MC_Power: Enable, disable axis as of V6 (S7-1200) - Motion Control

S7-1200 Motion Control (S7-1200)
ft:publication_title
S7-1200 Motion Control (S7-1200)
Product
Motion Control
Version
V20
Publication date
11/2024
Language
en-US
MC_Power: Enable, disable axis as of V6

Description

The Motion Control instruction "MC_Power" enables or disables an axis.

Requirements

  • The technology object has been configured correctly.

  • There is no pending enable-inhibiting error.

For PROFIdrive drive or analog drive connection:

  • Cyclic BUS communication is established between controller and encoder ("<Axis name> .StatusSensor[1].CommunicationOK" = TRUE).

  • Cyclic BUS communication is established between controller and drive ("<Axis name> .StatusDrive.CommunicationOK" = TRUE).

Override response

Execution of "MC_Power" cannot be aborted by a Motion Control command.

Disabling the axis (input parameter "Enable" = FALSE) aborts all Motion Control commands for the associated technology object in accordance with the selected "StopMode".

Parameters

Parameter

Declaration

Data type

Default value

Description

Axis

INPUT

TO_Axis

-

Axis technology object

Enable

INPUT

BOOL

FALSE

TRUE

The axis is enabled.

FALSE

All current jobs are interrupted in accordance with the "StopMode" configured. The axis is stopped and disabled.

StartMode

INPUT

INT

1

0

Enable positioning axis not position-controlled *)

1

Enable positioning axis position-controlled *)

*) This parameter is ignored when a positioning axis with PTO (Pulse Train Output) drive is used.

The parameter initially takes effect when the positioning axis is enabled (Enable changes from FALSE to TRUE) and when the axis is enabled after successful acknowledgment of an interrupt that caused the axis to be disabled.

StopMode

INPUT

INT

0

0

Emergency stop

If a request to disable the axis is pending, the axis brakes at the configured emergency deceleration. The axis is disabled after reaching standstill.

1

Immediate stop

If a request to disable the axis is pending, this setpoint zero is output and the axis is disabled. The axis is braked depending on the configuration in the drive, and is brought to a standstill.

With drive connection via PTO (Pulse Train Output):
When you disable the axis, the pulse output is stopped with a frequency-dependent deceleration:

  • Output frequency ≥ 100 Hz

    Deceleration: max. 30 ms

  • Output frequency < 100 Hz

    Deceleration: 30 ms up to max. 1.5 s at 2 Hz

2

Emergency stop with jerk control

If a request to disable the axis is pending, the axis brakes at the configured emergency deceleration. If the jerk control is activated, the configured jerk is taken into account. The axis is disabled after reaching standstill.

Status

OUTPUT

BOOL

FALSE

Status of axis enable

FALSE

The axis is disabled.

The axis does not execute Motion Control commands and does not accept any new commands (exception: MC_Reset command)

For drive connection via PTO (Pulse Train Output):

The axis is not homed.

Upon disabling, the status does not change to FALSE until the axis reaches a standstill.

TRUE

The axis is enabled.

The axis is ready to execute Motion Control commands.

Upon axis enabling, the status does not change to TRUE until the signal "Drive ready" is pending. If the "Drive ready" drive interface was not configured in the axis configuration, the status changes to TRUE immediately.

Busy

OUTPUT

BOOL

FALSE

TRUE

MC_Power" is active.

Error

OUTPUT

BOOL

FALSE

TRUE

An error occurred in Motion Control instruction "MC_Power" or in the associated technology object. The cause of the error can be found in parameters "ErrorID" and "ErrorInfo".

ErrorID

OUTPUT

WORD

16#0000

Error ID for parameter "Error"

ErrorInfo

OUTPUT

WORD

16#0000

Error info ID for parameter "ErrorID"

Note

If the axis is switched off due to an error, it will be enabled again automatically after the error has been eliminated and acknowledged. This requires that the input parameter "Enable" has retained the value TRUE during this process.

Enabling an axis with configured drive interface

To enable the axis, follow these steps:

  1. Check the requirements indicated above.

  2. Initialize input parameters "StartMode" and "StopMode" with the desired value. Set the input parameter "Enable" to TRUE.

    The enable output for "Drive enabled" changes to TRUE to enable the power to the drive. The CPU waits for the "Drive ready" signal of the drive.

    When the "Drive ready" signal is available at the configured ready input of the CPU, the axis is enabled. The output parameter "Status" and the variable of the technology object <axis name>.StatusBits.Enable indicate the value TRUE.

Enabling an axis without configured drive interface

To enable the axis, follow these steps:

  1. Check the requirements indicated above.

  2. Initialize input parameters "StartMode" and "StopMode" with the desired value. Set the input parameter "Enable" to TRUE. The axis is enabled. The output parameter "Status" and the variable of the technology object <axis name>.StatusBits.Enable indicate the value TRUE.

Disabling an axis

To disable an axis, you can follow the steps described below:

  1. Bring the axis to a standstill.

    You can identify when the axis is at a standstill in the variable of the technology object <axis name>.StatusBits.StandStill.

  2. Set input parameter "Enable" to FALSE after standstill is reached.

  3. If output parameters "Busy" and "Status" and variable of technology object <axis name>.StatusBits.Enable indicate the value FALSE, disabling of the axis is complete.