What equipment is a rotary sensor used for?
What is the detecting distance?
Can the sensor be used in a very dirty environment?
What precautions should be followed when mounting this rotary sensor?
What gear material is best suited to detection with the sensor?
What is the magnitude of detectable modules?
What is the distortion rate of the output waveform?
Can standstill (0Hz) be detected?
What is the response frequency?
Are current output or 2-wire output possible?
To what extent can the rotary sensor be made more compact?
Can the rotary sensor be used in a vacuum or corrosive atmosphere?
See "Summary" and "Selection Guide of Rotary Sensors". Rotary sensors are suited to rotation, linear motion and proximity sensing at high speed. Products with custom specifications are available. Contact us for details.
When the target is a gear, the detecting distance varies depending on the gear module and sensor sensitivity. For 8-bit detection, the detecting distance is 0.2mm when the module is 0.4, and 1.5mm when the module is 2.
Output voltage is attenuated in inverse proportion to the square of the distance between the sensor and target. Refer to "Output Voltage/Gap Characteristic".
This rotary sensor is resistant to very dirty environments except those containing magnetic substances such as iron powders. Therefore, this sensor is used for applications different from encoders incorporating an optical sensor.
Set the sensor on the centerline of the gear. The sensor is directional. Referring to the Terminal Connection Diagram, set the sensor so that the sensor's direction of detection is parallel to the gear's direction of rotation. Use a thickness gauge or the like to mount it the specified distance from the gear. Although the sensor's detecting surface is protected with a metallic enclosure, the sensor may be damaged if it is subject to an impact hard enough to cause visible damage to the enclosure. Contact us if special adjustments are required. See "Combination of Pulser and Sensor". For the sensor tightening force, contact us.
Although the best material is a ferrous metal attracted by a magnet, especially pure iron, ordinary low carbon steel (S45C, SS21) is recommended. As the target, a gear is ideal for obtaining the best performance from the sensor, but a magnetic drum whose magnetization is applied in segments to the circumference of a drum made of a material with a high holding capacity can be detected effectively. Magnetic gears are suitable for pulsers of Murata's sensors.
The "module" is related to the tooth-to-tooth pitch of gears. The module is the value obtained by dividing the pitch diameter of a gear by the number of the teeth; the value obtained by multiplying the module by pi (3.14) is the tooth-to-tooth pitch. The sensor's element-to-element pitch should be one-half of the tooth-to-tooth pitch.
The larger the module, the larger the sensor to be used. Considering value, the maximum module is approximately 3. However, we offer products applicable to a variety of modules. Contact us for details.
The distortion rate varies with the setting conditions. See "Waveform Distortion Rate".
Because this rotary sensor is a resistance change type, it can detect a standstill position.
A passive-type coil sensor, however, provides output characteristics proportional to the speed; therefore, it is difficult to detect standstill with this type of sensor.
Although the response frequency varies slightly depending on the pulser's material, it is generally 0 to 100kHz. The cut-off frequency is at the megahertz (MHz) level.
Both are possible.
Detection is performed by inserting a pull-up resistor and using 2-wire power supply and current signal lines.
2-wire output block diagram
The sensor size is determined by the area of the built-in elements. This area is determined by the operating temperature range, the module and the number of output phases when the pulser is a gear. When the number of phases is two, the operating temperature is 80°C, and the module is 0.4, the enclosure measures approximately 17mm in outside diameter and 18mm in height.
Products with custom specifications are in use in such environments. Contact us for details.
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