Festo CMMP-AS-***-M3 Series, Description

Page: 36 / 132

6 Functions
36 Festo – GDCP-CMMP-M3-FW-EN – 1203NH
6.2.3 Homing parameters
The following parameters must be set for homing:
Parameter Description
Speed The parameter setting applies for:
– Searching travel to the primary destination
– Crawl travel for identification of the switching point in the homing method
“Limit switch” or “reference switch”
– Travel to the axis zero point.
Acceleration/
deceleration
Smoothing
Axis zero point Definition of the axis zero point
Default values as a function of the set search direction
Linear axes ±3.00 mm (±0.100 in)
Axis of rotation ±10° (±0.030 R)
Tab. 6.9 Homing parameters
– Select the speed so that the reference mark can be detected by the controller. This
sometimes requires very low travel speeds.
– Set braking sufficiently high so that the motor controller does not overrun the targets
too much during search travel.
6.2.4 Secure zero point shift
Single-turn encoders that are set to permanently homed are already permanently homed on delivery.
The absolute zero point is stored by the manufacturer in the EEPROM of the encoder.
Note
Incorrect positioning of the axis.
Drives with absolute value encoders are always homed at switch-on to the absolute
encoder zero point stored in the encoder. For comparison between the homing point of
the current measuring reference system and the mounting-related absolute zero point
of the motor encoder, the resulting offset in the EEPROM of the encoder must be stored.
The value is used for conversion of the actual position measured by the encoder.
• Carry out homing first
• Observe the subsequent special features for saving the zero offset.
Multi-turn
Absolute value encoders supply directly after switch-on an absolute position that is unique throughout
the entire travel distance of an axis. Such an encoder is calibrated on the measuring reference system
one time through homing and through a position offset stored in the EEPROM of the encoder (saving
the zero point offset).