Lenze PM94P01C - Manual (Page 60)

PM94P01C 58
Programming
2.15 Homing
2.15.1 What is Homing?
Predefined (firmware based) homing functionality is available on PositionServo drives with firmware 3.03 or later.
In addition custom homing functionality can be created by the programmer within the user program by utilizing the
programming command set available.
Examples of custom homing routine creation as well as user program code to replicate each of the predefined homing
routines is available from technical support.
Homing is the method by which a drive seeks the home position (also called the datum, reference point, or zero point).
There are various methods of achieving this using:
• limit switches at the ends of travel, or
• a dedicated home switch, or
• an Index Pulse or zero reference from the motor feedback device, or
• a combination of the above.
In order to use home methods involving Motor Index Pulse (zero pulse), the index pulse of the motor MUST be connected
to the drive registration input (C3). For encoder motors this connection can be made directly. Connect the 0V ref for the
encoder to P3-36 (IN_C_COM) and the Z+ line from the encoder to P3-39 (IN_C3).
For convenience of wiring and for Resolver motors the Z pulse output from the simulated encoder can be looped back
into the C3 registration input. Connect P3-36 (IN_C_COM) to the digital ground terminal P3-5 and P3-39 (IN_C3) to P3-
11 (BZ+). For Resolver motors the Z Pulse is created by the simulated encoder at 0 degrees of the motor shaft.
Establish the time period that the Z pulse must be present on the input in order for it to be reliably detected (back thru
C3), by calculating the maximum homing speed for the specific application. A 1kW pull-up resistor is available for those
with issues picking up the index pulse.
2.15.2 The Homing Function
The homing function provides a set of trajectory parameters to the position loop, as shown in Figure 22. They are
calculated based on user supplied variable values such as:
VAR_HOME_OFFSET
VAR_HOME_METHOD
VAR_HOME_SWITCH_INPUT
VAR_HOME_FAST_VEL
VAR_HOME_SLOW_VEL
VAR_HOME_ACCEL
VAR_START_HOMING
Trajectory
Parameter Position
Demand
Homing
Function
Trajectory
Generator Position
Loop
Home Offset
Homing Method
Homing Speeds
Home Velocity Fast/Slow
Homing Acceleration
Figure: 22: Homing Function
Homing Function Monitoring:
The extended drive status variable (#83 EXSTATUS variable) contains bit values for monitoring the homing function
over the communications interface.
Bit 21 of #83 indicates homing procedure in progress and is set to logic 1 while homing is being executed.
Bit 22 of #83 indicates homing complete. It is set to 1 upon the successful completion of the homing routine.