Pete Moss

Encoder connection to Micrologix 1100

22 posts in this topic

I have been tasked with collecting linear footage data of our product; after exiting the extruder it contacts a measuring wheel attached to an BEI encoder 28V/V. I've connected the ML1100 24 volt to the encoder and landed channel A to the high spped input on the ML1100. No count is produced, however when I put my meter on the input I see near line voltage.

Any thoughts anybody?

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You day you are seeing line voltage on that input. I assume you're also seeing it drop to zero and the input indicator is flashing on and off?

Chances are it's in your mode setting. What is your mode set to? Here's a quick video I didn't to help someone with their counter configuration. You might find it helpful.

https://youtu.be/1eDmN_tvXb4

 

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I saw your video previously; didn't see anything applicaple to me. I am not seeing a drop to zero, not seeing a frequency at I:O/0. In mode 1.

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I added a line of code with a MOV instruction to mov the the HSC.0.ACC to N7:11. The encoder is incremental with A,B,Z and complimentary A,B,Z however I am only using the A channel connect to I:0/0. I have the cut sheet, powered the encoder with the PLC 24 VDC, and using the (A) for a pulse. I didn't see anything is help on configuring the PLC channel

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http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1763-rm001_-en-p.pdf

Read page 107.  Logix500 online help will only have so much information.  High-speed inputs are masked to HSCx registers.  You will get more precision by using the quadrature encoder instead of using a single channel.

http://www.infoplc.net/files/descargas/rockwell/infoPLC_net_hsc_quick_start.pdf

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I've been thru 107 several times and the quick start guide. I'm using a bei xh25d-ss-2500-abzc-28v/v-em18 

http://www.beisensors.com/pdfs/h25-optical-incremental_encoder.pdf

and have tried attaching A and B to I:0/0 and I:o/1 respectively, it seems as thought the line voltage (absent 1 volt maybe) is always present on those two channels. Do you see anything with that encoder that would cause incompatibility issues? I have D connected to PLC +24 - F connected to common - A to I:O/0 and B to I:O/1

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What do you have to com0?

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Can you post a screenshot of the HSC tab, so we can see the status of the configuration and the channel?  

 

Micro1100HSC.jpg

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It appears that Pete is attempting to connect an encoder with differential output as though it was single-ended output.

That won't work.

re quadrature: this refers to the 90-degree phase difference between the A & B channels which enables detecting the direction of rotation. It does not refer to counting the rising and falling edges of pulses on both channels to give resolution equal to 4 times the number of lines on the encoder disc.

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Gerry is right, that is different interface

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On ‎11‎/‎2‎/‎2016 at 8:12 PM, Gerry said:

It appears that Pete is attempting to connect an encoder with differential output as though it was single-ended output.

That won't work.

re quadrature: this refers to the 90-degree phase difference between the A & B channels which enables detecting the direction of rotation. It does not refer to counting the rising and falling edges of pulses on both channels to give resolution equal to 4 times the number of lines on the encoder disc.

My understanding of this encoder is A channel outputs 2500 PPR and B channel does the same, only 90 degrees out of phase with A channel; therefore I can use A channel alone to caputure those pulses. I would disgaree with Gerry.

I've corrected the problem of not reading pulses, the issue was sinking rather than sourcing. The problem I have now is the use of HSC within the ML1100; perhaps one of you have written code using this feature. It seems as though when the ACC gets into the 10s of thousands, it faults the controller (overflow trap). I simply need to capture the encoder data, covert to a            measurement in feet and store the result. I move the ACC to N7:11, but i seem to faulting during this move. Any suggestions?

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N7 is only good for -32768 to +32767 then yes, it will fault the processor on an overflow.  How large of number do you need?  A long integer (32 bit) would get you to −2,147,483,648 to 2,147,483,647.  If you need more or less than that then you will need to write code to deal with the rollover.

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Mover the ACC register into a DINT or a Float, that should keep the HSC register from faulting the processor on math overflow.

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7 hours ago, Pete Moss said:

My understanding of this encoder is A channel outputs 2500 PPR and B channel does the same, only 90 degrees out of phase with A channel; therefore I can use A channel alone to caputure those pulses. I would disgaree with Gerry.

I've corrected the problem of not reading pulses, the issue was sinking rather than sourcing. The problem I have now is the use of HSC within the ML1100; perhaps one of you have written code using this feature. It seems as though when the ACC gets into the 10s of thousands, it faults the controller (overflow trap). I simply need to capture the encoder data, covert to a            measurement in feet and store the result. I move the ACC to N7:11, but i seem to faulting during this move. Any suggestions?

I didn't say you couldn't use only one channel for your application. I was pointing out that an encoder with "complementary" outputs is probably a differential output model.

Do you understand the difference between differential and single-ended interface?

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I personally always set "Auto Start" and "Counting Enabled" to "1" when using HSC

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Create a Long type data file like L9 (is the same as a DINT in RSLogix 5000) and move the ACC value to an element of this file like L9:0. This should work.

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good day.
Could you help me, I have a project similar to the one you comment on. But I don't know how to connect the encoder to the PLC and the configuration I'm checking.
Can you help me with an example and the diagram if you can.
I have been watching the videos and they are serving me a lot, but I still need to know how to connect it.

Thank you.

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Hard for anyone to give you help when you provide no information.

Start by telling us the model of PLC, model of encoder.  Then someone can provide you some guidance.

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yup... we can try to help, but due to GIGO principle you will likely not be satisfied with replies. Here is as detailed response as i can muster:

read PLC manual to determine type of available encoder interface. then find encoder with same type of interface. connect the two using info in product manuals. 

but as mentioned, i doubt it provided details you were looking for.

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@panic mode that's about as nice a way as one could say RTFM , I'll have to borrow that some time if you don't mind.

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go ahead  :-) 

i was also told that i sometimes scare people ...i am just trying to be softer here and there... :kewl:

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