The Beaver conversion to servo motors


#1

Hi!

I am posting here to check whether we are on the right path. The object is to modernise an old 1960’s Beaver Mill. We rescued it over ten years ago and computerised it by building new driver cards for the old unipolar steppers and controlling it with Mach3, but now, 10 years later, we would like to improve further.

Unipolar steppers have their issues and so does Mach3, especially on modern hardware. So the owner has bought three servo motors:

So this is what we intend to add:
Hardware
Three Granite Argon Cards
One SimpleMotion V2 USB adapter
One 24V PSU for logic Estop and brakes (how much power is needed?)
One computer

This takes care of the hardware bit. Does this bit sound OK?
Software
This is the tricky part. The easiest path is probably Mach4 pro, but LinuxCNC looks very tempting. Anyway, the setup above should work with either Mach4 or LinuxCNC, right?

Picture of the old Beaver mill:


#2

Hi Anders

Nice looking project!

Those servo motors looks to be very ideal to Argon.

Argon is specified at maximum of 0.5 A for the 24 V logic voltage, so you should be able to estimate the current needed from checking the motor brake current consumption. Also, it’s usually good practice to add some overhead to the PSU powre rating. This especially so if cheapest Chinese PSUs are used, as they tend to be overrated very often.

For the setup, I recommend you get also a good braking resistor and a simplemotion breakout board (SMV2BRK). The latter makes the termination and wiring a breeze.
https://granitedevices.com/wiki/SMV2BRK

Both Mach and linuxcnc will work well with your setup. Easiest being step/dir setpoint signal for which many interface cards are available.

Kind regards,
Esa


#3

OK. We will check the brake current and size the PSU accordingly. I tend to stay away from cheap no-name chinese PSUs and probably go for a MeanWell.

Both Mach and linuxcnc will work well with your setup. Easiest being step/dir setpoint signal for which many interface cards are available.

Can you elaborate? What signal?


#4

An additional question: We cannot find any mention of how much power the brake needs from 24V. I guess you can hook up a LAB PSU to the brake and measure?


#5

Hi, for brake power consumption, consider P=UI and I=U/R.


#6

OK. I realise that :slight_smile: So if the brake is a pure resistive device, then I could just measure the resistance and calculate the power from that. Right?


#7

Yeap. That’s what I meant. (You could lower the power consumption only by lowering the voltage.)