Originally Posted by
dracozny
Plenty of users have used glass scales without any complaints. As long as they are mounted in a solid level position so that chips cannot get into them you should be fine. Things that will kill your accuracy in these scales is improper mounting, chips getting into the encoder reader, and electrical noise. So make sure you have good grounding between the machine and the cable conduits. Use of an ohm meter across grounded points is imperative.
Given your experience level here, I am sure you will have no problems.
The main thing is, if you decide to run these directly to the controller, from what I have read you will not want to rely on them for commutation but for reference only. so you may find yourself using two sets of encoders, rotory on the motors or ball screws and then the linear on the table. JimDawson over at the other forum may have some insights on this since he runs some very expensive magnetic linear encoders from England on his machine for position feedback to the controller.