Bridgeport VMC760 retrofit

Ah using Linux to entirely tune the feedback loop?

I am interested in Ethercat communication, but I am getting slightly cold feet as it appears to be a path far less travelled in this forum.

Am I right in thinking that if you run analog signal and rely on linuxcnc to close the loop, all tuning happens within Linux, as per your link?

No auto tuning through the drives etc?

Thanks tommylight.

Thanks Tommylight.

I had a good read through your tutorial last night. Very informative.

Unfortunately it's the servo drives that are busted in my machine. I assume the procedure is similar for newer drives if running analog? I would tune the velocity/torque in the drive software, then tune position through Linuxcnc.

It looks like a few of the modern servo drives I've looked at have encoder outputs. Those will just run back into a Mesa card like the 7I97?

Hi Langdons,

Yeah definitely affordable!

We run 415v 3ph in Australia. Weirdly enough there isn't a huge amount of aliexpress drives that cater to that voltage.
Inovance, Leadshine and Delta do however offer 400v stuff which is nice.

tommylight wrote:

spincycle wrote:

I assume the procedure is similar for newer drives if running analog?
Yes.

spincycle wrote:

I would tune the velocity/torque in the drive software, then tune position through Linuxcnc.

Yes.

spincycle wrote:

It looks like a few of the modern servo drives I've looked at have encoder outputs. Those will just run back into a Mesa card like the 7I97?
Yes.
3 for 3, nice!
New drives can also be controlled by step/dir and also have encoder outputs, and those can again be used in LinuxCNC.
And there are several boards from Mesa that can be used, not just 7i97, a lot of combos there so when you are ready to order stuff, ask here first as we have the Mesa Master with us here, always, in the form of PCW.

Ace! Thanks Tommylight.

I have a 7i96 kicking around from a machine that never got off the ground, but I assume the lack of encoder inputs means I should use a different card.

This machine originally had rapids of 32,000mm/min with 16mm pitch ballscrews - 2000rpm on the axis. Would there be any benefit of analog over step/dir or even ethercat, to maintain such rates of speed and precision?

I just got off a 10hr flight. I took the original Bridgeport machine schematics with me to asses the control side of things. It looks like the Heidenhain output a 24v (sourcing?) signal to a bank of relays to control the solenoids, enables, mag motors, contractors etc. I assume a Mesa card, like the 7i84U could take this role?

It'd be bloody awesome if I could just retain these original distribution/control boards and halve the amount of wiring required!

langdons wrote:

Whoa, hold up.

Households in Austrailia use 415VAC?!

(little kid): "Hey daddy, what's this? ...kzapp! [kid gets electrocuted]"


 

Haha, I wish.

Some have 415 3ph, but normally we just have 240v single in houses. Most single phase outlets here limited to 15amp, even in industrial settings (high amp ones do exist, but aren't as common as high amp 415 3ph). Hence, I'll need 400v 3ph drives as that's the high amp I have available in the shop.

Alright.
Based on my research from the last couple of weeks, I've come up with the following plan and list of hardware for the retrofit.

Servos
Replace the dead 611 Simodrive system and associated axis motors. (I would like to reuse the Siemens motors, but refitting the encoders looks like a headache at this stage)
I'm looking at the Leadshine EL7 drives and associated motors. These come in 380v 3ph. Documentation seems good and the prices aren't bad direct from Leadshine.
Run these in via analog +-10v signal. Position feedback via Linuxcnc. Ideally run battery box encoder cables to keep position even when powered off.

Spindle
Retain the original 9/11kw spindle motor. I'll test the poles on it when I'm back, but I see no reason to not reuse it.
I've already got a good deal on a used Delta VFD110E43A. Paid less than 20% of a new one.
I'll have to get a braking resistor for this.
Run the original spindle encoder (or replace it) back to Linuxcnc for rigid tapping and spindle orientation.

Control
Looking at the following Mesa boards:
7i97T to handle analog control of servo drives, spindle VFD and all encoder feedback. Some I/O.
7i84 to handle additional I/O. Tap into the original Bridgeport relay boards to control tool mag, air solenoids etc.
7i73 to handle control panel keys, rotary encoders, MPG etc.
Coofun CK41 Celeron J4125 mini PC 
27" ELO touchscreen (got a lead on a cheap one here, might be a little big though)
A few panel buttons, MPG and rotary encoders for the interface.
GMOCCAPY looks like a great choice and reminds me of the Heidenhain control, which I've really learnt to love. I wish my Fanuc machine was more like it!

Other than the drives, vfd and front interface, the plan is to retain as much of the original control and wiring as possible. As previously mentioned, it doesn't look too hard to tap into the original I/O feeds from the Heidenhain. I also spent some time earlier in the year replacing all the capacitive snubbers on these control boards (with ones that don't light themselves on fire!) Fresh contractors in some spots as well.

Retain all the original breakers and transformers. There is a large contactor, breaker and transformer (415 to 380v) for the servo drives which I'd very much like to reuse (and not rewire!)

Let me now if any of this sounds entirely wrong or you have better ideas on how to execute. While I've played with cnc machines for a while now, this will be a my first experience with Linuxcnc feedback loop on servos/spindle and controlling a tool changer. 

Many thanks,

J