What would you guy's recommend for encoders?

I have an cnc knee mill with sem servo motors and just bought some AMC servo drives to replace the original ones. The mill has tachs on the motors and A10 linear scales, would you guys recommend using the linear encoders or should I ad an encoder on each motor instead, just want what be best.
Any input on this would be greatly appreciated.
Thanks Mike

if the drives support tachometer input and velocity mode then I would use that and close the position loop with the linear scales. In theory that gives the best accuracy.

Yes they do support tachometer input, thank you for your help.

I would keep the linear encoders on the X and Y. Is this for the anilam project you posted on before?
If so, you need to understand that the ball screws on the older machines were not super high precision and positional accuracy was achieved with the linear encoders. I was reminded of that by an Anilam repair specialist.
If you have rotary encoder on the Z ball screw, I would replace that with a US-digital product. I used one that happen to be a direct fit with higher resolution. I can look for the part number if you're interested.
To get it going, I would try to use the boards in the machine as previously suggested if they still work and read in the encoder to a 7i77 etc.

Yes it is for the anilam crusader m control. I don't know if the old drives work, and I have purchased new AMC drives that I would like to use.And yes to the z axis encoder info.
Thanks for your help.
Thanks Mike

The US Digital part number I used for the encoder: E5-1000-250-IE-D-D-G-B (1000 cpr with 1/4 bore)
Cable: CA-FC10-SH-NC-15 (Connector one end)

This is on my mill:

Awesome, and thanks.

Can anyone tell me what this is in the drawing that's circled.
Thanks Mike

That and the switch drawn beside it are a relay. You've circled the relay coil (low voltage side)

OK thank you, but is it really necessary to have a relay there, I wasn't planning on putting one in.
Thanks Mike