Delta Tau GEO BRICK LV User Manual

Turbo PMAC Family Overview 

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In any application, the Turbo PMAC will have software components provided both by Delta Tau and by 
the user.  The Delta Tau software components are known as the firmware (software embedded in the 
hardware).  These are not application-specific.  The user software components – primarily motion 
programs and PLC programs – are application-specific. 

The operational firmware of the Turbo PMAC serves as both the operating system for the controller and 
as the PMAC-language interpreter.  As an operating system, it provides a hard-real-time multi-tasking 
environment with extremely fast task switching, providing a very high level of determinism for the high-
priority tasks such as servo-loop closure.  It also handles the sequencing of operations within motion 
programs automatically, so this sequencing of move-by-move operations does not have to be handled by 
the user. 

Typically, the operational firmware is updated once or twice a year to add new features and to fix 
problems.  Field upgrades of the firmware are easy to perform.  Simply power up the Turbo PMAC with 
the firmware reload jumper installed, and then launch the PMAC Executive program on the PC.  The 
Executive program will notice automatically that the Turbo PMAC is ready to install new firmware and 
query for the file to be downloaded.  It will download the new firmware automatically from the specified 
file into the Turbo PMAC. 

The operation of the bootstrap firmware is invisible to virtually all Turbo PMAC users.  Its function is 
very similar to that of a PC’s BIOS, providing a link between the hardware and the operating system, and 
permitting the operating system to load.  While Delta Tau may upgrade the bootstrap firmware from time 
to time (and each new hardware configuration of the CPU may require a different variation of the 
bootstrap firmware), Delta Tau does not support the field upgrade of the bootstrap firmware. 

In normal operation, the bootstrap firmware operates invisibly underneath the operational firmware, 
automatically loading the operational firmware on top of it at each power-up/reset.  However, if the Turbo 
PMAC is powered up or reset with the firmware-reload jumper on, the operational firmware will not be 
loaded from flash memory, and the host computer can communicate directly with the bootstrap firmware 
(through the main serial port or a bus that uses the CPU’s host port only).  If the operational firmware has 
not been loaded, Turbo PMAC’s response to the ?, ??, or ??? status query command is BOOTSTRAP 
PROM. 

Motors, axes, and coordinate systems are software structures in a Turbo PMAC system.  While they 
usually utilize hardware channels to interface to the outside world, it is possible to use them as virtual 
structures, just for their computational features.   

Motors 

A motor in Turbo PMAC consists of the software structures necessary for basic moves, commanded-
position interpolation, servo-loop closure, commutation, and current-loop closure.  Every Turbo PMAC 
has the capability for executing the algorithms for 32 motors, even if only a few servo channels are 
provided.  These motors are specified by number (1 through 32), and their attributes are specified in terms 
of raw “counts”, milliseconds, and related units. 

A Turbo PMAC motor accesses hardware-channel functions for its various input and output needs 
through setup I-variables that contain the address of the register to be used.  This mapping functionality 
provides great power and flexibility in a simple manner.