Reference Manual

Turbo PMAC/PMAC2 Software Reference
Introduction 21
INTRODUCTION
What is Turbo PMAC?
The Turbo PMAC is the newest addition to the renowned PMAC family of motion controllers. The
Turbo refers to a new high-performance CPU section that can be used with existing PMAC or PMAC2
interface circuitry to turbo-charge the application.
The Turbo PMAC is currently available in six versions:
 Turbo PMAC PC: PMAC servo interface circuitry, PC (ISA) bus interface
 Turbo PMAC VME PMAC servo interface circuitry, VME bus interface
 Turbo PMAC2 PC PMAC2 servo interface circuitry, PC (ISA) bus interface
 Turbo PMAC2 VME PMAC2 servo interface circuitry, VME bus interface
 Turbo PMAC2 PC Ultralite MACRO servo interface circuitry, PC(ISA) bus interface
 Turbo PMAC2 3U (UMAC Turbo and 3U Turbo Stack)
PMAC2 servo interface circuitry, PC/104 bus interface
Each of these versions has its own Hardware Reference manual.
More versions will be available in the near future.
What is New about Turbo PMAC?
The Turbo PMAC uses the increased speed and memory of the newest generation of digital signal
processing (DSP) ICs to enhance the capabilities of the PMAC family. The Turbo PMAC has the
software capability to control 32 axes in 16 independent coordinate systems, up from eight axes in eight
coordinate systems for the standard PMAC.
Many users will find the Turbo PMAC a very powerful and cost-effective solution when controlling large
numbers of axes. Remember that a PMAC board itself has at most eight servo interface channels; the
actual control of more than eight physical axes will require the use of either Acc-24 family axis expansion
boards, or remote interface circuitry on the MACRO ring.
The extra software axis capability can be useful for virtual axes which do not require (full) physical
hardware interface circuitry. Virtual axes have many important uses, including:
 Phantom coordinate systems in tool tip coordinates for inverse kinematics
 Virtual masters to replace mechanical line-shaft masters
 Redundant axes for error checking and recovery purposes
 Cascaded servo loops for hybrid control techniques (e.g. force and position)
Many other users will find the Turbo PMAC valuable even if less than eight axes are used, just because of
the additional computational speed. The DSP of the base version of the Turbo PMAC runs at 80 MHz,
but because operations on internal registers (about half of all operations) run in one clock cycle instead of
the two clock cycles required for the standard PMAC, performance is equivalent to that of a 120 MHz
standard PMAC.
The additional memory addressing capability of the Turbo PMAC permits the use of more axes and
coordinate systems, and more features for it. It also supports more variables, and (optionally) much larger
user buffer spaces.