Calculating meters

Hello,

I´m new with logo and I have a problem with calculating meters on plastic film line. I have a roller diameter 60mm with one proximity sensor,  that gives me one pulse 188,5mm per one spin.

Line speed is about 20m/min.

How can I calculate the result  to be 1000mm?

Any help would be appreciated.

Regards,

Raimo

1000mm is not possible, because 1000mm is not an even multiple of 188,5mm. You can scale the length value in mm, but only in steps of 188,5mm plus roundings on fully mm. See example in attachment with some comments.

Regards, Scorp

Thank You mr. Scorp for quick answer, this is exactly what I was looking for!

I changed mathematic instruction values V2 to 1834 and V3 to 11, now i get exactly 1000mm.

With many Thanks,

Best Regards,

Raimo.

Sauppari

Thank You mr. Scorp for quick answer, this is exactly what I was looking for!

I changed mathematic instruction values V2 to 1834 and V3 to 11, now i get exactly 1000mm.

With many Thanks,

Best Regards,

Raimo.

Maybe the display will show exactly 1000mm, but the true length is not 1000mm. 1834mm/11=166.73mm, but you have a diameter of 60mm x Pi = 188,5mm. You can't select the values as you want, when the display value should match with the true length.

Regards, Scorp

Okay,

You´re right again.

Thats the difference between simulation and a real thing.

I´m learning more all the time ..

Thanks again,

Raimo

Maybe an incremental encoder with e.g. 100-300 pulses per rotation would be a better solution for your project instead of a proximity switch with 1 pulse per rotation. Then the 188,5mm between two pulses would be decreased to a much smaller value, e.g. 5-10mm between two pulses. This will increase the resolution enormously.

If this is possible for you, then be careful not to exceed the maximum frequency of the fast counter input (5kHz) and not all Logo controllers have fast counter inputs.

Regards, Scorp