MTS SWIFT 30 Sensor - Manual (Page 130)

SWIFT 30 Sensors 130 Troubleshooting
Zero Offset: One or more
Signal Outputs appears to
have a zero offset after the
TI electronics have been
zeroed. The transducer was zeroed
with load applied (or a
different load than the
intended tare weight for
non-spinning applications
only).
Rezero the TI, being careful not to touch or load
the transducer during the zeroing procedure.
Rotate the wheel by contacting only the inner
diameter of the SWIFT sensor, the hub adapter,
or the opposite wheel while gears are engaged.
TI was not warmed up
before zeroing.
Verify that the TI was powered on for at least
five minutes before zeroing.
Considerable temperature
changes have occurred. The SWIFT transducer is temperature-
compensated to reduce temperature-induced
errors, but any significant changes in
temperature will induce zero shifts. For best
results, zeroing should occur at the conditions
closest to those of the test conditions.
The tire rotation was not
continuous or smooth. The tire should be rotated at a slow and constant
velocity. Changes in acceleration or jerkiness
can produce inertial loads which will affect
bridge zeroes.
If the tire is rotated in one direction for part of
the time, any small rotation in the other
direction will cause bridge zero and angle errors
in the spinning zero mode.
Noise in the system. Noise in the power supply or high magnetic
fields can cause errors in the zeroes. For more
information, see grounding suggestions in
“Installing the Transducer.”
Zero button was pressed
with cables not connected,
or during a loaded test
If the Zero button is pressed with the cables not
connected, the TI Electronics will set the new
zero values according to this zero voltage
signal. If the Zero button is accidentally pressed
during a test, the TI electronics will zero the
bridges at whatever load they are reading at the
time the Zero button was pressed, resulting in
an erroneous bridge zero value.
The data acquisition
configuration or input ports
show a zero offset.
After zeroing, while the TI is turned on and all
cables from the SWIFT transducer to TI are
connected, use a handheld DVM to verify the
output of individual channels while they are
being loaded. (Use the BNC connectors located
on the back panel of the TI.) With no load
applied, the outputs should be 0 V. If the data
acquisition is showing an offset while the TI
reads 0 V (as measured by the handheld DVM),
the data acquisition is set up incorrectly, or is
inducing the offset.
Troubleshooting Guide (part 3 of 12)
S YMPTOM P OSSIBLE C AUSES S OLUTION