Aerotech UNIDEX 600 Series, Руководство пользователя

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Introduction and Overview U600 User’s Guide
1-6
Aerotech, Inc
. Version 1.4
1.5. Motion
This section summarizes the basic features of motion generated by the U600 controller.
1.5.1. The Servo Loop
Translated into velocity and position commands are the programmer’s commands. The
controller obtains a new velocity and position command every millisecond. These
commands are input to the servo loop, which generates the motor torque signals sent out
to the amplifiers. The servo loop is responsible for reading the commands and the
feedback (the actual position and speeds) and adjusting the motor torques in order to
reduce the position and velocity errors. The definition of error is commanded minus the
actual.
The servo loop normally operates off of a 1/4 millisecond interrupt. However, the user
can slow this interrupt down to 1 millisecond, with the Enable1KhtzServo global
parameter. This action may be necessary if there is too much processing off the interrupt
potentially starving the forever loop (see Section 1.4.1).
The settings of various axis parameters adjust or tune the servo loop activity. Section 5.3
of Chapter 5: AerTune, summarizes the relevant axis parameters and their use.
1.5.2. Generating Motion
In general there are three types of motion available for a single axis: synchronous,
asynchronous, and master-slave (sometimes called camming). Please see the appropriate
programming manual, (EDU156 for the library interface, and EDU158 for the CNC
interface) for complete details on how to invoke these types of motion, the rest of this
section summarizes this information.
Table 1-2. Available Motion Types
Motion Type Library Interface Access CNC Interface Access
Synchronous NONE AVAILABLE G0, G1, etc. CNC commands
Asyncronous AerMovexxx() functions STRM etc. CNC commands
Cam table AerCamTablexxx() function NONE AVAILABLE
When executing synchronous motion, the controller does not move to the next step in the
program until the motion finishes and the axes are in the commanded position.
In asynchronous motion, the motion is initiated, but the controller immediately moves to
the next step in the program. The controller does not wait for the motion to complete.
Asynchronous motion offers more versatility, allowing the user to perform other tasks
during a time consuming move. However, asynchronous moves are potentially more
dangerous, since the programmer is responsible for making sure that the first move