Magnetic Sensing Head Technology
A sensing head is a device to measure the magnetic information from a magnetic scale and convert it to a signal that can be used in the connected electronics. There are different types of sensing heads based on the sensor used, the output delivered (digital or analogue signal) and the level of signal processing in the sensing head.
The key element of a sensing head is the sensor. The different types of sensor technology - Hall sensors or magneto resistive sensors - are used to read the magnetic pattern and convert them to a electric signal that is used for a motion controller or other electronic controller to assess the information.
The different types of sensor technology can be used for distinctive tasks. Hall sensors are available as switching or linear sensors. Switching hall sensors can be best used for detecting positions on a scale, while linear hall cells provide an output, that is different over different parts of a scale. Magneto resistive element provide an information that is similar to linear Hall sensors.
The signal from the sensor is not optimal. Signal conditioning is used to optimize the output from the sensor and to provide the best possible information.
Signal processing and converting
The signal processing enriches the signal and converts the analog signal to a digital signal. Using analogue/digital converters, the signal is processed and can be provided in many different outputs.
BOGEN offers incremental sensing heads with RS485 ABZ or HTL outputs.
A standard output is to convert the analogue signal to a format, where the signal is converted to two square wave with a 90 degree shift, which are delivered on the A and B channel of the interface. The reference information is delivered as Z channel. BOGEN offers ABZ on most of the incremental encoders.
The BOGEN sensing heads also offer TTL/HTL output.
BOGEN offers absolute sensing heads with SSI or BISS-C outputs.
The serial signal interface enables the serial delivery of information. The sensor provide serialized absolute position information in the defined binary format.
The open source standard was defined by IC Haus and provides serial interface with a device identification.