Bosch rexroth MBT, Manual

Page: 401 / 422

13.6 Determining the polarity of the encoder system
In order to avoid direct feedback in the velocity control loop, the effective di‐
rection of the motor torque and the count direction of the encoder system
must identical.
Different effective directions of motor torque
and count direction of the encoder system
cause uncontrolled movements of the motor
upon switch-on!
WARNING
⇒ Secure against uncontrolled movement
⇒ Setting the effective direction of the motor torque to the counter direction of
the encoder system
Position, velocity and force data may not be inverted when the encoder sys‐
tem count direction is set. Ensure that the following parameters are set be‐
fore the encoder polarity is checked:
Parameter Description Value
S-0-0085 Torque/force polarity parameter 0000000000000000
S-0-0043 Velocity polarity parameter 0000000000000000
S-0-0055 Position polarity 0000000000000000
Tab. 13-3: Table of polarity parameters
The encoder polarity is set by means of parameter S-0-0277, Position feed‐
back 1 type (bit 3); see fig. 13-2 "Direction of rotation of the rotor, as viewed
from the cable output side at the stator (MST)" on page 390 and tab. 13-4
"Parameter S-0-0277" on page 390 .
Direction of rotation of the motor The direction of rotation of the motor or the rotor of MBT motors can be deter‐
mined by means of the cable output side at the stator.
The following example starts from the assumption that the encoder manufac‐
turer has provided a positive count direction with a view to the encoder shaft
and the encoder shaft rotating in clockwise direction.
For the actual definition of the count direction of your encoder, please refer to
the encoder manufacturer's encoder data sheet.
MBT High Synchronous Torque Motors 389/409
Commissioning, operation and maintenance
R911298798_Edition 08 Bosch Rexroth AG