did not show any fast variations.

If i take resistance measurements, value is also stable.

CFP-RTD-124 used is revision H (187208H-02)

In advance thanks for your support.

Regards

Stéphane

Knight of NI
RavensFan
Posts: 16,072
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Re: Bad readings with CFP-RTD-124

To me, it looks like just a little bit of electrical noise.  You've collected 10's to 100's of data points in a 2 second period and it looks like the results are +/- 1 degree.  (The VI isn't clear as to whether this is °C or °F)

I might be wrong, but I think the thermocouple modules have some internal filtering to eliminate noise.  I've never used the RTD module to know, but perhaps it doesn't.  Or maybe there is a setting in MAX to turn it on.

Does your temperature change so rapidly that you'd need to read numerous data points per second?  The screenshot doesn't look like it is.  One possibility would be to so some averaging across multiple data points and plot that result.

Member
stéphane.belche
Posts: 8
0 Kudos

Re: Bad readings with CFP-RTD-124

I used the shared variable engine from the dsc package. This engine is recording automatically in a database value  I do not know if it is possible to adjust the measurement period.
For sure i do not need this fast reading.
The values are recorded in a Citadel database on the PC.
The only thing possible is to adjust the
Member
stéphane.belche
Posts: 8
0 Kudos

Re: Bad readings with CFP-RTD-124

I used the shared variable engine from the dsc package. This engine is recording automatically in a database value when  I do not know if it is possible to adjust the measurement period.
For sure i do not need this fast reading.
The values are recorded in a Citadel database on the PC.
The only thing possible is to adjust the
Member
stéphane.belche
Posts: 8
0 Kudos

Re: Bad readings with CFP-RTD-124

I used the shared variable engine from the dsc package. This engine is recording automatically in a database value when there  I do not know if it is possible to adjust the measurement period.
For sure i do not need this fast reading.
The values are recorded in a Citadel database on the PC.
The only thing possible is to adjust the
Member
stéphane.belche
Posts: 8
0 Kudos

Re: Bad readings with CFP-RTD-124

I used the shared variable engine from the dsc package. This engine is recording automatically in a database value when there is a  I do not know if it is possible to adjust the measurement period.
For sure i do not need this fast reading.
The values are recorded in a Citadel database on the PC.
The only thing possible is to adjust the
Member
stéphane.belche
Posts: 8
0 Kudos

Re: Bad readings with CFP-RTD-124

Sorry there is something wrong , the message is now there a couple of times...
Member
elmer85002
Posts: 3
0 Kudos

Re: Bad readings with CFP-RTD-124

Hey there, I'm also having the same problem as you do.  What i did to solve it was to change the cpf-RTD-122 power supply for a DC variable lab Power supply, that corrected the issue right away.  now what im  trying to do is to find out why it won't work with the field point power supply or with another power supply.

Regards

Elmer Rodriguez

R&D Engineer