GLM700 family GMR tooth sensor modules for angle and length measurement
General information
The sensors in the GLM700 family are FixPitch sensors based on the Giant MagnetoResistive (GMR) effect. A magnet is located in the sensor housing so that the sensors can be used on tooth structures.
The sensors offer
- Differential sine and cosine output signals
- Extremely low harmonic signal quality
- Package suitable for SMD assembly (waffle pack delivery form)
- Possibility of use on passive measurement scales (tooth structures)
Product variants
This product family has five sensor variants for you to choose from.
- GLM711 FixPitch sensor for a tooth structure with a pitch of 1 mm
- GLM712 FixPitch sensor for a tooth structure with a pitch of 2 mm
- GLM713 FixPitch sensor for a tooth structure with a pitch of 3 mm
- GLM714 FixPitch sensor for a tooth structure with a pitch of 0.94 mm (m 0.3)
- GLM715 FixPitch sensor for a tooth structure with a pitch of 1 mm (m 0.5)
Design features
The sensor is a FixPitch sensor, adjusted to a certain tooth pitch. The sensor has an integrated magnet in order to activate the ferromagnetic tooth structure magnetically.
The sensor design is based on PerfectWave technology which improves the signal quality by suppressing the harmonics.
Application examples
Suitable for absolute or incremental applications (linear or rotary motion) e.g.:
- Motor commutation
- Speed measurement
- Linear motors
General information
The sensors in the GLM family are FixPitch sensors based on the Giant MagnetoResistive (GMR) effect. The sensors were developed specifically for use in ferromagnetic tooth structures. A magnet is therefore integrated into every sensor to stimulate the tooth structure.
This operating principle allows existing machine elements, such as gear wheels or threaded spindles, to be used as measurement scales. These must have a ferromagnetic material property and must have a tooth pitch that matches the sensor pitch.
No specific tooth forms are required. Sensors can therefore also be operated on a hole structure or a square tooth structure.
Product variants
| Name | Pitch | Amplitude | Offset | Bridge resistor |
|---|---|---|---|---|
| GLM711 | 1 mm | 9 mV/V | ±3 mV/V | 5.5 kΩ |
| GLM712 | 2 mm | 9 mV/V | ±3.5 mV/V | 5.7 kΩ |
| GLM713 | 3 mm | 9 mV/V | ±3.5 mV/V | 5.7 kΩ |
| GLM714 | 0.94 mm (m 0.3) | 9 mV/V | ±3 mV/V | 5.6 kΩ |
| GLM715 | 1 mm (m 0.5) | 9 mV/V | ±3 mV/V | 5.8 kΩ |
GLM700
By adjusting the sensors to a defined tooth pitch, the sensors achieve a very high signal quality and provide differential sine and cosine signals.
All sensors from the GLM700 family feature PerfectWave technology and provide extremely low harmonic output signals. They are available as components suitable for SMD assembly in the waffle pack.
The connecting pins are arranged on one side of the sensor, which enables an off-axis arrangement for applications at the shaft circumference.
Data sheets
- GLM700
Collective data sheet for FixPitch sensors in the GLM family
Product information
- GLM700 brochure
Product information on the GMR tooth sensor modules
Application information
- GLM700 processing
Application advice for processing the GLM sensors
- GLM700 tooth structures
Application note for possible tooth structures for GLM sensors
- GLM700 amplitude information
Application note on adjusting the amplitude of the GLM sensors <available shortly>
CAD drawing
- GLM700 family
3D PDF
Your contact person
Design features
Sensitec is increasing the sensor efficiency by means of various design modifications to the chip layout. The patented solutions, described more closely below, also contribute to better signal quality, reduced sensitivity to stray fields and increased control accuracy.
FixPitch
FixPitch sensors are adjusted to the pole lengths of the measurement scale, i.e. MR strips are geometrically coordinated to a specific pole length. The sine and cosine signals are generated by distributing the Wheatstone bridge resistors along the single pole. This geometric arrangement contributes to the suppression of the harmonics and a reduction in the sensitivity to stray fields. This optimizes the linearity of the sensor.
PerfectWave
The PerfectWave design is applied in order to optimize the signal quality of the FreePitch sensors. The MR strips that serve as resistors have a curved form which is used to filter the harmonics when mapping the magnetic field direction in an electric signal. This filtering is implemented using the special geometry and arrangement of the MR strips and does not cause any additional signal propagation delay. The PerfectWave design is particularly effective for small magnetic fields and results in improved linearity, higher accuracy and better signal quality.