Bosch Rexorth Speed sensor DSM 1/20 TYCO-AMP SU& R917011890 Rexroth

Bosch Rexorth Speed sensor DSM 1/20 TYCO-AMP SU& R917011890 RexrothThe Hall effect-based DSM1-10 speed sensor has been specially developed for use under harsh conditions in mobile working machines. The sensor collects the speed signal of ferromagnetic gear wheels or punching sheets. As an active sensor, when it does this it delivers a signal with a constant amplitude that is independent of the speed. The sensor distinguishes itself not only due to the fact that it can detect the direction of rotation, but also because of its additional diagnosis functions such as:Standstill detectionCritical air gapCritical installation positionExample applicationsDue to its compact and robust design, the sensor is suitable for integrated useIn the wheel bearing for wheel speed acquisitionIn the transmissions or gear stagesFan drives in buses, trucks and construction machinery (7 to 20 kW)In vibration drives for road rollers and pavers Example:Axial piston motor with DSM external gear motorElectrical circuit USensor​ Sensor operating voltage Usup Supply voltage URM Signal voltage at measuring resistor Ilow, Ihigh Sensor current RM Measuring resistorA two-wire current interface is used for signal transmission. The sensor supplies a current signal. The low current (Ilow = own current of the active element) is interpreted as a low signal. The high current (IHigh =Ilow + ∆I; ∆I = additional current from a path parallel to the active element) is interpreted as high current. The current received in the control unit from the sensor at a measuring resistor RM is converted to a voltage signal. The evaluation circuit detects whether a high signal or low signal is present on the basis of the voltage level.Electrical circuit diagram when the sensor is supplied by the on-board power supply batteryIf the sensor is supplied by the control unit, the operating voltage specified in this data sheet must be observed. Output signalsThe DSM1-10 output signal is made up of square-wave signals of constant amplitude which are produced by the DSM1-10 evaluation electronics. The length of the individual pulses provides information about the direction of rotation and any errors in the installation position.The evaluation electronics generates a high pulse of a defined length after each edge of the sensor-internal speed signal, whereby the length of the high pulse is defined by the information to be transported. This, for example, the information direction of rotation left is described by a 90 µs long pulse and the information direction of rotation right by a 180 µs long pulse.In order for the rotational speed information to still be output when there are long, high pulses at higher speeds, a low-time (pre-bit low) is always inserted ahead of the high pulse. So although the additional information within the signal is lost at higher rotational speeds (pulses are truncated by the low-time feature), reliable output of the rotational speed information is pos