need help! Commuting an encoder to PLC

[Sal]

I am building an elevator system of four level demo as a project for my school where I'm using an AB PLC5/20 and an encoder for positioning.
The encoder is OakGrigsby optical encoder 900 series with 128 ppr, quadrature outputs and is completely compatible with TTL circuits, it got 4 pins where two pins are for the 5VDC (+ and -) and the other two are the output channels (A and B), and the type of card I'm using to read out these pulses is AB 1771-IJ encoder/counter module, but it seems hard for me to figure how to interface between that encoder and this card to do the job and if so where to read these outputed pulses from what register or file of the PLC, I am new to this stuff, any idea is appreciated.

 

[Ron Beaufort]

Greetings Sal,

and welcome to the forum ... well actually to the practice area of the forum ... you’ll get a lot more answers to your question if you’ll post on the “Live Question and Answer” board in the future ...

anyway ... since you’re a student and doing this for a project I can’t just give you a direct answer (and actually I don’t know enough details about your actual hardware setup to do that anyway) ... but here are some ideas that might help get you started ...

you’re probably going to need Block Transfers to communicate with this module ... the book for the module is here:

link to 1771-IJ User Manual

unfortunately this manual has been around since the days of the old PLC-2 processors ... that means that many of the examples in the book might be difficult to understand ... I’d just read quickly through the book until you get back to page 6-9 ... that’s where the Block Transfer discussion begins ... then there are some rung examples on page 6-10 ...

so ... do you know anything at all about Block Transfers? ... if not, then this might help to giving you the general idea:

post about Block Transfers

read up on this material and post again if you need more help ... BUT ... if you post again, please tell us what programming software you’re using (RSLogix5, etc.) ... tell us what you’ve tried so far ... post any program code that you’ve already written ... we’ll try to help you over the hard parts ...

and incidentally ... this is a pretty ambitious project for someone who is “new to this stuff” ... so how long have you been working with PLCs anyway? ... what type of projects have you already accomplished? ...