Siemens SIMATIC S7 System Manual page 374

102BTechnology instructions
9.3 Basic motion control
Parameter
Reduced velocity
(Active homing only)
Home position offset
(Active homing only)
Table 9- 48 Factors that affect homing
Configuration
Approach direction
Positive
Positive
Negative
Negative
Sequence for active homing
You start active homing with motion control instruction "MC_Home" (input parameter
Mode = 3). Input parameter "Position" specifies the absolute reference point coordinates in
this case. Alternatively, you can start active homing on the control panel for test purposes.
The following diagram shows an example of a characteristic curve for an active reference
point approach with the following configuration parameters:
● "Approach direction" = "Positive approach direction"
● "Reference point switch" = "Right (positive) side"
● Value of "home position offset" > 0
374
Description
Specify the velocity at which the axis approaches the reference point switch for
homing.
Limit values (independent of the selected user unit):
Start/stop velocity ≤ reduced velocity ≤ maximum velocity
If the desired reference position deviates from the position of the reference point
switch, the home position offset can be specified in this field.
If the value does not equal 0, the axis executes the following actions following
homing at the reference point switch:
1. Move the axis at reduced velocity by the value of the home position offset.
2. When the position of the home position offset is reached, the axis position is set
to the absolute reference position. The absolute reference position is specified via
parameter "Position" of motion control instruction "MC_Home".
Limit values (independent of the selected user unit):
-1.0e12 ≤ home position offset ≤ 1.0e12
Influencing factors:
Configuration
Reference point switch
"Left (negative) side"
"Right (positive) side"
"Left (negative) side"
"Right (positive) side"
Current travel direction
Positive direction
Negative direction
Positive direction
Negative direction
Positive direction
Negative direction
Positive direction
Negative direction
System Manual, 11/2011, A5E02486680-05
Result:
Homing on
Reference point switch
Left
Right
Right
Left
Right
Left
Left
Right
S7-1200 Programmable controller