Seek-Reference-Point Operating Mode - Siemens SIMATIC FM 351 Installation Manual

Operating Modes and Settings
9.3
Definition
Requirements
9
Reference-point switch
Reversing switch
Enable input
9-6

Seek-Reference-Point Operating Mode

You synchronize the FM 351 with the Seek-reference-point mode.
Synchronization with a seek-reference-point traverse is only necessary with
incremental encoders. A seek-reference-point traverse must be carried out for
each channel.
The synchronization of pulse counters and the axis is necessary:
So that your drive can approach an absolute target.
So that your drive can traverse a relative displacement in a defined range.
Because, for example, the reference point is lost after a POWER-ON.
Please take note of the following requirements for the seek-reference-point
mode:
The channel for which a seek-reference-point mode is to be carried out,
must be parameterized.
You have defined in the machine data:
– The type of seek-reference-point mode.
– The start speed for a seek-reference-point mode.
Note
The following applies for a rotary axis: The reproducibility of the reference
point is only guaranteed if an integer ratio exists between the increment val-
ues for the value End of rotary axis and the value Displacement per en-
coder revolution.
Connection
On digital input 1I0
The reference-point switch must be designed such that in the region of the switch the
drive can brake reliably from rapid to creep speed.
On digital input 1I1
During parameterization ensure that the start of the seek-reference-point traverse is para-
meterized in the direction of the reversing switch. It is only by doing this that you can be
sure that the reference-point switch is always found.
On digital input 1I2
Channel 1
On digital input 2I0
On digital input 2I1
On digital input 2I2
Channel 2
FM 351 Positioning Function Module
EWA 4NEB 720 6001-02