4. Disconnect the readhead brackets and run the problematic readhead back and forth along the scale
track by hand (much like a "Hot Wheels" car). Just to make sure, try running the readhead in both
directions (ie cable to the left, and then cable to the right) to see if the display suddenly starts working. If
this "fixes" the problem, then the issue was most likely an improper gap between the readhead and the
scale. The proper gap is 0.5mm, or 20 thousands, and should be set using the included shim that came
with your kit. An improper gap could have been caused by either the readhead, or the scale being
bumped or jarred out of alignment. It may be a sudden causation, such as a workpiece or tool striking the
bracketry, or something much less insidiuous, such as moving full travel down a scale that was improperly
installed and always mis-aligned, but was never "found out" because the operator never went full travel
on the scale. In any case, if the scale is not reading correctly, make sure to perform the following steps in
order:
I. First check to make sure the scale is level. Run a dial indicator along the top and the side of the
scale,
full travel
,
both directions
.
II. Check the readhead for physical damage. A readhead can be crushed with very little apparent
external visible damage.
III. Make sure the wipers (and wiper holders) are installed correctly. The bevel on the black
plastic wiper holder block should be pointed
away
from the scale, not towards it.
IV. Check the gap between the readhead and the scale. The proper gap is 0.5mm, or 20
thousands, and should be set using the included shim that came with your kit.
Make sure to check the gap all along the scale, especially at full travel, on both ends of the scale. Do not
simply check the gap at one location and call it good. Make sure the gap between the readhead and the
scale is consistent along the
entire full travel of the scale
.
If the scale still seems to be mis-reading, try resetting the display to it's original factory settings (see the
DRO PROS Library page for the appropriate document).
If all the above fails, or you simply get confused as to what is happening, give us a call. We're here to
help, and have dealt with the above scenarios many times.
