PTO controll by rpm sensor

Hi, I am getting stuck on programming a logo 8.

For a project i am controlling a pto at a maximum rpm. i want to close a valve at a maximum of 2800 rpm and when it drops down to 2200rpm i want to open it again.

the sensor at the fast input of the logo gives 8 pulses each rotation of the pto.

also i want to show the rpm on the logo display. i tried to use some of the examples given on this forum but i get stuck on the mathematical settings on some blocks.

can someone with more experience help me out and give me a kick in the right direction?

regards ls

aah somthing went wrong with zipping the file, my apologies.

The program in this zip file i used as a base for the rpm part in my program, i found it on this forum (thanks for that).

My total program is a network of 6 plc's

i dont now if i use a setting of 18000 in block b004 (calculation of speed) is accurat for my type of sensingi

thank you for your reply. but my input sensor gives 8 signals a rotation so it must be times 8 i think?

It would be easier to change the time of the threshold trigger. With 7.5s (60/8) you get out the rpm directly, but this time is too long for reactions. Therefore use 0.75s, then you have the tens of the rpm. Change On to 280 and Off to 220 to get your desired switching levels.

And forget your complicated calculation of your speed, you can calculate it directly with the output of the threshold trigger.

Regards, Scorp