They make
setting up your electronics for the extensometer quick and
easy. For any strain gaged extensometer in the catalog, now
calibration with any electronics is easier than ever.
What
are they?
Shunt
calibration modules are a means of transferring Epsilon’s
transducer calibration to the electronics, so the output
reads correctly.
A very common method of calibrating electronics for
use with strain gaged transducers is through a process
known as shunt calibration. A resistor connected across
one arm of the sensor bridge causes the output to shift.
When properly chosen this resistor will simulate an
output whose value may be precisely measured and reported.
In order to set the electronics properly, it must read
zero when the extensometer is at zero. It also must
have the proper amplification (or output slope) so that
non-zero readings are correct. Two points are required
to accomplish this.
The Shunt Calibration Module works for any of Epsilon’s
strain gaged extensometers and with nearly any electronics.
As shown in the photo, the module is a simple plug in
device containing the shunt resistor. It plugs into
a miniature connector extending out the back of the
extensometer connector. When plugged in, it shunts across
one arm of the sensor and shifts the output to a precise
value recorded on the extensometers calibration certificate.
Calibration
requires only these two simple steps:
1. Mount the extensometer on a sample. Adjust the output
to read zero. This sets point 1 in the example graph.
This is the zero offset or tare.
2. Plug in the Shunt Module. Adjust the output readings
to precisely the value provided. This sets point 2 in
the example. This amounts to adjusting the gain or amplification.
That’s all it takes. This process works for almost every
situation Epsilon has encountered. Further information
is provided with every module. This works even if the
test controls have internal shunt calibration capability.
It is useful for digital systems which read in strain
directly, as well as older system which read in volts.
It may be used for data acquisition systems and stand
alone signal conditioning electronics. For controls
which only allow for one extensometer, it’s a quick
way to switch over to a second.
For systems with multiple calibration ranges, as common
in materials testing, multiple Shunt Modules may be
ordered, each set for the range specified.
Shunt
Calibration Modules allow periodic re-calibration
of your extensometer by sending it back to Epsilon.
They also provide a quick means to check that your
electronics is properly set and has not shifted.
CALIBRATION
SERVICES, INC.
300 Buttertown Road
Emlenton, PA 16373
(724) 867-6664 or (800) 793-1870
FAX (724) 867-1346
