Specifications for C300^TM  Controller

The C-300^TM  Motion Controller provides up to three completely independent motor controllers on a half-size ISA-bus card. In addition to the motion control functions, 8 digital inputs and 5 digital outputs are provided for control and sensing functions.

Each axis has provision for two limit switches and a reference switch, in addition to a differential quadrature encoder input with index capabilities. For highest precision in a homing application, motion is commanded until the reference switch is encountered, then continues at a slower rate until the encoder index is found. With this procedure, the home position may be repeated to an accuracy of one encoder count, or the ultimate accuracy of the system.

All limit and reference switch inputs are sensed through line receivers with 1 volt of hysteresis for noise rejection. The encoder inputs use differential line receivers with 300 mv of hysteresis. They may be used with single encoders, as well.

A capture/compare circuit is used to sense any change in the state of the limit and reference switches. When any one of them changes, a maskable interrupt is generated. There are several additional sources of interrupt, including excessive error, encoder error index, and absolute and relative position breakpoints.

There are four ISA-bus interrupt lines which may be used for the C-300^TM  controller. Interrupts 10, 22, 12 and 15 may be used. Alternatively, all interrupts may be disabled and the state of the interrupt may be polled from the host processor.

An address switch is used to select the base address of the I/O space to be used for the C-300^TM . Eight addresses are used for accessing all functions. The address switch selects the base address. The individual functions are accessed at the listed offset from the base address which is set to address 320 at the factory.

LM629 Commands	0
LM629 Data	1
Interrupt register	2 (Read only)
Limit switch register	3 (Read only)
Configuration and output	6 (Read only)
Input register	6 (Read only)
Software reset	7 (Read only)

(Desired channel selected by configuration register bits 6, 7, address 6)

The C-300^TM  controller uses National Semiconductor LM629 integrated circuits to perform the servo control functions. If the user wishes to program them directly, the programming is done exactly as described in National's programming manual.  For those users wishing to use the C-300^TM  in an interactive manual mode, an MS-DOS program is supplied as well as a VisualBasic virtual instrument program and LabView drivers.