Lynx™ Embedded Sensors LES‑B‑127‑50/125/500/2000 | Product Manual
48
CALIBRATION
RJG recommends that sensors be
calibrated every year, but the need for
regular calibration depends largely on
the accuracy required for the application
and the requirements of individual quality
systems and industry regulations.
RJG sensors are designed to hold
calibration for operating life. The vast
majority stay within a 2% accuracy
specification, which is sufficient for most
customer applications.
COMMON FACTORS AFFECTING SENSOR
RECALIBRATION
1.
Required Application Accuracy
Some applications require more accuracy
than others. If using cavity pressure control
on a precise part with a narrow processing
window, it may be important to maintain
sensor calibration to within 1%.
If simply detecting short shots, calibration
shifts of 5% or more may be tolerated. As
a point of reference, a 2% calibration error
means that a cavity pressure of 3,000 psi
(207 bar) may read as low as 2,940 psi
(203 bar), or as high as 3,060 psi (211 bar),
which is insignificant in most applications.
For most applications, calibration accuracy
of 2% is more than sufficient, and is used
by RJG as the specification for repaired
sensors.
TESTING & CALIBRATION (
continued
)
2.
Quality System Regulations
If US Food and Drug Administration (FDA)
quality system requirements must be met,
or those of other stringent quality systems,
sensor calibration may be required.
However, even in these cases, there is
often flexibility to adjust guidelines to meet
the needs of the application.
3.
Sensor Cycle Count
In the most aggressive environments, it
takes at least 100,000 cycles for a sensor
to show significant calibration errors. In
more typical applications, calibration will
remain stable for 500,000–1,000,000
cycles. Even then, many sensors in the
field with multiple millions of cycles show
little calibration shift. If a sensor is in a low
volume mold that sees fewer cycles, the
need for sensor recalibration is minimized.
4.
Sensor Load
The higher the peak load on the sensor,
the more the loading nub can wear—and
the higher the potential for calibration shift.
Low force sensors (125‑pound sensors, for
example) show less calibration shift than
high force sensors (2000‑pound sensors);
sensors that run at the lower end of their
force range (less than 40% of full scale)
show less calibration shift than sensors that
run at the high end of their range.
