102BTechnology instructions
9.3 Basic motion control
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
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Table 9- 49 Velocity characteristics of MC homing
Operation
Notes
A
Approach velocity
B
Reduced velocity
C Home position coordinate
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D Home position offset
①
Search phase (blue curve segment): When active homing starts, the axis accelerates to the configured "approach
velocity" and searches at this velocity for the reference point switch.
②
Reference point approach (red curve section): When the reference point switch is detected, the axis in this example
brakes and reverses, to be homed on the configured side of the reference point switch at the configured "reduced
velocity".
③
Travel to reference point position (green curve segment): After homing at the reference point switch, the axis travels
to the "Reference point coordinates" at the "reduced velocity". On reaching the "Reference point coordinates", the
axis is stopped at the position value that was specified in the Position input parameter of the MC_Home instruction".
Note
If the homing search does not function as you expected, check the inputs assigned to the
hardware limits or to the reference point. These inputs may have had their edge interrupts
disabled in device configuration.
Examine the configuration data for the axis technology object of concern to see which inputs
(if any) are assigned for "HW Low Limit Switch Input", "HW High Limit Switch Input", and
"Input reference point switch". Then open the Device configuration for the CPU and examine
each of the assigned inputs. Verify the "Enable rising edge detection" and "Enable falling
edge detection" are both selected. If these properties are not selected, delete the specified
inputs in the axis configuration and select them again.