Originally created by: H87

i'm new at CoDeSys. and i'm wondering how to make a program counting input pulses.

This is the case:

I got a movment sensor placed at my door. And i wanna see on my plc program how manny has enterd the room. So every time the input is high i want the program to count 1. and if it gets high again, then is 2 and so on.

And ofc a reset button.

Would be awsome if someone can help me.

Best regards

Henrik

the line should be something like

IF R_TRIG (pulse) then counter:= counter+1; END_IF;

IF R_TRIG (reset) then counter:=0;END_IF;

also F_TRIG is possible.

lots of other possibilities like using a function block CNT etc.

in simulation you will not see this pulse as it is only one cycle.

if you want to know how many people are in then you will need two pulsemachines and check the sequence of them.

Hi Henrik,

Shooter is almost right, however, you need to declare instances of the R_TRIGs and F_TRIGs, then it will work

VAR
  Sensor    : BOOL;
  Reset     : BOOL;
  CountTrig : R_TRIG; (* to catch the rising signal edge *)
  ClearTrig : F_TRIG; (* to catch the falling signal edge *)
  Count     : INT;
END_VAR

CountTrig (CLK := Sensor); (* finds the counting up events *)
ClearTrig (CLK := Reset); (* finds the clear commands *)
IF CountTrig.Q
THEN Count := Count+1;
END_IF;
IF ClearTrig.Q
THEN Count := 0;
END_IF;

That's quite easy to understand I hope.

Details of the standard FBs such as R_TRIG or F_TRIG you should find in the CoDeSys online help, or on the internet at IEC61131 related websites.

Regards

Rolf

You may want a short time delay on the count in case the signal bounces a few times as the person starts to actuate the sensor.

and to finish rolf

Sensor at %IX0.0 : BOOL;

Reset at %IX0.1 : BOOL;

just to be sure you have inputs from the PLC.

yes rolf is my teacher i am always a little short in the corners.

and norman is also correct, but timers do not come in lecture 1 but in lecture 3.

Originally created by: H87

Thank you very much guys. Its working perfect.

But now i have another case: I have tryed manny diferent things, but it wont work as atended.

Case is: i dont want a reset button annymore. so i installed a second movment sensor at the door. so they are standing next to each other.

So i want the sensors to detect how manny is going in and how manny is going out

-So if signal for sensor 1 is detected first = someone is going in to the room (count 1 up)

-But if signal from sensor 2 is detected first = someone is leaving the room (count 1 down)

Sorry for bothering you guys. But I'm still a newbi. Promise to get bether

Best regards

Henrik

easy one, oja still newbie.

i would recommend a course at plcs.net.

if sensor 1 on and sensor 2 off then someone enters.

if sensor 2 on and sensor 1 off somenone leaves.