Sensor Calibration Boards Optek / TT Electronics Sensor Calibration Boards eliminate the guesswork from calibrating Optek devices. The OCB350 sensor calibration board helps with calibration of OPB350 series fluid sensors. The Optek OCB100 sensor calibration board is for calibration of reflective sensors and slotted switches. Both boards feature four LEDS on board that indicate when the device is calibrated, not calibrated, has reached the logical trip higher than the calibration point, or has reached the logical trip lower than the calibration point. The boards also provide an analog output for critical measurements.