Process image of an NC axis
The process image of an axis is used to connect it to different drive components. In the simplest case, a link is established between the axis and the drive and the necessary links between the process images are made automatically. In individual cases, in particular when unknown hardware components are integrated in the system, these links must be established manually. To this end, the process image of an NC axis is described in the following.
Notice | |
The data structures described here form an internal interface between NC drivers and connected drive hardware. This interface is constantly under development and can change in the future. |
Encoder process image of an axis
Various encoder hardware or the corresponding Bus Terminals for detecting the position of an axis are connected via the encoder process image (cyclic data exchange). Insofar as this hardware is directly supported by the system, no manual configuration of individual variables is necessary.
Input data to the encoder process image of an axis
I/O variable | Description | Remark |
|---|---|---|
nInData1 | Current actual position of the encoder or the drive in increments. The incremental value is processed by the NC and converted to the actual position in physical units, e.g. mm or degrees. Overflows of the incremental values are also counted by the NC. The system normally makes no distinction between incremental and absolute encoders (see also encoder parameter Reference System INC/ABS). | Unit: increments [INC] |
nInData2 | Optional actual latch position of the encoder or the drive in increments. The incremental value is processed by the NC and converted to the actual position in physical units, e.g. mm or degrees. TcMc.lib). | Unit: increments [INC] |
nStatus1 | Optional status information e.g.: Participant in Data Exchange, Encoder Error, communication to Position Latch or Register Communication. | This information depends on the type of encoder or drive. |
nStatus2 | Additional optional status information e.g.: Communication to Position Latch, communication Encoder Reset, communication to Read an Absolute Position | This information depends on the type of encoder or drive. |
nStatus3 | reserved |
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nStatus4 | Optional field bus-dependent IO status such as WcState (Working Counter) in the case of EtherCAT or CdIState in the case of Beckhoff Lightbus. | Meaning: |
Output data from the encoder process image of an axis
I/O variable | Description | Remark |
|---|---|---|
nOutData1 | Current actual position of the encoder or drive in increments, which the NC copies directly from the input variable nInData1 to the output variable nOutData1. | Unit: increments [INC] |
nOutData2 | reserved |
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nCtrl1 | Optional control information e.g.: Communication to Position Latch, communication Encoder Reset, Register Communication | This information depends on the type of encoder or drive. |
nCtrl2 | Additional optional control information e.g.: Communication to Position Latch, communication Encoder Reset, communication to Read an Absolute Position | This information depends on the type of encoder or drive. |
nCtrl3 | reserved |
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nCtrl4 | reserved |
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Drive process image of an axis
Various drive hardware or the corresponding Bus Terminals (+/- 10V, PWM etc.) are connected via the drive process image. Insofar as this hardware is directly supported by the system, no manual configuration is necessary.
Input data to the drive process image of an axis
I/O variable | Description | Remark |
|---|---|---|
nInData1 | reserved |
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nInData2 | reserved |
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nStatus1 | Optional status information e.g.: Drive Error, Drive Enable/Disable, Communication Drive State Machine (e.g. EtherCAT, SERCOS, CANopen, Profibus), Register Communication. | This information depends on the type of drive. |
nStatus2 | Additional optional status information e.g.: Drive Error, Drive Enable/Disable, Communication Drive State Machine (e.g. EtherCAT, SERCOS, CANopen, Profibus), Register Communication. | This information depends on the type of drive. |
nStatus3 | reserved |
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nStatus4 | Optional field bus-dependent IO status such as WcState (Working Counter) in the case of EtherCAT or CdIState in the case of Beckhoff Lightbus. | Meaning: |
Output data from the drive process image of an axis
I/O variable | Description | Remark |
|---|---|---|
nOutData1 | Current set velocity or current set position in increments. The set velocity or set position of the NC in physical units, e.g. mm or degrees, is mathematically converted back to an incremental value by the NC and transferred to the drive. Overflows of the incremental value are hereby taken into account by the NC in the set position. Depending on the type of drive, a standardization of the set velocity or set position is carried out in increments. If the drive type Universal Drive has been selected, nOutData1 contains the overall velocity (incl. position control part) with sign. | This information depends on the type of drive. |
nOutData2 | Current set velocity or current set position in increments. The set velocity or set position of the NC in physical units, e.g. mm or degrees, is mathematically converted back to an incremental value by the NC and transferred to the drive. Overflows of the incremental value are hereby taken into account by the NC in the set position. Depending on the type of drive, a standardization of the set velocity or set position is carried out in increments. If the drive type Universal Drive has been selected, nOutData2 contains the value of the overall velocity (incl. position control part, without sign). | This information depends on the type of drive. |
nCtrl1 | Optional control information: e.g.: Drive Reset, Drive Enable/Disable, Communication Drive State Machine (e.g. EtherCAT, SERCOS, CANopen, Profibus), Register Communication. | This information depends on the type of drive. |
nCtrl2 | Additional optional control information: Digital direction output of the setpoint generator (corresponds to the sign of the set velocity, hence without position controller) Digital Outputs Setpoint Generator: | This information depends on the type of drive |
nCtrl3 | Additional optional control information: Digital direction output or drive stages of the overall output (sum of the setpoint generator and the position controller) Digital Outputs (Setpoint Generator + Position Controller): |
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nCtrl4 | reserved |
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