This document summarizes work done to resolve issues with a saw. It describes leveling the saw table, machining a new mounting plate to align the roller conveyor, replacing a faulty PLC controller battery, downloading a new program to correct registry values, and fixing a loose wire in a connector causing servo errors. The longstanding issue of the saw cutting short on the first piece was resolved by updating an incorrect registry value of 0.100 inches.

1. Project Lead: Eric Mosley
Assistant: Michael Logan
December 2013

2. • Roller Conveyor not aligned with saw table.
• Saw table was not trammed. (square in all axies)
• Saw was down.
Due to:
• Electronic issues.
• Software issues.
• Wiring issues.
• Firmware issues.
• Mechanical issues.

3. BEFORE AFTER
This was resolved by levelling the saw and machining a new
improved mount plate for the roller table.

4. Machined a new mounting plate
that would allow the conveyor
structure to be adjusted higher, so
that the roller could be leveled with
saw table top.
New mount plate allowing roller height to be
increased where previously it could not be.

5. BEFORE AFTER
Resolved by rotating the machine and locking its position.

6. Catastrophic issues with machine across the board.
At Power up the screen would display we had a
catastrophic error. (image on the right)
My attempts to clear the errors were
successful by reprogramming the CTC registry
file. (e-stop was still an issue) But once power was
cycled, all data / program was lost.
Resulting in the same error screen at each
machine power on/restart.
The issue was caused by a bad CTC
(PLC CPU) according to Joseph Machine.
They said we would need a new CTC at the cost
of $3700.00.
The CTC was repairable but expensive and we
would be down a minimum 3-4 weeks to wait
on repairs.

7. Replaced old battery with secured new battery.
I decided that the
issue must be with
the CMOS battery
being dead and that
replacement of the
battery would solve the
issue of data loss on power cycles.
After removal and disassembly of
the CTC I found the battery I had
assumed was the issue.

8. Downloaded new Program and Corrected Registry values.
After installation of the repaired CTC
unit, I reprogrammed the registry,
cycled the power and no data loss
accrued. Problem solved.
At start up I still had an error screen for
the e-stop. I later found that the PLC
program also resides on the same non-
flash memory as the Registry. I then
verified the correct PLC program and
downloaded it to the plc controller.
Cycled power and found no software
errors.

9. After pushing the pin(1) out of the Molex(2)
connector I found the wire(3) was not clamped to
the pin(1) at all.
I made the obvious repair here which fixed the servo
error issue for good.
After reviewing the machines schematics, I found that
the probable cause was between the CTC and Servo
Amp. After further investigation I found the signal wire
from the CTC was in the interface jack but was not
making good contact inside the Molex plug.
Saw was experiencing random episodes of errors in regards to the servo resulting in machine down scenario.
Bad wiring causing intermittent servo errors.

10. After reviewing the standard registry values, I found
one value to contain the incorrect value of .100”
that turned out to be the culprit. After updating this
value the issue immediately disappeared.
“The saw has had issues for years where it would cut the
first pc in every cycle after the 1st cycle .100” short.
We had them work on it but they couldn’t ever figure it
out” (Elvin Mills) Senior Maint. Supervisor.
In the past maintenance would try tightening or
loosening the drive belt tensioner in hopes to remove
backlash or tweak things which would provide very little
help.
Operators would then fudge the parts nominal length
when inputting to the saws length value.
Between these two operations one could get the bad 1st
parts and good parts to fall with-in side of the full +/-
tolerance range. However it was extremely risky as these
tolerances were borderline, more than not.
Issue that has long plagued the saw.
What was once thought to be a mechanical issue.