regarding Analogue Inputs

N.Tufail

hello,i am applying analouge input ( simatic S7-200 CPU224-XP) while changing the resistance of potentiometer and as a result i want to turn led on and off on certain threshold .kindly help me how to do this,i am new on PLC.i shall be very thankful to all of you.

N.Tufail

thanks for the reply,but sir the problem is the analouge input gives the values in word,which is 16-bit.how can we put the threshold on say 800 ohm resistance(so that the LED turns on at 800 ohm and turns off at say 200ohm resistance).how can we make the plc understand that it has to turn on and off? i tried it,still i am trying but still cant do it.we stored the word in using VW100 comand,now how can we read the value which is stored in memory,and how can we put the threshhold accordingly,all the comparing blocks in lader logic are for comparing bytes not the words.we can not put any check,we have to convert the word into the byte....... :( hpe you got my point

N.Tufail

thanks for the reply,but sir the problem is the analouge input gives the values in word,which is 16-bit.how can we put the threshold on say 800 ohm resistance(so that the LED turns on at 800 ohm and turns off at say 200ohm resistance).how can we make the plc understand that it has to turn on and off? i tried it,still i am trying but still cant do it.we stored the word in using VW100 comand,now how can we read the value which is stored in memory,and how can we put the threshhold accordingly,all the comparing blocks in lader logic are for comparing bytes not the words.we can not put any check,we have to convert the word into the byte....... :( hpe you got my point

N.Tufail

thanks for the reply,but sir the problem is the analouge input gives the values in word,which is 16-bit.how can we put the threshold on say 800 ohm resistance(so that the LED turns on at 800 ohm and turns off at say 200ohm resistance).how can we make the plc understand that it has to turn on and off? i tried it,still i am trying but still cant do it.we stored the word in using VW100 comand,now how can we read the value which is stored in memory,and how can we put the threshhold accordingly,all the comparing blocks in lader logic are for comparing bytes not the words.we can not put any check,we have to convert the word into the byte....... :( hpe you got my point

Pranav J. Bhagat

N.Tufail

thanks for the reply,but sir the problem is the analouge input gives the values in word,which is 16-bit.how can we put the threshold on say 800 ohm resistance(so that the LED turns on at 800 ohm and turns off at say 200ohm resistance).how can we make the plc understand that it has to turn on and off? i tried it,still i am trying but still cant do it.we stored the word in using VW100 comand,now how can we read the value which is stored in memory,and how can we put the threshhold accordingly,all the comparing blocks in lader logic are for comparing bytes not the words.we can not put any check,we have to convert the word into the byte....... :( hpe you got my point

as solutionfinder says make connection to potentiometer. . Now use S_ITR Library, Check count for Low point of POT, which is Isl, Check count for high point Ish. . And put your desired range of POT in Ovl & Ovh. . The output you get will be your desired output in terms of oHm. . And as you are talking about comparison of word, then try comparison of INT (I) instead of word. .

N.Tufail

hello,i am applying analouge input ( simatic S7-200 CPU224-XP) while changing the resistance of potentiometer and as a result i want to turn led on and off on certain threshold .kindly help me how to do this,i am new on PLC.i shall be very thankful to all of you.