Dynisco “R-CAL” Feature Explained

David Azevedo, Global Technical Support Manager

09.02.2020

For over 60 years, Dynisco pressure sensors have been used in various applications around the world. The original patent holder for the melt pressure sensor used in extrusion, Dynisco has remained the world class industry leader in this technology by working side by side with our end users to meet the ever changing demands of the plastics market.

In this blog, we will explore the unique feature known as “R-Cal” which is a standard for the majority of the Dynisco pressure sensor product offering.

R-Cal stands for “resistance calibration”, and it is used to force a known signal output from the pressure sensor, which is at rest with no pressure present.

The signal is scaled to exactly 80% of the full scale value, which can be measured in millivolts, milliamps, or volts.

Without a pressure source, verification of the instrumentation scaling is difficult, thus this feature provides a means to test that the sensor and instrumentation have been scaled properly together.

For example:

A Dynisco model PT462E-10M-6/18 has a signal output range of 0-33.3mV (3.33mV/V). The pressure range is 0-10,000 psi, +/- .5% of the full scale range.

When “R-CAL” is engaged via the two dedicated pins CAL 1 and CAL 2, there will be exactly 80% signal output which is the equivalent of 26.64mV.

If the instrumentation has been scaled correctly, the user would expect to see 8000 psi on the display, while the R-CAL has been shunted via connection of the dedicated pins.

Several instruments, such as the Dynisco UPR900 (UPR800/UPR700/UPR690) have a built in sequence for performing this calibration check.

The following slide illustrates what this feature looks like:

It is important to note, that this procedure is used to verify instrumentation is accepting the signal range appropriately, and is not intended as a means for confirming the mechanical response to pressure of the sensor itself.

In order to verify the pressure sensor is reading pressure correctly , the user would need a calibrated, pressure source, such as a dead weight tester or a hydraulic pump. For this purpose, Dynisco offers our model PPS1100 (Portable Pressure Source) which can accommodate pressure ranges up to 10,000 psi.

R-Cal is a feature that has helped numerous users verify their instrumentation, without having to remove equipment from the process.

This feature is one of many, that separate Dynisco pressure sensors from our competitors.

Please contact Dynisco’s team of experts, to learn more about features that may be available for the models you are currently using, so that we may assist in your continuous improvement efforts.