Compact Logix Programming Help

HI I am a beginner Programmer and am trying to set up a simple line speed reference using a rotary encoder in to a high speed counter on a L24ER QBFC1B and out of analog to a power flex drive does anyone have any sample instruction that could get me started Thanks in advance.

Welcome to the Forum !

The more information you can give, the better the answers you will get.

What you are describing sounds to me like a "velocity follower", where there is an encoder connected to a moving belt or mechanism, and you are trying to get an AC drive to follow that encoder's speed.

The 1769-L24ER-QBFC1B controller, as you have seen, has a 4-channel high-speed counter module embedded in it. It is similar, but not identical, to the 1769-HSC High Speed Counter module.

This isn't a motion axis; it's really meant for taking discrete actions on embedded Outputs based on fast encoder counts coming into the module.

I have not used the L24ER-QBFC1B controller personally, but from what I understand it is most similar to the 1769-HSC. Get the HSC user manual, Publication 1769-UM006, from the RA Literature Library.

Set the counter up as a Ring Counter. For the maximum count, let's go ahead and enter the number of counts your encoder goes through in one revolution.

Then look at the automatically-defined Module Tags created for the module. You'll see a tag like Local:3:I.Ctr0CurrentRate, which should tell you the number of pulses per second you are seeing from the encoder. Detailed information on the Cyclic Rate mode starts on Page 32 of the User Manual.

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1769-um021_-en-p.pdf

Embedded HSC counters, starting at page 189.
Embedded Analog I/O, starting at page 199.
Chapter 10 addresses application development.

For the PowerFlex drive, depending of the VFD's type, study the respective User/Reference Manuals from within:

http://literature.rockwellautomation.com/idc/groups/public/documents/webassets/browse_category.hcst
Drives (Allen-Bradley).

Thanks guys lot of good info I know there is several different ways of programming this with all types of instruction but is there any one way that's better or easier thanks

The first step is to just do the configuration part; the High-Speed Counter will give you a value for the Rate without having any instructions at all in your program, if you configure it correctly.

The more effort you show, the more help you will get.