Wiring of servo spindle - MESA 7i76E

Hi All,

I was hoping somebody could point me in the right direction regarding my wiring for my servo spindle to a MESA 7I76E.
I bought a 2.2 kW servo spindle from China.

As I am quite new to all of this, it would be great if somebody could tell me if my wiring is (so far) correct and maybe fill in the gaps.

I am a little confused that there are not 2 inputs for SPINDLE DIR + and - on the servo.

I was also wondering if the TB4- Pin3 SPINDLE+ needs an exact 10 V supply or if a 12 V would be fine.
Any help would be very much appreciated.

This is the last little bit of my control box that I have to sort out.

Many thanks!!!

The 7I76E spindle enable and direction outputs are switches so both leads must be used:

ENA- 24V GND
ENA+ Drive Speed Enable
DIR- 24V GND
DIR+ Drive Reverse

12V is OK, 16V is absolute max

Excellent - Thank you very much that was very helpful.

As ENA+/- and DIR+/- operate as switches would that mean I could switch the suggested connections around.

I revised the wiring diagram. Does that look right to you?

I have a few more questions if you don't mind:

• SEL needs to be connected to 24V DC - correct?
• Where should I connect the Emergency Stop to?
• What does DO COM stand for and where should I connect this one to (TB6 - PIN1 INPUT 0)?
• Are Warn Output, Speed Reach, Zero Speed of any use for LinuxCNC and if yes where should I send them back to on the MESA board?
• Is the connections OZ+ to IDX- and OZ- to IDX+ correct? Or do they need to be swapped around?

Thank you!

The diagram looks correct

I suspect DO COM either goes to ground of +24V but this needs to be checked in the
drive manua.l How this is connected will determine how easy is will be to use the
Warn Output, Speed Reach, Zero Speed outputs. Note that Speed Reach and Zero Speed
can be sensed by LinuxCNC with the encoder feedback.

Typically the IDX polarity is "dont care" because it only determines the active edge of the
index so on normal encoders only makes a 1 count difference.

Emergency stop would be connected to your emergency stop loop (it should disable the drive when open)
This loop consists of series contacts will normally have at least mechanical Estop switch plus perhaps a
relay under LinuxCNC control.

Thank you PCW.

I had a look in the manual and I attached the page that concerns the wiring for SEL and OCOM. Could you please have a look?!
From what I gather both ports would need to be connected to an external 24V?! 
Is it better to take the 24V from the MESA board directly (as they have a current limit I believe) or from my 24 power supply?
So how would I connect the Warn Out and the Speed Reach and Zero Speed to the MESA board. I guess the Warn Out would be quite useful.

I can wire the emergency stop of the spindle drive into my 'emergency stop circuit' - no problem. However, a contactor in the emergency loop would already switch off the power to the spindle drive in case of an emergency stop. So would there be any point? I believe you might need it for operation though.

Is it advisable to have a software emergency stop from Linux CNC breaking the physical emergency stop loop via a relay? Currently I don't have that. Currently, I only have an emergency stop on the control box and on my pendant that is connected to this emergency loop.
In case it is a good idea, do you have any specific suggestions for such a relay? Something like this: www.digikey.com.au/en/products/detail/we...r/1218390000/5996986 

Thank you again -  I am almost there 

Yes, with OCOM connected to +24V you can wire the status outputs directly to
7I76E inputs.

The advantage of including LinuxCNC in the Estop loop is that a linuxCNC detected fault
can shut the system down

I don't think I want to give specific Estop recommendations.

I just came across another issue regarding the emergency stop for the spindle server.

I have the emergency stop loop on a dedicated 24V DC power supply. The 24V DC that goes to the Servo Drive comes from a dedicated MESA power supply.

I believe that means that I would need to use a relay that is controlled by the emergency stop loop to switch the MESA 24V line (which is going to the emergency stop input of the servo drive)? Is this correct - there is no other/simpler way?

I don't need any recommendation only try to get an understanding. 

To incude LinucCNC in the EStop control loop,
you could drive a relay from a 7I76E output

The relay can switch the EStop loop 24V

This was very helpful thank you and I got the emergency control loop linked with mesa now.

I have two questions remaining:

1. My spindle takes an input 24 V signal at the emergency stop port to go into an emergency stop mode.
My question is as I am cutting at the same time the power via my emergency stop loop and a contactor to the spindle this emergency stop input at the drive becomes a little pointless?
Do you agree? Why is it there in the first place?

2. Finally, how would I use the Warn Output, Speed Reach, Zero Speed output signals from the servo driver in my mesa system/linux cnc software?

Sorry I believe that these are some very basic questions but it is hard to find the answers in any manuals.

Cheers

1. It's there because the drive manufacturer has no idea what estop scheme, if any, is being created by the machine builder.  The drive manufacturer adds an internal 'estop' or 'safe-torque-off' type function to make it easier for the machine builder to integrate.

In some cases it is preferable to stop a device by cutting the bus power but leaving the control/logic power enabled.  In others, you want a controlled stop where the device or controller will use main bus power to slow the spindle/motor as fast as possible and then turn off.  It's up to the machine builder/integrator (you) to determine what you want to happen under difference circumstances, and what regulations you're obliged to follow in your jurisdiction regarding safety-type systems.

You might consider using the spindle drive's internal 'estop' function as a secondary 'spindle-inhibit'.  If you want to work on the machine with the spindle disabled you don't necessarily want to estop it and lose offsets.  If you had a manual switch not connected to LCNC which killed the drive but didn't shut everything down, you could use that when reaching in the machine (or even changing a tool) without the 'nuclear-option' estop.

2. I assume those are programmable digital outputs from the drive.  It's up to you what you want to do with them, but if you are running the spindle/drive open loop (no encoder signal to mesa/LCNC), you could connect those outputs to mesa inputs.  Then connect the mesa inputs in HAL to:

- motion.spindle.0.at-speed (stops machine from moving until spindle is at speed.  Probably want some sort of RPM tolerance window, there are plenty of examples of actual working configs on the forum) 

- zero speed could be connected to a power draw-bar enable function.  i.e. a manual button is pressed, but the drawbar can't activate unless the zero-speed input is also active.

- not sure what Warn Output does.  Would need to read the manual before speculating on how/if to use it in LCNC.