Strain Gage Reaction Torquemeters Installation Guide
S. Himmelstein and Company
© 2017 S. Himmelstein and Company—all rights reserved www.himmelstein.com
7
B.7 Calibration Function
These Torquemeters have a remotely initiated bi-polar
calibration check. The Calibration Signal produced in
response to a Cal Command is referenced to the factory
dead weight torque calibration and, is NIST traceable.
Thus, when invoked, it permits calibration of the users’ data
acquisition system, traceable to NIST. Furthermore, because
it is bidirectional, it verifies operation of the data chain in
both the CW and CCW directions. Bi-polar calibrations
may be invoked from your PC using the supplied interface
software. Alternately you can invoke a positive calibration
as follows:
For Positive (CW) Calibration: ground Pin 1 to Pin 8. The
calibration signal will remain on until the short is released.
A Calibration command should only be invoked while
the driveline torque is at zero; if locked-in torque is present,
break a shaft coupling to reduce it to zero. Always remove
the Cal Check command before running a test.
Equivalent calibration values, in engineering units of
measure, are listed on the Calibration Certificate which doc-
uments NIST traceability*. They can also be accessed using
the furnished software. Calibration values are determined
in S. Himmelstein and Company’s accredited* (NVLAP
Lab Code 200487-0) calibration laboratory. The user may
perform a dead weight calibration and store the results in
memory, using furnished software. The original cal data is
archived. Before performing a field dead weight calibration
please read and understand Paragraphs C.5 and C.6.
*For details visit www.himmelstein.com or follow the
accreditation link at www.nist.gov.
B.8 Clockwise (CW) and Counterclockwise (CCW) Definition
CW torque causes the shaft to turn CW when viewed from the
driven end. CCW torque causes the opposite rotation. Himmelstein
uses the following polarity definitions:
By default, CW Torque applied to the Torquemeter
produces a positive output signal, CCW torque applied to
the Torquemeter produces a negative output signal. The
Torque signal polarity may be changed using the furnished
software.
B.9 Tare Function
The Tare function is intended to cancel or “zero” a torque value
that is not due to a permanent shift in the Torquemeter itself. For
example, if you are interested in seeing the result of a gear shift
you can Tare the running Torque before the shift and then see the
resultant shift torque.
Caution: Unless you remove the Tare Value, by using the
Clear Tare function (or cycling power off/on), subsequent
readings will be in error due to the residual Tare. Tare values
are deleted when power is turned off. The Tare and Clear Tare
functions can be invoked from a remote PC with the software
furnished. The Tare function can also be invoked by driving a
control pin, as follows:
Invoke Tare by grounding Pin 6 to Pin 8. Then, remove the
ground.
Please note, the Torque signal will be zeroed (or Tared) as long
as the Tare command is invoked.
B.10 Torque Zeroing
The Zero function is intended to correct a minor long term drift
or slight yield in the Torquemeter itself. TORQUE ZEROING
SHOULD ONLY BE DONE WHEN THE DRIVELINE TORQUE
IS ZERO. If locked-in torque is present, break a shaft coupling
to remove it before attempting to Zero the Torquemeter. Should
the Torquemeter Zero shift by more than 1% of the Torqueme-
ter Full Scale Rating, return the Torquemeter to the factory for
re-calibration and/or service, if indicated. Zero adjustments
are retained during power off and automatically accessed when
power is re-applied.
The Zero function can be accessed using the supplied software
or, by simultaneously grounding Pins 1 and 6 to Pin 8.
B.11 Re-setting Max/Mins
Is accomplished via the supplied interface software or, by cycling
power off/on. Max/Min values are only available on the digital
output.
B.12 Digital Output
When connecting to a PC using the supplied interface software, the
following torque data will be displayed along with the Engineering
Unit of Measure selected (default is lbf-in)
•
current data
•
maximum torque since last re-set
•
minimum torque since last re-set
•
torque spread (maximum - minimum)
Additionally, a Torque vs Time plot will be displayed with user
control of both axis.
B.13 Analog Output
The analog output appears between pins 5 and 3 and reflects
current data only. Its’ default value is 10.000V at Torquemeter full
scale. It may be reset to a lower value. It is linear to 150% (Over-
range) or 15V.
