Siemens SIMATIC S7-1500 Function Manual page 139

Digital input, homing mark
In this field, select the PLC tag of the digital input, which should act as a homing mark
(reference cam).
In order to be able to select an input, a digital input module must have been added in the
device configuration, and the PLC tag name for the digital input must be defined.
Enable direction reversal at the hardware limit switch
Select this check box to use the hardware limit switch as a reversing cam for the home
position approach. After the axis has reached the hardware limit switch during active homing,
it is ramped down at the configured maximum deceleration rate and then reversed. The
home position switch is then sensed in reverse direction. If this function is not enabled and
the axis reaches the hardware limit switch during active homing, then the drive is disabled
and braked with the ramp configured in the drive.
Approach direction
Select the approach direction for seeking the homing mark.
"Positive" is the approach direction in the direction of positive position values; "negative" in
the direction of negative position values.
Homing direction
Select the direction in which the homing mark should be approached for homing.
Homing mark
Select the switch position of the "digital input" that is to be used as homing mark.
When a "digital input" is overshot, two switch edges which are spatially separated from one
another are generated. The selection of the positive or negative side ensures that the
homing mark is always evaluated based on the same mechanical position.
The positive side is the switch position with a greater position value; the negative side is the
switch position with the lesser position value.
The selection of the side is independent of the approach direction, and independent of
whether it causes a rising or falling edge.
Approach velocity
In this field, specify the velocity at which the "digital input" should be sought during the home
position approach. A possibly configured home position offset is traversed with the same
velocity.
Homing velocity
In this field, specify the velocity at which the axis approaches the home position for homing.
S7-1500 Motion Control V13 Update 3
Function Manual, 07/2014, A5E03879256-AC
6.6 Configuring the positioning axis/synchronous axis technology object
Configuring
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