Product Description Hdd/20 - Bosch Rexroth BODAS DSA/12 Instruction Manual

22/36 BODAS speed sensors | About this product
Application examples
Example
Four basic variants
available
Bosch Rexroth AG, RE 95290-01-B/2021-09-13

5.4 Product description HDD/20

The hall-effect speed sensor HDD/20 is used for contact-free measurement of
rotational speeds. Two hall-effect semiconductor elements inside the sensor
measure changes in the magnetic flux caused by a ferromagnetic spline on the
sensor. These are converted into square-wave signals by the integrated electronics.
Due to its sturdy design the sensor is suitable e.g. for integrated use with
axial piston units from Rexroth.
A6VM axial piston variable motor with mounted speed sensor HDD/20
Variable motor A6VM
Fig. 13: A6VM with mounted speed sensor HDD/20
• HDD1 series 20 returns a square-wave signal which is proportional to the speed
as well as a switching signal for detecting the direction of rotation.
• HDD2 series 20 returns two square-wave signals that are phase shifted by
approx. 90° which are suitable for the redundant detection of the rotational speed.
In addition, this can be used, for example, to calculate the direction of rotation
using a Rexroth control unit.
Both variants are available with NPN (standard) or PNP output circuitry.
Hall-effect speed sensor (HDD)