Getting motion from a stepper motor?

[Gary]

This is a typical PLC application and is quite simple and inexpensive.

I have been tasked with a small project for the day-job, we need a feed/rewind system for a foil printing machine.

Its a simple task - the device needs to take a start signal from the machine, accelerate a motor, run for a preset time, decelerate and stop.

Now, we can either go with a timed duration and adjustable speed or a fixed duration taken from the machine as a start & stop signal with adjustable speed.

The speed needs to be adjustable as the machine is variable speed and also the amount of foil to feed will vary depending on the job design.

So, my question is - how simple can we make this?

I would go straight for a Nema23, 4NM motor i think with a step/dir drive and simple PSU - these I have proven to be tough little cookies on my other machines.

But the control side - how would i look to achieve the speed ramping and velocity in the simplest way?

User input would just need to be a simple pot for the overall speed - this would set the amount of foil fed in the window provided by the start/stop signals.

[Davek0974]

Yes but inexpensive until it comes to finding a plc capable of stepper control, although i must admit i have only used the larger more expensive units in the past - do you know of a cheaper PLC?

[Gary]

http://www.zappautomation.co.uk/elec...nit-23609.html
Its the last one, so once gone the price goes up.
if you want to set the speed from a 0-10V, you will need another plc, but you can set the speed in the program.
If you have not programmed plcs before you are best getting someone who has to commission the system.
I know an engineer who can do this, but he will charge you.

[Gary]

Also if you want to add a HMI so you can set the speed and move distance from a touch screen you can also do that with one of the HMI we sell.

[Davek0974]

Thanks Gary that looks a nice little unit but yes we will need to vary the speed somehow. The HMI is a good thought but is really not needed here, a simple pot will do the job, especially as the HMI really pushes the cost up.

[Gary]

Ok good luck, but if you are using a simple speed control. then you may have issues with it stalling if you set the speed too high and just enable it.
We also have a stepper driver that can run with a +/-10V or 0-10V and has limit inputs and a number of other features as well.

http://www.zappautomation.co.uk/elec...60-aa-000.html


or if you want closed loop and +/-10V like a servo.

http://www.zappautomation.co.uk/elec...or-driver.html

Thanks Gary that looks a nice little unit but yes we will need to vary the speed somehow. The HMI is a good thought but is really not needed here, a simple pot will do the job, especially as the HMI really pushes the cost up.

[Davek0974]

Thanks, i'll keep looking for the right solution. A simple speed control won't work - it needs to ramp up and down, this is the bit that makes it more complicated.