User Manual

8/12 Bosch Rexroth AG
DSM Series 10
RE 95132/11.08
Application on controllers
Application with Rexroth BODAS controllers
The reading of the DSM1-10 is possible with the following
BODAS controllers: series 21, 22 and 30.
RC2-2/21
2 inputs
22
7
18
DSM
17
DSM
RCE12-4/22
2 inputs
51
DSM
20
51
DSM
9
8 V
(intern)
8 V
(intern)
RC4-6/22 (2 inputs), RC8-8/22 (4 inputs),
RC12-8/22 (4 inputs)
comparable to RCE12-4/22
RC36-20/30
6 inputs
112, 113, 110, 111, 109, 108
DSM
146
Note
The current data sheet of the controller being used is to be
considered.
Application with different controllers
Basic use
Frequency input
Controller
–
–
+
+
I
DSM
R
Current I supplies the sensor information in the form of pulses
(details see Page 5) whose low and high levels are as follows:
I minimum nominal
maxi-
mum
unit
I low 5.9 7 8.4 mA
I high 11.8 14 16.8 mA
The minimum pulse width is 37 µs. This corresponds to a
frequency of 27 kHz.
In order to interpret the signal, it must be ensured that at
30 kHz input frequency the signal (after any low-pass filter that
may be present) still exhibits a sufficient voltage difference (∆V)
for the evaluation .
V
low-pass
filter
Through resistance R, a voltage is generated that is applied to
the frequency input of the RC controllers.
In an example with R = 200 Ω, the following voltages are read:
U input
(R = 200 Ω)
minimum nominal
maxi-
mum
unit
U low 1.18 1.4 1.68 V
U high 2.36 2.8 3.36 V
The resistance R to be installed should be selected so that:
The voltage difference for the internal signal evaluation in the –
controller is sufficient.
The maximum voltage across resistance R does not become –
too high (adapted to the sensor supply), in order for at least
4.5 V always to be applied at the sensor pins.
If these conditions are met and the signal is present inside the
controller, the sensor information can be determined.
Speed
Due to the properties of the DSM, which sees both flanks of
each gear tooth, the actual speed frequency of the gear is
determined as follows
f
gear
= f
read
/ 2
Direction of rotation, critical air gap, standstill
To determine this information, the length of the pulse should be
measured. This can be accomplished by the start time and end
time of the pulse being measured in the controller.
Nevertheless, the speed can always be read from this frequency
without this evaluation. However, the performance during
standstill should be considered (1.44 ms every 0.7 s). It can be
detected in the excess length of the pulse (1.44 ms).