[multiplex]

putting together some parts to convert my router table from steppers to servo. First step is to covert the Y axis, and see how that goes before moving on to the others.

I currently drive the gantry with two steppers for the Y. Easy enough, as Mach handles slaving the drives.

my concern is if there is an error on one drive, how do i shut down the other?

with steppers, they obviously just stall.. but not sure that would happen with the servos

[Larken]

If you gang all the Fault output lines on the Vipers together and tie to the Reset input on Mach, the system should stop when you have a fault.

Is it a viper 95 or 200 ?

Larry K

[multiplex]

ok getting a little closer to making things happen.

Drives are setup, and I'm testing one motor on the bench - tuning PID.

These are 60v nema 23 motors from Keling.

I'm currently powering them with a 38v power supply.

I seem to be getting more overshoot than I'd like to see. Could this be at all related to not having enough voltage?

The stiffness of the motor is still a little low, and i have the P = 1000. D = 2000, i = 10, l=4

The motor is stable, but overshoots.

Just not sure what direction to go

Thanks!

[Larken]

I use those motors on our small routers. I've found the L setting should be 2 or 3.

What encoder resolution do you have ?

On the bench do you have a pulley on the shaft or a load ?

The only time i've seen overshoot is when the motor is too small for the load, or deceleration is really fast with a big load.

Do you mean over-shoot or oscillation ?

Larry K

[multiplex]

I'm using a 500 count encoder, and currently have 4 step multiplier. I'm most likely going to set this to 8, so that it reduces the load on my PC. I'm shooting for around 300IPM.

Currently i have the motor on the bench with a 2" diameter pulley on it - unloaded.

Next step will be to hook the motor up to the screw (4:1 reduction) and drive the gantry with just one motor, disconnecting the second screw. I wasn't sure if I was ready for that yet.

But maybe the extra load will help with the overshoot?

yeah it seems to be overshoot, and not oscillation. Maybe my acceleration is too fast. I'll check it out tomorrow

I was pretty happy to get these wired up, and working within a few hours

Once i prove out the Y axis, i'm going to implement the X and Z.

Side question - what is the purpose of the test position, verses program 1,2 or 3.

[multiplex]

also would you mind sharing your PID values? or possibly pointing me in the right direction?

thanks