RC Sensor Calibrations
Philtec recently performed calibration tests on their sensors, using different target materials supplied by their customers. Calibrations were made to 4 different metal targets without adjusting the gain output control. Only the SNR control was varied to 3-4 volts max to optimize the signal for each target.
The four targets were:
- Dull Metal: A dull metal target was the first material tested. The sensor output was set to 5.0 volts at 12.5 mm (max range).
- Round Machined Metal: A round machined target was next. It had a very similar output sensitivity, about 5% lower than target #1.
- Polished Metal: A highly polished metal target was third. Its output sensitivity was about 17% higher than target #1.
- Diffuse Aluminum: An anodized diffuse metal target was fourth. It had an output sensitivity 20% lower than target #1.
Graphical results for these calibration tests appear in Philtec Application Note #72, entitled “RC Sensor Calibrations.”
Machined surfaces can span the range from diffuse to specular reflectors. Rough machined surfaces are diffuse reflectors. Ground finishes can fall in between totally diffuse and totally specular. The charts in the Application Note illustrate this point. A 2 micro-inch ground finish reflects essentially as a mirrored surface. A 63 micro-inch ground surface is essentially a diffuse reflector. For best results, it is always good practice to calibrate a sensor to the same machined surface to be measured.
Philtec Inc. is a manufacturer of custom fiber optic displacement sensor systems. Based in Annapolis, Maryland, Philtec has been providing innovative sensing solutions since 1988. These sensors are designed to operate in harsh environments, such as high temperature, cryogenic, high pressure, vacuum, and high magnetic field. Philtec sensors are built in the USA and sold worldwide. Their engineers can help you design special sensors uniquely meeting your requirements. Applications for Philtec’s sensors include:
- Engines
- Turbines
- Flight
- Computer printers and hard drives
- Oil Well Drilling
- Measurement
- Medical equipment
- Motion control
To request more information or a quotation for Philtec products, contact IL Photonics.