Math Error...I think...Help

I’m trying to write a program that calculates OEE. However, When I run the code I get stack errors. I’m pretty sure it’s because some calculation could be dividing by zero. How do you deal with math functions that could be dividing by zero?



I've attached the exported code
VAR
Availability: REAL; (*Total Time the Line/Cell is available to run production in minutes*)
Downtime: REAL; (*Total Time the Line/Cell is down not making parts in minutes*)
Total_Parts: DINT; (*Total parts processed. Including passed and failed parts*)
Good_Parts: DINT; (*Total parts passed*)
Ideal_Run_Rate_per_min: REAL; (*Ideal Parts per minute rate. This is an expected value i.e. 5 parts required per minute.*)

(*output values are all in percentage*)
Oee_Availability: REAL;
Oee_Performance: REAL;
Oee_Quality: REAL;
Oee_Overall: REAL;
END_VAR





Oee_Availability:=((Availability-Downtime)/Availability)*100;

Oee_Performance:=((Total_Parts/(Availability-Downtime))/Ideal_Run_Rate_per_min)*100;

IF Oee_Performance>100 THEN
Oee_Performance:=100;
END_IF

Oee_Quality:=(Good_Parts/Total_Parts)*100;

Oee_Overall:=(Oee_Availability*Oee_Performance*Oee_Quality)/10000;

How do you deal with math functions that could be dividing by zero?

Click to expand...

Check the value before the divide would be one method.

Here is the error. Line 3 is high lighed in red after the error.

lostcontrol said:

Check the value before the divide would be one method.

Click to expand...

OK, I tried this to prevent dividing by zero


IF (Availability-Downtime)>0 AND Availability>0 AND Ideal_Run_Rate_per_min>0 AND Total_Parts>0 THEN

Oee_Availability:=((Availability-Downtime)/Availability)*100;

Oee_Performance:=((Total_Parts/(Availability-Downtime))/Ideal_Run_Rate_per_min)*100;

IF Oee_Performance>100 THEN
Oee_Performance:=100;
END_IF

Oee_Quality:=(Good_Parts/Total_Parts)*100;

ELSE
Oee_Availability:=0;
Oee_Performance:=0;
Oee_Quality:=0;
END_IF

Oee_Overall:=(Oee_Availability*Oee_Performance*Oee_Quality)/10000;

There is probably math you can simplify as well...

Oee_Availability:=((Availability-Downtime)/Availability)*100;

Click to expand...

This could be changed to:
100-(Downtime/Availabilty*100) will render the same result.

You could possibly do the others, I have to run...