StarWing

FX3U simple positioning

6 posts in this topic

This is kinda of a "can you do it for me" question, but I'm not able to work it out by myself from the start. If I can get some examples or hints, I can probably figure the rest out by myself.

So here it goes. The whole thing is a proof of concept, but I want to look if both devices can work together in a working manner.

I have a leftover Mdrive stepper motor which I want to connect to a FX3U plc. I'm planning to use/test this setup as a linear feeding machine. I will use a external encoder (A-B channel) to read/verify the distance feeded.

Since I only have a FX3U 24MR unit available, I'll need an transistor output module.

The program should be something like:

-put a value in a register (distance wanted, in mm, converted to pulses in the PLC) with a GOT unit or something

-start feeding and readout the value of the encoder (1000 p/rev)

-on 80-90% of the total distance wanted, speed should go down and stop the motor.

-An alternative should be that I use 2 values in the register, 1 for total distance wanted and 1 to slow down to the total distance.

-the feeder can be somewhat off, the project does not require exact positioning (1-2mm is no issue)

The Mdrive wants 2 inputs, 1 with pulses on a given frequency and 1 for the direction.

I have already looked through the (positioning) manuals, but I'm unable to put something toghether. Parameters for ramp down/ramp up/ limits should be no issue, these I can figure out by myself.

As far as I found out, I should be able to drive the Mdrive directly from the PLC as the inputs are 24V.

 

Any help will be highly appreciated !!

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Looks simple enough. FX3U aleasy has High speed inputs which you can use for the encoder. take a look at the C200 + High speed counter in your FX3U porgramming manual.

You also have the high speed instructions like PLSY. Take a look at those as well. 

Then If you have any questions. Let us know

 

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"Since I only have a FX3U 24MR unit available, I'll need an transistor output module."

do you mean a transistor ouput expansion block on the side of the existing FX3U?

I think you may need FX3U transistor output base unit.

If you need to use the high speed output commands PLSY, DRVI,DRVA etc I think you can only use Y0 to Y2?

I think DRVI would do what you want without the need for encoder feedback.

See attached.

 

 

 

 

position prg.JPG

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@Veganic, you are correct, I'm talking about a expansion module. I'll doublecheck this with my supplier.

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Unless you're talking a really slow pulse train, you will either need to get a transistor base unit, or an FX3U-1PG special function module. Only the first three outputs of a transistor base unit will work with the high-speed commands like PLSY, DRVI, and DRVA. The FX3U-1PG uses standard FROM/TO commands to set up and execute the motion. Using the built-in commands with the base unit is much easier, so I would highly recommend replacing the base unit.

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Posted (edited)

How about FX3U-2HSY-ADP

http://dl.mitsubishielectric.com/dl/fa/document/manual/plc_fx/jy997d16401(e)/jy997d16401(e)e.pdf

If you don't need more complex instructions... scaling for example, you can buy cheap Fx3G. Advantage is the built in USB port.

Or Fx3GE with ehternet port. Both works great for simple positioning tasks. Yo don't need encoder!

Pay atention what type of output you need... sync or source.

Edited by glavanov

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