MC_ReadStatus

MC_ReadStatus

MC_ReadStatus determines the current operating state of an axis and signals it at the block outputs.

The updated operating state is additionally stored in the Status output data structure and in the Axis.Status axis data structure. This means the operating state only has to be read once at the start of each PLC cycle and can then be accessed via Axis.Status.

Notice: The Axis variable (type AXIS_REF) already includes an instance of the function block MC_ReadStatus. This means that the operating state of an axis can be updated at the start of a PLC cycle by calling up Axis.ReadStatus.

Example:

PROGRAM MAIN
VAR
   Axis1   : AXIS_REF
END_VAR
 
(* call the read status function *)
Axis1.ReadStatus;
 

Inputs

VAR_INPUT
   Enable  : BOOL;
END_VAR
 

Enable

The operating state of the axis is updated with each call of the block, as long as Enable is TRUE.

General rules for MC function blocks

Outputs

VAR_OUTPUT
   Valid               : BOOL;
   Busy                : BOOL;
   Error               : BOOL;
   ErrorId             : UDINT;
   (* motion control statemachine states: *)
   ErrorStop           : BOOL;
   Disabled            : BOOL;
   Stopping            : BOOL;
   StandStill          : BOOL;
   DiscreteMotion      : BOOL;
   ContinuousMotion    : BOOL;
   SynchronizedMotion  : BOOL;
   Homing              : BOOL;
   (* additional status *)
   ConstantVelocity    : BOOL;
   Accelerating        : BOOL;
   Decelerating        : BOOL;
   (* status data structure *)
   Status              : ST_AxisStatus;
END_VAR
 

Valid	Indicates that the axis operating state indicated at the other outputs is valid.
Busy	Indicates that the function block is active.
Error	Becomes TRUE if an error occurs.
ErrorID	If the error output is set, this parameter supplies the error number
ErrorStop	Axis status according to the PlcOpen state diagram
Disabled	Axis status according to the PlcOpen state diagram
Stopping	Axis status according to the PlcOpen state diagram
StandStill	Axis status according to the PlcOpen state diagram
DiscreteMotion	Axis status according to the PlcOpen state diagram
ContinousMotion	Axis status according to the PlcOpen state diagram
SynchronizedMotion	Axis status according to the PlcOpen state diagram
Homing	Axis status according to the PlcOpen state diagram
ConstantVelocity	The axis is moving with constant velocity
Acceleration	The axis accelerates.
Decelerating	The axis decelerates.
Status	Extended status data structure with additional status information.

General rules for MC function blocks

Inputs/outputs

VAR_IN_OUT
   Axis    : AXIS_REF;
END_VAR
 

Axis	Axis data structure

The axis data structure of type AXIS_REF addresses an axis uniquely within the system. Among other parameters it contains the current axis status, including position, velocity or error status.