Scaling PT100 with schnider m211

Henrit

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May 2019
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Hello, can someone help me with scaling PT100 RTD useing Schnider m211 PLC? I can see the analoog value on the controller but once the temperature rises it starts to lie for an example 22°= analog value 340, but the since analog value 1000 is max it only goes up to 66°, but I know the temerature is higher. Maybee anyone has example for scaling this RTD or has any suggestions?
 
Normally you take the range of your instrument, e.g. 0 to 100 is a range of 100 and divide that by your analogue range, in this case 1000, which would give you 0.1degC per point of analogue.


You can then multiply this by the actual analogue reading, e.g. 200 x 0.1 = 20degC. This is OK so long as you instrument base reading is 0, if it is different then you need to add the base value. For example if you read 50-150degC, an analogue reading of 200 would equate to 150-50 divided by 1000-0 multiplied by 200 plus your base of 50 = 70.



What hardware are you using as there is a particular module for the M221 range, and in that module you configure your instrument type and range and it will give you the correct reading. To me it sounds like you are connecting a PT100 direct to the analogue input which won't work.
 
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What hardware are you using as there is a particular module for the M221 range, and in that module you configure your instrument type and range and it will give you the correct reading. To me it sounds like you are connecting a PT100 direct to the analogue input which won't work.

As Jonnie said you need a Expansion I/O for the PT100, they have several that will work with the M221's

Click on Temp on the left side https://www.schneider-electric.com/en/product-range/62131-modicon-tm3/166401149-analog-i-os/
 
I am have expansion module from Mitsubishi Alpha that is for PT100 ment in particular for PT100 and the sensor should read from -50°- 400° so I think -50° should 0 and 400° should be 1000.
 
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I have exapnsion from alpha to get a reading from pt100, but it is connected to m221 analog input that is built in to m211 plc. So the order is 1.pt100 2.alpha pt100 module 3.schneider m221 plc analog input.
 
So are you actually sending an analogue signal to the M221? The way you've written it doesn't detail that. How does the signal get from the Alpha, do you have an analogue output to drive the M221 input?

PT100 and analogue signals are different, that's why you have particular modules. The M221 will also only accept 0-10V if you are using the inbuilt analogue inputs.
 
So are you actually sending an analogue signal to the M221? The way you've written it doesn't detail that. How does the signal get from the Alpha, do you have an analogue output to drive the M221 input?

PT100 and analogue signals are different, that's why you have particular modules. The M221 will also only accept 0-10V if you are using the inbuilt analogue inputs.


The module(alpha temperaturemodul) that is between the PT100 and M221 is meant for converting signal from pt100 to analog value (0-10v). Do you think since they are not from the same brand they may not work with each other? I did notice that the module has - 50Deg- 200Deg written on it, but the sensor is - 50Deg- 400Deg, may this be the issue?

Link to alpha module
https://www.google.com/search?q=alp...oECAwQAQ&biw=360&bih=631#imgrc=T2KlWz6LzcIYcM
 
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Have you got part numbers so I can have a look? The only Alpha PT100 module I can find doesn't show that it has an analogue output. Do you have an analogue output module for the Alpha?


Brand doesn't matter it will work if you have the right hardware.
 
Ok, I've had a look, and yes the fact that you have a sensor outside of the operating parameters of the module will be an issue. Why are you not wiring the PT100 to the M221?
 
Ok, I've had a look, and yes the fact that you have a sensor outside of the operating parameters of the module will be an issue. Why are you not wiring the PT100 to the M221?

Do you mean directly do to the analoog input? I thought that it would not work.
 
You can buy PT100 to analog converters in various formats i.e. 0-10v 4-20ma 0-20ma and pre-scaled i.e. 0-150.0 0c to 4-20ma these are cheap so makes sense.
 
Do you mean directly do to the analoog input? I thought that it would not work.


No you can buy modules that fit on the M221 to take in a PT100 directly.



As parky has said another option is a converter like you have with the Alpha, although one that is correct for your application. I just bought one in the UK programmed for -50 to 250 with a 4-20mA output for £37 + VAT.
 
No you can buy modules that fit on the M221 to take in a PT100 directly.



As parky has said another option is a converter like you have with the Alpha, although one that is correct for your application. I just bought one in the UK programmed for -50 to 250 with a 4-20mA output for £37 + VAT.

Or if i buy the sensor that has range from -50deg-200deg
then the module i have should work?
 
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