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Connecting a servo driver
« on: October 10, 2020, 05:24:01 AM »
I hope someone can help with servo driver connections.
My cnc lathe has Fagor servo drivers, and closed loop encodes with the service motors.

The servo driver board has 3 connections, each with a + and - leg.

I want to connect this board to my Mach3 driven breakout board, but don't know which connections are for direction and which for step.

The three connections are : command, limit, and enable.
I could assume comand is the step connection, and enable the direction connection.
Would you agree? (Before I break something).

Many thanks


Offline Graham Waterworth

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Re: Connecting a servo driver
« Reply #1 on: October 10, 2020, 06:13:25 PM »
A lot of servo drives are +-10V analogue so mach3/4 can not drive them without a motion controller that can do this.

You need to look up the board you have to see if it is analogue.

Without engineers the world stops
Re: Connecting a servo driver
« Reply #2 on: October 11, 2020, 04:51:20 AM »
Looking at the cnc output wiring the cables designated X and Z outputs carry a 5 volt output in a square wave form, so I guess not analogue.

The cables are quite tricky to follow, making their way through some din mounted " double decker" connectors, and 11 relays of which 9 are limit switches and cut outs.

Some of the connectors are well dodgey and intermittent. I want to replace the lot now, and as I use Mach3 on my cnc mill this seems the best way to go.

Any more suggestions welcomed,


Re: Connecting a servo driver
« Reply #3 on: October 13, 2020, 05:40:28 AM »
Yesterday I spent many happy hours laying on my front tracing wires.
The steps are entered into the Command connection.
Direction is one wire to Enable minus.
Limit - I haven't worked this out yet - but it feeds the +5v to the other enable side.

Just waiting to have some multi core wire delivered and then we will see if it works!"


Offline BR549

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Re: Connecting a servo driver
« Reply #4 on: October 13, 2020, 04:25:35 PM »
HUM, I do not recall ANY fagor drives being step/direction they were all analog. What is the part number of the drives ?

You really need to look up the drives to see what control they actually use . It would be very easy to let all the good smoke out of the drives if you are not carefull.

(;-) TP
« Last Edit: October 13, 2020, 04:27:55 PM by BR549 »
Re: Connecting a servo driver
« Reply #5 on: October 13, 2020, 04:33:56 PM »

I cant see what the fagor driver is yet, but I plan to take it out on Thursday (not visibly an easy job!) and will post the result then.

Hopefully I be able to spot the encoder connections then as well.

Re: Connecting a servo driver
« Reply #6 on: October 14, 2020, 06:07:24 AM »
OK so I have extracted the Servo Driver now.

It consists of a largish connecting module/housing and two driver cards - one for each axis.
there are no makers references on the housing, and the only markers on the driver boards are "LPE 192".

Does this ring any bells with anyone please?

Many thanks.