AXIS_REF

The AXIS_REF data type contains axis information. AXIS_REF is an interface between the PLC and the NC. It is added to MC function blocks as axis reference.

TYPE AXIS_REF :
VAR_INPUT
    PlcToNc AT %Q* : PLCTONC_AXIS_REF;
END_VAR
VAR_OUTPUT
    NcToPlc AT %I* : NCTOPLC_AXIS_REF;
    ADS            : ST_AdsAddress;
    Status         : ST_AxisStatus;
    DriveAddress   : ST_DriveAddress;
END_VAR
END_TYPE

AXIS_REF elements	Description
PlcToNc	Data structure which is cyclically exchanged between PLC and NC. Via this data structure the MC function blocks communicate with the NC and send control information from the PLC to the NC. This data structure is automatically placed in the output process image of the PLC and must be linked in TwinCAT System Manager with the input process image of an NC axis. (Type: PLCTONC_AXIS_REF)
NcToPlc	Data structure which is cyclically exchanged between PLC and NC. Via this data structure the MC function blocks communicate with the NC and receive status information from the NC. This data structure is automatically placed in the input process image of the PLC and must be linked in TwinCAT System Manager with the output process image of an NC axis. The NCTOPLC structure contains all main state data for an axis such as position, velocity and instruction state. Since data exchange takes place cyclically, the PLC can access the current axis state at any time without additional communication effort. (Type: NCTOPLC_AXIS_REF)
ADS	The ADS data structure contains the ADS communication parameters for an axis that are required for direct ADS communication. Normally this structure does not have to be populated. The user can use it to stored information for controlling an axis on another target system or via a special port number.
Status	Data structure containing additional or processed status information for an axis (type: ST_AxisStatus). This data structure is not refreshed cyclically, but has to be updated through the PLC program. For this purpose MC_ReadStatus or alternatively the action "ReadStatus" of AXIS_REF can be called:
DriveAddress	Data structure containing the ADS access data of a drive device. These data are not filled until the function block MC_ReadDriveAddress has been called implicitly or explicitly.

Sample:

VAR
 Axis1 : AXIS_REF (* axis data structure for Axis-1 *)
END_VAR

(* program code at the beginning of each PLC cycle *)
Axis1.ReadStatus();

(* alternative program code at the beginning of each PLC cycle *)
Axis1();

The call of "ReadStatus" or "Axis1" should be made once at the beginning of each PLC cycle. The current status information can then be accessed in AXIS_REF from the whole PLC program. Within a cycle the status does not change.

Requirements

Development environment	Target system type	PLC libraries to include
TwinCAT v3.0.0	PC or CX (x86 or x64)	Tc2_MC2