information sheet speed sensors on mcr motors

RE 15225-06/01.2017, Bosch Rexroth AG

Sensors used in current MCR motorsThere are at present five sensors that can be outfitted: P1, P2, DSM, DSA1, DSA2

The “P-number” of the MCR motor code indicates the sensor selection:

▶ P – Single channel 24V (obsolete) ▶ P0 – Speed sensor ready (for P1, P2) ▶ P1 – Speed Sensor P1, dual channel 10V ▶ P2 – Speed Sensor P2, dual channel 24V regulated ▶ P3 – Speed sensor ready (for DSA & DSM) ▶ P4 – Speed sensor DSM – 12V ▶ P5 – Speed sensor DSA2 – 12 + 24V ▶ P6 – Speed sensor DSA1 – 12 + 24V ▶ P9 – Single channel 10V (obsolete)

IntroductionIn all standard MCR motors, there is the option to have a contactless speed sensor installed in the motor. The sen-sors operate with the Hall-effect, which detects a change in magnetic field flux across an air-gap when a ferromagnetic gear tooth passes the sensor surface. Sensors can then be connected to a controller, such as the Rexroth BODAS controller, in order to give information to the vehicle driver about the motor’s speed and direction of the rotation.

Information sheetSpeed sensors on MCR motors

RE 15225-06Edition: 01.2017

ContentsSpeed sensor selection guide 2Sensor comparison 2P1, P2 Output 3DSA1, DSA2 Output 4DSM Output 5References 6

Bosch Rexroth AG, RE 15225-06/01.2017

2 Speed sensors on MCR motorsSpeed sensor selection guide

Speed sensor selection guide

Operating supply voltage

(DC)

Nominal supply voltage

(DC)

Transient protection

Standstill recog nition

Rated pressure

O-ring type Output connection

Detection of frequency

and direction

Output waveforms

Output magnitude

n = Motor RPMf =output freq.

z = # teeth

P1 4.5-10V (regulated

supply)

10V (regulated

supply)

Short-circuit protection for all pins

Yes 10 bar 12.42 × 1.78mm,

Viton, 90 Shore

4 pins, DEUTSCH DT04-4P

connector

Yes 2x phase displaced

square waves

Output voltage = supply voltage (open-circuit)

n = f × 60z

f = n × z60

P2 10.5-28V 12V and 24V

Yes Yes 10 bar 12.42 × 1.78mm,

Viton, 90 Shore


connector


square waves

5V DC regulated

output

n = f × 60z

f = n × z60

DSM 4.5V-20V 12V RC element, diode or

varistor must be used

parallel to load

Yes 5 bar – 2 pins, AMP, material number

1-967644-1

Yes 1x square wave, pulse lengths indicate direc-

tion of rotation, frequency, air gap warnings

Current modulated out-put, controller

circuitry must be compatible

n = f × 60z × 2

f = 2n × z60

DSA1 8-32V 12V and 24V

Thermal short-circuit

limitation

Yes 10 bar 8.5 × 1mm, HNBR 70 Shore A


connector

Yes 1x frequency square wave, 1× direction

signal

dependant on sensor resis-

tance, external resistances,

supply voltage

n = f × 60z

f = n × z60

DSA2 8-32V 12V and 24V

Thermal short-circuit

limitation

Yes 10 bar 8.5 × 1mm, HNBR 70 Shore A


connector


square waves

dependant on sensor resis-

tance, external resistances,

supply voltage

n = f × 60z

f = n × z60

Sensor comparison

The only difference between sensors P1 and P2 is their required power supplies. P1 requires a regulated, low voltage DC supply (10V), while P2 requires a higher voltage supply (12V or 24V) that can be unregulated. The output waveforms of P1, P2, and DSA2 are dual phase displaced square waves, while DSA1 and DSM have unique wave-forms. DSM is the only sensor with a 2-pin connector and is the least rugged of the sensors, but allows for the most information to be transmitted.


Speed sensors on MCR motors P1, P2 Output

3

P1, P2 Output

The P1 and P2 sensor output consists of two square waves, on channels 1 and 2. The square wave pulses represent the passing gear teeth, and the phase displacement between the two signals allows for determining the direction of the motor’s rotation. During clockwise rotation, square wave pulses on channel 1 lag behind the pulses on channel 2 by approximately 140 degrees. During counter-clockwise rotation, the square wave pulses on channel 1 lead ahead of the pulses on channel 2 by approximately 140 degrees. As the speed of the motor increases, the pulse period will shorten; the motor RPM is equal to the frequency of the pulses divided by the number of teeth on the gear, times sixty.

For the P1 sensor, the voltage amplitude of the square wave pulses is equal to the supply voltage when open-circuit, but once connected will depend on the resistance of the elec-tronics connected to the output. The P2 sensor contains regulator circuitry and has an output of 5V DC. Refer to the datasheet DO/100/117 for more information.

▼ Clockwise rotation

Channel 1

Channel 2

Approx. 140°

▼ Counter-clockwise rotation

Channel 1

Channel 2

Approx. 140°


4 Speed sensors on MCR motorsDSA1, DSA2 Output

DSA1, DSA2 Output

Like the P1 and P2 sensors, the DSA1 and DSA2 sensors also express motor speed via square wave output. The motor RPM is equal to the frequency of the pulses divided by the number of teeth on the gear, times sixty.For more information refer to page 2 of the DSA data sheet 95133.

DSA1 OutputThe DSA1 sensor has only one square wave output S1 that indicates the frequency of passing gear teeth. The other output D is a digital output that indicates the direction of rotation: a high output indicates clockwise rotation and a low output indicates counter-clockwise rotation. The output voltage of the DSA sensors depends on the sensor resistance, the external load resistances, and the supply voltage. For more information see page 5 of the DSA datasheet 95133.

Signal output DSA1 ▶ One square-wave signal (S1) and one digital direction of

rotation signal (D) on a gear wheel.


DS1

2 V

UOut

Time t360° phase


D

S1

2 V

UOut

Time t360° phase

DSA2 Output The DSA2 sensor’s output is similar to the output of the P1 and P2 sensors, but the leading/lagging convention is reversed. For clockwise rotation, the pulses of signal 1 will lead the pulses on channel 2 by a minimum of 15 degrees. During counter-clockwise rotation, the pulses of signal 1 will lag the pulses on channel 2 by a minimum of 15 degrees.

Signal output DSA2 ▶ Two phase-shifted square-wave signals with minimum

defined phase shift of 15 degrees between output 1 (S1) and output 2 (S2).


S2S1

2 V

UOut

min. 15° Time t360° phase


S2S1

2 V

UOut

min. 15° Time t

360° phase


Speed sensors on MCR motors DSM Output

5

DSM Output

The signal output of the DSM is different to the other sen-sors, and more complex. For more in-depth explanations refer to page 4 of the DSM datasheet 95132.

Unlike the other sensors, the DSM output pulse lengths do not change with changing motor speed. Instead, evaluation electronics on the DSM produce square wave pulses whose lengths provide information about the motor’s direction of rotation (DR): the signal “DR clockwise” is a pulse of length 180μs, and is twice as long as the signal “counter-clockwise.”

Every rise and fall of the internal gear signal triggers a pre-bit low, followed by the signal pulse. As the motor speed increases, the time between pulses will shorten. The pre-bit low exists in order to prevent the signal pulses from “merging” into each other at very high frequencies and becoming indistinguishable from one another. If the fre-quency is so high that the full length of the signal pulse cannot be completed, the sensor simply outputs the fre-quency and assumes that the direction of rotation has not changed, since a slow-down would first be necessary.

▼ Signal form

Xn Xn+2

Sensor internal rotary signal (corresponds to gear)

DR L width = 90 ms typical

DR R width = 180 ms typical

Transmitted signal: DR counter-clockwise

Transmitted signal: DR clockwise

Prebit low = 45 ms typical

Since the DSM is triggered by both sides of the gear tooth, the frequency read by the sensor is two times the actual frequency of the gear. The speed is then determined in the same way as the other sensors. (See the table for formulas)

During standstill, where the motor is not rotating, the DSM sensor will output pulses 1.44ms in length (32xLR) every 0.7 seconds. For further information refer to page 6 of the DSM datasheet 95132.

DSM – controller connectionThe DSM sensor can easily be connected to Rexroth BODAS controllers. However, since the DSM’s output is current modulated instead of voltage modulated, if a different controller is to be used care must be taken to select appro-priate resistor values. See page 7 of the DSM datasheet 95132 for more information.

6


Speed sensors on MCR motorsReferences

Bosch Rexroth LimitedViewfield Industrial EstateGlenrothes, FifeScotland, KY6 2RDUKPhone +44 15 92 631 777Telefax +44 15 92 631 [email protected]

© Bosch Rexroth AG 2017. All rights reserved, also regarding any disposal, exploitation, reproduction, editing, distribution, as well as in the event of applications for industrial property rights. The data specified within only serves to describe the product. No statements concerning a certain condition or suitability for a certain application can be derived from our information. The information given does not release the user from the obligation of own judg-ment and verification. It must be remembered that our products are subject to a natural process of wear and aging.

References

▶ Speed Sensor – DSM series 10, datasheet RE 95132 ▶ Speed Sensor – DSA series 12, datasheet RE 95133 ▶ Speed Sensors – P1 and P2, datasheet DO/100/117 ▶ Hall-Effect – “Hall-Effect Sensors, Theory and

Application” Edward Ramsden, 2006

information sheet speed sensors on mcr motors

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