Global Sources
EE Times-Asia
Stay in touch with EE Times Asia
EE Times-Asia > Sensors/MEMS

Fluid sensors have automatic calibration function

Posted: 22 Jun 2011 ?? ?Print Version ?Bookmark and Share

Keywords:optoelectronic? fluid sensors? self-calibration system?

The optoelectronics business unit of TT electronics plc has developed a self-calibration system for its OPB350 series optoelectronic fluid sensors. The system is designed to save engineers set-up time, as well as maintain the sensors' optimum accuracy over years of operation.

Designated as the OCB350 series, the non-contact fluid sensor features an automatic calibration function that can be used to compensate for manufacturing, environmental and system variances inherent with optical devices. This self-calibration feature is designed for medical equipment used to deliver IV fluids, transfusion/infusion systems, blood plasma and urine analysis; as well as precision industrial applications where tubing is used to deliver toner, lubricating oil, or other clear or colored fluids.

The sensor operates with an infrared LED/phototransistor pair to determine the presence or absence of fluids in a tube that passes through the sensor housing, using the difference in refractive properties to vary the output current to signal different states, including 'fluid present,' 'no fluid present,' and 'no tube present.' It can also be used to identify the presence of air bubbles in the fluid passing through the tube.

According to the company, the auto-calibration function enables the design engineer to narrow the device's initial output state, which helps maintain consistent switching performance by compensating for several factors, including ambient light variation; LED/phototransistor performance degradation over time, overall system power variations; and fluctuations in ambient temperature. The calibration settings are maintained, even if power is lost to the device, which enables faster startup mode without the need for calibration each time the sensor is initiated. In addition, the sensor can be calibrated remotely before installation.

The OCB350 series devices include the sensor mounted on a PC board with an interface cable, and a series of colored LEDs to indicate the various states of calibration. Custom PC boards can also be developed to meet customer requirements.

The OCB350 series auto-calibrating fluid sensors are available to fit applications using clear tubing with outer diameters of 1.6mm, 3.2mm, 4.8mm or 6.3mm. Wide operating temperature range is from -40C85C.

Article Comments - Fluid sensors have automatic calibra...
*? You can enter [0] more charecters.
*Verify code:


Visit Asia Webinars to learn about the latest in technology and get practical design tips.

Back to Top