Programming help on Ge 90-30 PLC

J

Thread Starter

Javaboy

Hi friends;
I want to read the signal from pressure transmitter. 4 to 20 mA 0 to 50 PSiG.

I start like this:
%AI0001 input to the INT_TO_REAL block
Out of the block save in %R0001
I load the programme in cpu it shows 32667 at 4 ma. While i set the low and high limit in module configration is 00000 and 32000 respectively.

Somebody said you should do some work at refrence table but i can not understand how? I know after the INT_TO_REAL block done some work to change into Engneering units. But at that time i am confused that at 4 ma the counts are 00000 at R0001.

Please guide me and i need a example of ladder logic to understand it.
Secondly In Math function when i add SUB it shows SUB_INT block i need SUB_REAL how i get it in LM90 version 9.05.

Regards
 
When you apply 0 psig the pressure transmitter will give 4 mA. When you apply 50 psig the pressure transmitter give 20 mA. So if you have 0 counts in %AI0001 at 4 mA, this is the right value.
 
Thanks for reply.
But i get 32667 at 4 mA. why? I use the Rosemount transmitter model 3351 which is in smart transmiter catg.

Thanks
 
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