Siemens S7-1200 - Motion Control Instructions; MC Instruction Overview

Technology instructions
9.3 Motion control
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
455
9.3.5
Motion control instructions
9.3.5.1
MC instruction overview
The motion control instructions use an associated technology data block and the dedicated
PTO (pulse train outputs) of the CPU to control the motion on an axis.
● MC_Power (Page 456) enables and disables a motion control axis.
● MC_Reset (Page 459) resets all motion control errors. All motion control errors that can
be acknowledged are acknowledged.
● MC_Home (Page 460) establishes the relationship between the axis control program and
the axis mechanical positioning system.
● MC_Halt (Page 462) cancels all motion processes and causes the axis motion to stop.
The stop position is not defined.
● MC_MoveAbsolute (Page 464) starts motion to an absolute position. The job ends when
the target position is reached.
● MC_MoveRelative (Page 466) starts a positioning motion relative to the start position.
● MC_MoveVelocity (Page 468) causes the axis to travel with the specified speed.
● MC_MoveJog (Page 471) executes jog mode for testing and startup purposes.
● MC_CommandTable (Page 473) runs axis commands as a movement sequence.
● MC_ChangeDynamic (Page 476) changes Dynamics settings for the axis.
● MC_WriteParam (Page 478) writes a select number of parameters to change the
functionality of the axis from the user program.
● MC_ReadParam (Page 480) reads a select number of parameters that indicate the
current position, velocity, and so forth of the axis defined in the Axis input.
CPU firmware levels
If you have an S7-1200 CPU with V4.0 firmware, select the V4.0 version of each motion
instruction.
If you have an S7-1200 CPU with V3.0 or earlier firmware, select the applicable V3.0, V2.0,
or V1.0 version of each motion instruction.
Note
The CPU calculates motion tasks in "slices" or segments of 10
ms. As one slice is being
executed, the next slice is waiting in the queue to be executed. If you interrupt the motion
task on an axis (by executing another new motion task for that axis), the new motion task
may not be executed for a maximum of 20
ms (the remainder of the current slice plus the
queued slice).