Thermo Scientific Oretronic III, Operating & Service Manual

Page: 85 / 152

Maintaining & Troubleshooting
Thermo Fisher Scientific Maintaining & Troubleshooting 4-17
REC-4105 Rev L
If the CLP FINE value reaches 500 and false trips are still occurring,
scroll to the CLP CORS display and repeat this procedure from Step
10.
There are a number of reasons why the TMD may pass tramp
undetected. The detector may be incorrectly wired or installed, the
metal sensitivity number may be too low, the size of the tramp may be
too small for the coil size and separation, the coils, or junction box may
be damaged, or the TMD may be malfunctioning.
Tramp may also pass undetected if your system uses clip detection and
the size of the clip(s) is large compared to the size of the tramp you are
trying to detect. If there should happen to be tramp metal on top of a
clip, the TMD may not detect the metal because it is letting the clip pass.
If your TMD is passing tramp undetected, use the procedures in this
section to help determine the cause. The procedures are written as
though you are familiar with using the operator interface. If you are not
familiar with the operator interface, please read the detailed descriptions
of the front panel keys, indicators, and displays in Chapter 3 of this
manual before beginning any of these procedures.
The most common cause of undetected tramp is having the metal
sensitivity setting too low for the tramp you are trying to detect.
Whenever you calibrate the TMD for tramp metal, make sure you use
the same size, shape, and type of metal for the calibration that you
expect to trip the detector during normal operation.
The TMD is designed so that when it is auto-calibrated, the threshold for
a trip is just slightly less than the signal seen when the metal was passed
during the calibration. A small irregularity in the shape of the tramp or a
variation in placement between the coils will result in a slightly different
strength signal. For these reasons, a round ball gives the most consistent
calibration results. Even using a ball for calibration, however, the metal
threshold value may vary a few digits from calibration to calibration.
Follow this procedure to adjust the metal sensitivity of the TMD.
1. Perform an auto-calibration for both coarse and fine metal
sensitivity as described in Section “Initial Setup Procedure”.
2. Place the TMD in Run mode and pass the test tramp through the
coils in the normal direction of travel.
Passing
Tramp
Undetected
Adjusting Metal
Sensitivity