Homing; Brief Description - Siemens SIMATIC S7-1500 Function Manual

3.14

Homing

3.14.1

Brief description

With homing, you create the relationship between the position in the technology object and
the mechanical position. The position value in the technology object is assigned to a homing
mark at the same time. This homing mark represents a known mechanical position.
With incremental actual values this process is called homing; with absolute actual values it is
called absolute value adjustment.
Homing is a requirement for the indication of the correct position in the technology object,
and for absolute positioning.
Homing is enabled with the Motion Control instruction "MC_Home", and is enabled for a
single homing process each time.
Homing status
The technology object tag <TO>.StatusWord.X5 (HomingDone) indicates whether the
technology object has been homed to an axis or external encoder.
Type of homing
Homing can occur by means of an independent movement for homing (active homing), by
means of a homing mark during an application-initiated movement (passive homing), or by
means of direct position assignment.
A distinction is made between the following types of homing:
● Active homing
● Passive homing
● Direct homing
● Absolute value adjustment
S7-1500 Motion Control V13 Update 3
Function Manual, 07/2014, A5E03879256-AC
Active homing initiates a homing movement and performs the necessary approach to the
homing mark. When the homing mark is detected, the actual position is set to the
configured value. It is possible to specify an offset from the home position.
When active homing starts, current traversing movements are aborted. The offset is
automatically traversed after the approach to home position.
The homing job does not perform its own homing motion. When the homing mark is
detected during an application-initiated motion, the actual position is set to the configured
value.
Passive homing is also called homing on the fly.
The homing job directly sets the actual position to the configured value, or offsets it by
this amount.
Absolute value adjustment adjusts the position of the technology object to the existing
absolute actual value.
Basics
3.14 Homing
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