about S7-200 EM231 RTD connect to Pt10000

notcool

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• Oct 20, 2005

• #1

Hello everybody

My plc is S7-200 CPU226+EM231 AI2×RTD，when connect to Pt100 all is OK,i.e. when the temperature is 30 ℃，the data AIW0 is about 300(I use the channel one).but when I change Pt100 to Pt10000,the dip switch setting to 11011001,according to the EM231 RTD manual,the data AIW0×0.1=temperature value ,but now the data AIW0×0.1≠temperature value ,why?

 

Damir

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• Oct 21, 2005

• #2

How big is your deviation ?
Did you shut off the analog filters at system data block ?

 

Damir

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• Oct 21, 2005

• #3

Turn off yout CPU when changing DIP switches. The EMs overtake settings at power on only.

 

notcool

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• Oct 23, 2005

• #4

thanks Damir

when the temperature is 37℃，the data AIW0 is about 920,when temperature is 85℃,the data AIW0 is about 2200;
When changing DIP switches,I have turn power on/off several times,

 

Damir

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• Oct 24, 2005

• #5

this sounds strange.

There are multiple dip settings for the different PT1000 types.

Did you measured the resistance of your PT1000 at a defined tempreature and compared with his datasheet?
Maybe you had a PT100 with a different alpha value.

Otherwise i would try a another module if applicable or change this one.

 

notcool

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• Oct 24, 2005

• #6

not PT1000,I think it's PT10000(α=0.003850?） ,because when temperature=25℃,the resistance is about 10K Ω ，I have changed another module and new one PT10000,the result is the same.