elevmike
Member
I'm missing something, What's the issue here? I think the main problem is playing 1000 questions...
Anyway..The problem as I see it is you are thinking in terms of inches, and not counts, when you actually dont care how many inches-feet the carriers are spaced, but how many COUNTS.
Actually you have ~180 counts between carriers. (360ppr encoder x 1 rev = 2 carriers..360/2=180...579 Carriers x 180 counts per = 104,220. You should be able to count to 104K. My guess is the counts between carriers is not a whole number..all the time, which would cause an accumulating error.
Therefore:
Each carrier has a count value, 1=0, 2=180, 3=360, 4=540..etc..Each carrier is represented by a stored count value. If the count is 180 the conveyer is at carrier 2. So if your looking for the artical on carrier 251, you zoom the conveyer to count 44,640 then slow to 45,000 and stop. This will allow you to track the carriers in BOTH directions..like say your at carrier 150 and want to go to carrier 52, you can go in reverse.
BTW, when you approch carrier 1 from either direction you'll need to slowdown that speedy 160fpm conveyer then slowly pass a "reset encoder" target on the conveyer, past a static prox switch, or eye. The reason is that logic required to reset the encoder is slower then the counter. If your conveyer is zipping at full speed when resetting the count then you will be off on your count due to the fact that the count is accumulating faster then the PLC scan time. YOU MUST GO SLOW (10 fpm or so) to get an accurate reset for the count...
Anyway..The problem as I see it is you are thinking in terms of inches, and not counts, when you actually dont care how many inches-feet the carriers are spaced, but how many COUNTS.
Actually you have ~180 counts between carriers. (360ppr encoder x 1 rev = 2 carriers..360/2=180...579 Carriers x 180 counts per = 104,220. You should be able to count to 104K. My guess is the counts between carriers is not a whole number..all the time, which would cause an accumulating error.
Therefore:
Each carrier has a count value, 1=0, 2=180, 3=360, 4=540..etc..Each carrier is represented by a stored count value. If the count is 180 the conveyer is at carrier 2. So if your looking for the artical on carrier 251, you zoom the conveyer to count 44,640 then slow to 45,000 and stop. This will allow you to track the carriers in BOTH directions..like say your at carrier 150 and want to go to carrier 52, you can go in reverse.
BTW, when you approch carrier 1 from either direction you'll need to slowdown that speedy 160fpm conveyer then slowly pass a "reset encoder" target on the conveyer, past a static prox switch, or eye. The reason is that logic required to reset the encoder is slower then the counter. If your conveyer is zipping at full speed when resetting the count then you will be off on your count due to the fact that the count is accumulating faster then the PLC scan time. YOU MUST GO SLOW (10 fpm or so) to get an accurate reset for the count...
