Cycle time, interruption + counting

[pszczepan 2]

Hi ! I have problem with screws correct counting, which come 200 pcs per minute At the beginning cycle time was about 14 and everything was all right. I wanted count 50 I had real 50. Later when the program expanded - cycle time bacame 2.5 ms and real 50 pcs I counted as 46-47. It meant I didn not count enough fast. I decided to use interruption. First it was counting in counting mode; simple - every 50 pcs I had subroutine. It worked, but I counted 54-56 instead of 50. The problem is that screws have threads and sometimes sensor gave two signals for one screw - it is my idea - maybe I do something wrong in my program; I do not use IORF function - How I can apply it? I can not set smaller sensitivity for my sensor - It is now. I think that I should have something like - switch on delay. I tried to use STIM function, but I do not see any positive effect I would like to have input signal which starts subroutine when some time past. Please help me how I can get it. Thanks Pawel Edited 26 Apr 2006 by pszczepan

[gtsuport 61]

I think you may be correct with your idea of the sensor giving multiple counts per piece. Perhaps a different sensor would solve the problem. No amount of programming will help if the plc is not getting good information.