MTS SWIFT 20 Ultra Sensor - Manual (Page 135)

SWIFT 20 Sensors Troubleshooting 135
Shunt Calibration indicator
light blinks after shunt
calibration indicating
Shunt Calibration failed
(continued). The shunt reference values
were changed. Use the TIXFER utility to upload the current
calibration file. Check the file to verify that the
variables ShuntDeltaRef are the same as shown
on the original calibration file provided by
MTS. The eight ShuntDeltaMeas values
should read approximately the same for all eight
bridges.
The shunt tolerance is not
set correctly. Use the TIXFER utility to upload the current
calibration file. The ShuntTolerance value
should be set at 2, indicating an allowable shunt
variation of 2%. If this value is changed to zero
or a very small number, the difference between
the reference and the current shunt
measurement may fall outside of this tolerance
and be read as a shunt failure.
Shunt cable problems. If the ShuntDeltaMeas values are not the same
as (or within tolerance of the ShuntDeltaRef
values), note which shunt values are not the
same.
If all eight are not correct, check the shunt
cables, signal cable, and power supply.
If four of the signals are not correct, verify that
both shunt cables are plugged in and are not
damaged. (Each shunt cable shunts four
bridges). If connections appear correct, swap
the shunt cables at both the TI and transducer
connections, and check whether the bad shunt
values follow the cable. This indicates a
damaged or faulty cable. Check that the cable is
not damaged, and that connector pins are not
missing or damaged.
Use the same swapping technique if one or
more signals is not correct. In this case, note
which bridge has the different value. If the
faulty shunt value stays the same with the cable
swap, look at the transducer shunt connectors
for damage or objects plugging the connector
and contact MTS.
Make sure the two shunt cables are connected to
the proper places (A to 1, B to 2).
Shunt Calibration as
Recorded by External Data
Acquisition is incorrect or
inconsistent. (The internal
shunt check in the TI
electronics verifies each of
the eight individual
bridges, but it is the six
bridge 10 V output that you
can record if desired.) The AngleMode and
FixedAngle are not set
correctly, so an angular
transformation is changing
six bridge outputs as a result
of the eight shunted bridge
outputs depending on the
angle of the transducer. Using the TIXFER utility, verify that the
AngleMode is set to 1 and the FixedAngle is
set to 0 during shunt calibrations that will be
recorded externally. This does not need to be
done for the internal TI Electronics shunt
procedure, but may be needed to remove the
angular dependency of the shunt outputs on the
six bridge 10 V outputs. (This restriction may
disappear in the future)
Troubleshooting Guide (part 9 of 14)
Symptom Possible Causes Solution