MC_Home (motion control home)

The MC_Home instruction commands the axis to perform the
<search home>
 sequence. The details of this sequence are manufacturer dependent and can be set by the axis parameters. The Position input is used to set the absolute position when a reference signal is detected, and the configured Home offset is reached.
Operation details:
  • After MC_Power is issued, the axis Homed status is reset to 0 (not homed). In most cases, after the axis is powered on, the MC_Home function block needs to be executed to calibrate the axis position and the Home reference.
  • The MC_Home function block can only be canceled using a MC_Stop or a MC_Power function block. If it is canceled before it completes, the previously searched Home position is considered not valid and the axis Homed status is cleared.
Languages supported: Function block diagram, ladder diagram, structured text.
This instruction applies to the L50E and L70E controllers that support motion control.
MC_Home
MC_Home
MC_Home parameters
Parameter
Parameter Type
Data Type
Description
EN
Input
BOOL
Instruction block enable.
  • TRUE: Execute current MC_Home computation.
  • FALSE: There is no computation.
Applies only to ladder diagram programs.
AxisIn
Input
AXIS_REF
Use the AXIS_REF data type parameters to define AxisIn.
Execute
Input
BOOL
Indicates when to start motion.
  • TRUE: Start the motion at rising edge.
  • FALSE: Do not start motion.
Position
Input
REAL
Absolute position is set when the reference signal is detected and configured Home offset is reached.
The value range for this input is -0x40000000 – 0x40000000 physical pulse after the position is converted from user position unit to PTO pulse. Set the Position value within the Soft Limit.
An invalid input value results in an error. Error ID = MC_FB_ERR_PARAM.
HomingMode
Input
SINT
Enum input for Homing mode.
BufferMode
Input
SINT
Not used. The mode is always mcAborting.
ENO
Output
BOOL
Enable output.
Applies only to ladder diagram programs.
Axis
Output
Axis output is read-only in ladder diagram programs.
Done
Output
BOOL
  • TRUE: The Homing operation completed successfully and the axis state is set to Standstill.
  • FALSE: Homing operation is ongoing or incomplete.
Busy
Output
BOOL
  • TRUE: The instruction block is not finished.
  • FALSE: The instruction block is finished.
Active
Output
BOOL
TRUE: Indicates that the instruction block has control on the axis.
CommandAborted
Output
BOOL
TRUE: Command was overridden by another command, or error stop.
Error
Output
BOOL
Indicates an error occurred.
  • TRUE: An error is detected.
  • FALSE: No error.
ErrorID
Output
UNIT
A unique numeric that identifies the error. The errors for this instruction are defined in Motion control function block error IDs .
HomingMode parameters
Value
Name
Description
0x00
MC_HOME_ABS_SWITCH
Homing process by searching Home Absolute switch.
0x01
MC_HOME_LIMIT_SWITCH
Homing process by searching limit switch.
0x02
MC_HOME_REF_WITH_ABS
Homing process by searching Home Absolute switch plus using encoder reference pulse.
0x03
MC_HOME_REF_PULSE
Homing process by searching limit switch plus using encoder reference pulse.
0x04
MC_HOME_DIRECT
Static homing process with direct forcing a home position from user reference. The function block will set current position the mechanism is in as home position, with its position determined by the input parameter "Position".

MC_Home examples

MC_Home function block diagram example
MC_Home function block diagram example
MC_Home ladder diagram example
MC_Home ladder diagram example
MC_Home structured text example
MC_Home structured text example
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