User's Manual

PMAC User Manual
Introduction 1
INTRODUCTION
The Delta Tau Data Systems, Inc. Programmable Multi-Axis Controller (PMAC) is a family of high-
performance servo motion controllers capable of commanding up to eight axes of motion simultaneously
with a high level of sophistication. Through the power of a Digital Signal Processor (DSP), PMAC offers a
price-performance ratio for multi-axis control that was not previously available. Motorola’s DSP56001 is
the CPU for PMAC, and it handles all the calculations for all eight axes.
There are four hardware versions of PMAC: the PMAC PC, the PMAC Lite, the PMAC VME, and the
PMAC STD. These cards differ from each other in their form factor, the nature of the bus interface, and in
the availability of certain I/O ports. All versions of the card have identical on-board firmware, so PMAC
programs written for one version will run on any other version. The PMAC STD has a different memory
mapping of some I/O.
Any version of PMAC may run as a standalone controller, or it may be commanded by a host computer,
either over a serial port or over a bus port.
Flexibility
As a general purpose controller, PMAC can serve in a wide variety of applications, from those requiring
sub-micro inch precision to those needing hundreds of kilowatts or horsepower. Its diverse uses include
robotics, machine tools, paper and lumber processing, assembly lines, food processing, printing, packaging,
material handling, camera control, automatic welding, silicon wafer processing, laser cutting, and many
others.
Configuration for a Task
PMAC is configured for a particular application by choice of the hardware set (through options and
accessories), configuration of parameters, and the writing of motion and PLC programs. Each PMAC
possesses firmware capable of controlling eight axes. The eight axes can be associated all together for
completely coordinated motion; each axis can be put in its own coordinate system for eight completely
independent operations; any intermediate arrangement of axes into coordinate systems is also possible.
The PMAC CPU communicates with the axes through specially designed custom gate array ICs, referred to
as DSPGATES. Each of these ICs can handle four analog output channels, four encoders as input, and four
analog-derived inputs from accessory boards. One PMAC can utilize from one to four of these gate array
ICs, so specifying the hardware configuration amounts to counting the numbers and types of inputs and
outputs. Up to 16 PMAC may be ganged together with complete synchronization, for a total of 128 axes.
PMAC is a Computer
It is important to realize that PMAC is a full computer in its own right, capable of standalone operation
with its own stored programs. Furthermore, it is a real-time, multitasking computer that can prioritize tasks
and have the higher priority tasks pre-empt those of lower priority (most personal computers are not
capable of this). Even when used with a host computer, the communications should be thought of as those
from one computer to another, not as computer to peripheral. In these applications, the ability of to run
multiple tasks simultaneously, properly prioritized, can take a tremendous burden off the host computer
(and its programmer), both in terms of processor time, and of task-switching complexity.