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I'm pretty sure there isn't a simple way to do it but thought I'd ask if anyone could have a quick double check for me as I've got a couple of sprint 340xri dc drives and if I can utilise the reversing function that would be great?

I know the "easy" option is just put a modern VFD and AC motor but I've got a couple of functional machines that don't really need a motor upgrade and the messing that goes with making them fit at the moment.

I could look at a signal converter but the only thing I have seen seems to be prohibitively expense ( best part of a VFD)

Sprint manual should be attached.

Funnily enough i am trying to work out if i can do exactly the same thing , so i wait with baited breath for your answers
I couldnt see your manual attached so ive hopfully added it to this post !

Just trying to clarify what it is that you are trying to do. As I understand it, you are trying to reverse the spindle. If this is the case, I had a similar issue using a GPIO4D with an Indramat DC drive. The drive accepted +10/-10 VDC. The GPIO4D only outputs direction and 0-10 VDC. I ended up using the direction output from the GPIO4D to energize a contactor to reverse the output leads from the drive to the motor. I didn't need to do anything to the field winding. Don't forget to use auxiliary contacts to also reverse the tach leads. I apologize if I didn't understand your issue.

Cheers for uploading the manuals, I'm using my phone and seemed to have attached but obviously didn't.

Yes the DC drive have a -10v to use for reversing, but there is more than one way to implement it, so if someone had already figured something...

We could use a relay but if its possible utilising the reversing that is built in to the drive with the spindle reverse output then that would be a lot neater and could use the built-in brake function and not have the risk of the opposite rotation being engaged too soon/motor being disconnected while still in motion.

Using a relay to invert the 0-10VDC input does NOT always work. I tried that sometime ago.
It requires inverting the 0-10VDC signal and utilizes a -15 0 +15 or similar power supply.
I made this request of CNC4PC and this is what they came up with:
https://www.cnc4pc.com/c89-10vdc-analog ... board.html

Personally, I think they over complicated it but the jist of it is, it will take the 0-10VDC analog input from Acorn and output the 0-10VDC signal.
When it sees a reverse signal, it will invert the output. It does this with logic on the board and DC-DC converters.

My suggestion is that you contact CNC4PC and ask.

Marty