how to use encoder with micrologic1200

[Guest Guest_rock]

Have a micrologix 1200 plc and curious how to connect a encoder to it. The encoder outputs 720 pulses per revolution. Could someone post a example of how to connect the encoder and scale the encoder input so that for one revolution, the 720 would be scaled to be 0-360. Have just finished doing this with a omron cqm1 after reading some post on this site ( could not have figured it out without the posted info ), and now wanting to possibly do the same thing with a Allen Bradley. have done some programming with the Allen Bradley in the last few months, but it was just simple motor control, indexing by shifting bits etc. Any advice would be helpful

[Ken Moore 23]

As with most PLC challenges, there is always more than one way to do something. One possible solution is to use a STI. For the sake of arguement let' say it's a 1 second STI. So...subtract the previous counter value from the last value, this will give you the number of pulses that occured in the last second. Then using simple math we can calculate the RPM. (pulses per second) * (60) = pusles per minute (pulses per minute) / 720 = Revolutions per minute I just re-read your post, you're not looking for RPM's so ignore the previous rubbish. You want to convert 0-760 pulses to 0-360, my first question is why? With 720 you get a pulse every 1/2 degree versus 1 pulse per degree, twice the resolution. Are you just trying to make the rest of your program easier? So that if you looking or 43 degrees you don't have to do any calculations? In my opinion you should keep the higher resoultion and handle the 2 pulses per degree in the Ladder Logic. Just my $1.298 worth. KEN

[kcor 1]

Am always trying to make the rest of my program easier, the only way I can understand how to do it. The reason that I am scaling the 720 pulses to 360, is so that on a operator screen I display a value of 0-360 for the tech's and operator to see and adjust, because the main cam makes one complete revolution per index or 360 degrees. Thanks for your input