Establishing Position Data Reference For Relative Measuring Systems - Bosch Rexroth IndraDrive MPH-02 Functional Description

MPH-02, MPB-02, MPD-02
Checking the Absolute
Evaluation of Encoders
Checking Whether Position Data
Reference was Established
Actual Position Value Offset
Mapping the Position Reference
Bits to the Drive Status Word

Establishing Position Data Reference for Relative Measuring Systems

Actual Position Value of Relative
Measuring Systems when
Switching On
Establishing the Position Data
Reference
DOK-INDRV*-MP*-02VRS**-FK01-EN-P
Notes on Commissioning
The possibility of absolute evaluation of motor encoder or external
encoder is displayed by the respective bits of the following parameters:
• S-0-0277, Position feedback 1 type (motor encoder)
• S-0-0115, Position feedback 2 type (external encoder)
The position status of motor encoder and external encoder is displayed in:
• S-0-0403, Position feedback value status
If required by the master, the position status of one of the two encoders
can be mapped to bit 0 of S-0-0403. This is done by setting the bit for
encoder selection in S-0-0147, Homing parameter.
Note: If
• on the master side the validity of the actual position values
is checked via bit 0 of S-0-0403 and
• motor encoder and external encoder have been homed,
the encoder selection in S-0-0147, in the position-controlled
modes, should also be changed accordingly when changing
the position encoder.
The change in the actual position value by establishing the position data
reference is displayed in the following parameters:
• S-0-0175, Offset parameter 1 (motor encoder)
• S-0-0176, Offset parameter 2 (external encoder)
The respective bits of parameter S-0-0403, Position feedback value
status can be assigned to the real-time status bits of S-0-0135, Drive
status word, if required.
Brief Description
See also "General Information on Establishing the Position Data
Reference"
After the drive is switched on the actual position values signaled by
relative measuring systems do not yet have any reference to the machine
axis. Measuring systems can be installed at the motor (motor encoder)
and directly at the mechanical axis system (external or optional encoder).
For encoder arrangement and mechanical axis system see also
"Measuring Systems for Motor and Axis Control, Arrangement" in chapter
"Mechanical Axis System and Measuring Systems"
The position data reference of relative measuring systems to the axis has
to be established again each time after the drive was switched on or after
all procedures that cause the position data reference to get lost.
After master-side start of the respective command the drive automatically
establishes the position data reference.
In the case of relative measuring systems, it moves the axis until the
controller can detect a dedicated point. The actual position values then
are automatically switched to axis reference. The presettings for the
8-7
Drive Functions