Stepper vs. Servo Question for Turning Center

John, what does "field power transformer" mean? I do have two DIN rail mounting 24VDC switching power supplies. Does that help? If so, I'm in pretty good shape, as the only thing I really need to purchase are the servo motors, encoders, and Mesa cards.

BigJohnT wrote:

The 7i77 needs a 24vdc power supply for the I/O and the sserial to work. The DIN rail power supply should work. What is the watt rating of the power supply? Not that you need much for switches and proxes and stuff like that. The 5v from the cable should power the two encoders and a MPG if not a 5vdc power supply can be used. JT

John, I don't know the wattage of one of them. It's heftier than the other, so I'm ASSUMING I am safe. The two I have are -

Phoenix Contact CM 62-PS-120AC/24DC/1
One like it can be seen here - POWER SUPPLY or HERE

and

Omega DRN-PS-1000 24VDC @ 850mA Max 20Watts Power Supply. Manual ( PDF ) can be viewed HERE

Which one would be better for me?

As an aside, I just checked and one of the old transformers I kept when upgrading some other equipment will be perfect for my servo amp power supply. The motors are rated 60VDC and this transformer is tapped 380, 277, & 208 on the primary side and 115 & 95 on the secondary side. So if I use the 277 taps with 120VAC, the 95 taps will yield me 41.16VAC that I can rectify into 58.19VDC for the servos. I believe I have enough here to build the rectifier, as well... so it looks like I have most of the hard stuff already taken care of. ( famous last words )

Do all my button switches and the MPG connect directly to the 5i25/7i77?

Thanks for the assistance, boys.

BigJohnT wrote:

The Phoenix is 1 amp so that should be plenty for all your I/O.
Yes, all the I/O, encoders, MPG, velocity (to drives), enable... everything really is connect to the 7i77. There is a cable between the 5i25 and the 7i77.
JT

Thank you, John. ( or do you prefer JT? )

I wish I could find someone that has been here, before. Would really help for things like knowing if I will need to use a second power supply for the tool turret or will this one suffice by itself? Or is that what you were talking about, above?

I recall Peter's post referencing this and really need to try and figure this part out...

... just don't call you late for dinner, though. Right? Thank you for the help. Looks like I'll be ordering tomorrow.

Simply for posterity's sake, should someone try searching for it in the future, someone directed me to an old
thread on the Yahoo group that centers around these Emco machines, and mentions the steppers ratings and set up.

Quote -

"The spec sheet quotes 2000N of axis force. If we take the rated stepper torque
of 120Ncm x 0.7 for torque lost due to half stepping, the gearing, and screw
lead we arrive at 2000N. The 1200mm/min also seems to keep the original steppers
within the RPM that provides maximum torque. It appears that these were running
at 2.5 micron resolution. That's .0001". BTW, 400ozin steppers at 10x will
result in twice the resolution, but half the torque as the original setup. 5x
would be identical."

Hopefully someone can use that info in the future.
And if so, and it's sufficiently far enough into the future, send back a pepperoni pizza and some beer!