Siemens SIMATIC FM 351 - Reference Point Approach Mode

Modes and Jobs
9-11
FM 351 Positioning Module
C79000-G7076-C351-02
9.3 Reference Point Approach Mode
Definition
With the “reference point approach” mode, you can synchronize the axis based on
a repeated external event.
Requirements
• An incremental encoder with zero marker.
• You have set the parameters for the axis.
Connection Channel 1 Channel 2
Reference-point switch Digital input 1I0 Digital input 2I0
The reference-point switch should be designed so that the drive
can brake reliably from rapid to creep speed in the region of the
switch.
Reversing switch Digital input 1I1 Digital input 2I1
When you set the parameters, make sure that the start of the
reference point approach is set in the direction of the reversing
switch. Only then can you be sure that the reference-point switch
is always found.
Enable input Digital input 1I2 Digital input 2I2
Sequence of the “Reference Point Approach” Mode
1. Enter the value for the reference point coordinate in the parameter DB
(REFPT).
2. Enter the type of “reference point approach” in the parameter DB.
Here, you have the following options:
Start in direction... For Synchronization use...
plus The first zero marker in the direction plus after
leaving the reference point switch
REFPT_TYPE=0
plus The first zero marker in the direction minus
after leaving the reference point switch
REFPT_TYPE=1
minus The first zero marker in the direction plus after
leaving the reference point switch
REFPT_TYPE=2
minus The first zero marker in the direction minus
after leaving the reference point switch
REFPT_TYPE=3