Incremental Encoder With Slc500

[mac_g3 0]

Hello All. I have a AB SLC500 PLC, the CPU model is : 1747-L532 serD / OS302. I have a incremantal encoder, with the standard of three signals: -Channel A, channel B, and channel Z. ************************************************************** The encoder is a IVO GI355 model, with differential outputs, the Z output is true when A and B channels is true. When the axis turn right, i have channel A true before the channel B true , next channel A and B is true, next channel A false (B is true), and last A and B is false. When the axis turn left, i have channel B true before the channel A true , next channel A and B is true, next channel B false (A is true), and last A and B is false. ************************************************************** I want to connect the encoder to 1746-ITV16 (16 fast inputs board). I don't know how to make a program to manage the encoder. I want : -When the encoder axis turn rights, a counter C5:0 increase counts; -When the encoder axis turn lefts, the same counter decrease counts; -When the Z inputs is true , the accumulate value in C5:0 equals 0. Anyones can help me ? .. with a RSLogix500 sample file .. or a precise screen copy ? . Thanks for yours answers, and greetings from France ! Stéphane.

[TimWilborne 108]

First a question. Do you already have the ITV16? I am not saying that it can't be done or it will be hard because I am not sure yet, but it would be much easier with something like a HSCE2 or some type on High Speed Counter module that can be configured for quadrature encoders. I don't think the ITV16 can be simply configured for it

[rswolff 9]

You forgot to include the rotational speed of the encoder when it will be in operation. To count correctly you would need to know which signal (A or B) is leading the other. This requires the module and program scan be capable of capturing these signals for every change in the signal lines. I would expect for any normal encoder application that this would not be possible. Therefore, you could not determine with any accuracy the actual counting. As the previous answer indicated, using a HSCE would be a better approach. This would count correcty unless you exceeded its specified frequency, which can be determined by the rotational speed and resolution of the encoder.

[Ken Moore 23]

I prefer the Spectrum 1746sc-CTR4, you get four channels for less money than the HSCE, plus it doesn't have the 32767 limitation. Spectrum is an AB partner, so you can get them from you local AB dist. http://www.spectrumcontrols.com/ab-1746.html

[hipoint2 0]

I agree with the above, using a high speed counter. If you try to do it in the program you may miss a couple of counts due to scans, where as the module does not care about the scans and still keeps track of the counts and it will do everything you said you need to do.

[TimWilborne 108]

I have never used the Spectrum module that Ken suggest but I think I would look at that. More channels for less money and while an Encompass Partner does not give the product any guarantees, it does say that it should work very well with the SLC