Another CPU313C - measuring time with OB35

[idell]

Hi! here is my code in OB35 - configured to 100ms

L time_min //time_min real variable  
L 1.666667E-3 //add 0.001667 minute each 100 ms (1min = 1/60000ms*100ms=0.001667)  
+R  
T time_min

with simulator it works fine,real time 1min - i get 0.999 .. 1.001min
with CPU i have - real time 1min - i get 1.15 ...1.2min

i also tried to use,this code, triggering by 5th bit of clock memory bit word in ob1, the results is better 0.95 .. 0.96, these results still aren't good enough.

how to "measure" the time the most exactly ?
I want to know how long our installation works for customer.

 

[L D[AR2P#0.0]]

Use SFC1 to read the clock and store the time at the start of your event, then same again at then end of the event. Calculate the difference in time.