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Motion Control > Delta Tau

Delta Tau Motion Control

PMAC | PMAC 2 | PMAC-NC System Overview | Software

PMAC- Basic 4/8 Axis Programmable Multi-Axis Controller

PMAC2: Advancing State of the Art

What's New About PMAC2?

PMAC2 is the first motion controller to support all of the popular controller-to-drive interface standards, including:

PMAC2 brings speeds and resolutions to new levels:

Now you have a PMAC2 highly integrated controller!

Fully Digital Motor Control

PMAC2 is on the leading edge of this movement, with its capability to perform all of the required motion control tasks digitally -- trajectory planning, interpolation, position loop, velocity loop, motor phase commutation, and current loop -- and to directly command each transistor of the power stage with digital PWM commands. PWM frequency and deadtime are programmable and continuously variable.

Until recently, closing the motor current loops digitally was either impossible of prohibitively expensive, given the limitations of digital microprocessors and hardware. However, PMAC2's 40, 60, or 80 MHz digital signal processor (DSP) and 120 MHz, 45,000-gate ASIC permit multi-axis digital current loop control at a very reasonable price. In fact, total system cost can be lower with fully digital control, because the front-end circuitry of up to 8 amplifiers is replaced by a small amount of digital circuitry on the PMAC. Furthermore, modern digital control techniques can extract substantially improved performance out of existing power stages and motors.

MACRO Ring Network Interface

For many machine builders, particularly those designing large machines with drives distributed away from the controller, installing and maintaining the cabling has been a nightmare. Control manufacturers have recently introduced several "ring network" interfaces between the controller and drives the provide one single-strand connection for each drive. However, all of the approaches to date have involved both very high cost and significant performance limitations.

Delta Tau has used the latest in cutting-edge networking technology to produce MACRO (Motion And Control Ring Optical), a non-proprietary 125 Megabit per second optical ring network designed specifically for demanding motion control applications. No longer do performance compromises have to be made for the sake of cabling simplicity. And because it uses high-volume components designed for the office networking market, the price is very reasonable.

Still a Member of the PMAC Family

PMAC2 retains all of the features that made the PMAC family so popular for motion control. It keeps unchanged PMAC's powerful and flexible motion programming language, combining the trajectory commands of machine-tool code, and the math and logic of high-level computer languages. It also keeps PMAC's PLC programs, both interpreted and compiled, which provide for execution of many tasks asynchoronous to the programmed motion sequences with fulll access to all of PMAC's registers.

Other high performance features of PMAC retained on PMAC2 include:

PMAC2 is available in both PC bus form, with the PMAC2-PC occupying 1-1/2 slots for 8 axes, and the PMAC2-Lite occupying 1 slot for 4 axes, and in VME bus form, with the PMAC2-VME controlling up to 8 axes in a double VME slot. In addition, low-cost "Ultra-Lite" versions of the PMAC2, with the MACRO interface replacing the local axis interfaces, are available in VME an PC (late 1996) forms.

Summary Feature Comparison of PMAC and PMAC2

Feature PMAC PMAC2
Standard processor speed 20 MHz 40 MHz
Option processor speeds 40, 60, 80 MHz 60, 80 MHz
Standard memory speed 1 wait state 0 wait state
Option memory speed 0 wait state 0 wait state
Base # of encoder channels 4 6
Max # of on-board encoder channels 8 10
Max encoder count rate 20 MHz 40 MHz
Encoder digital delay filter Best 2-of-3 on A&B channels Best 2-of-3 on A,B, and Index channels
Analog feedback capability? With accessory board (ACC-28 or -36) With optional on-board ADCs (12-bit, 8 or 16 ch)
Resolver feedback capability? With accessory board (ACC-8D Opt 7) With accessory board (ACC-8D Opt 7)
Parallel-data feedback capability? With accessory board (ACC-14) 1 channel on-board, more with accessory board
MLDT (e.g. Temposonics) feedback capability? With accessory board (ACC-29), up to 8 channels On-board, up to 8 channels
MLDT timer frequency; resolution (no recirculation) 30 MHz; 0.09mm (3.6 mil) 120 MHz; 0.02mm (0.9 mil)
Position compare pulse specification Single-sided; software setup, hardware trigger (one count wide, or software turnoff) Double-sided; software setup, hardware trigger; auto-increment value
Maximum update rate of position compare register ~1kHz (user-programmed software update) 10 MHz (automatic hardware update)
Multiple compares on single encoder? No Yes, up to 4 compares on ENC1 and ENC5
Separate User flag for position capture? No Yes
Gated index pulse (one quadrature state wide) for position capture? No Yes
Digital delay filter on flag inputs? No Yes, best 2-of-3 on all flag inputs
Flag hardware interface Sinking only Sinking of sourcing
Output DAC resolution 16 bits To 18 bits, programmable
Base # of DAC channels 4 8 (with analog output version)
Max # of on-board DAC channels 8 16 (with analog output version)
Location of DACs On-board On interface board
Input resolution from off-board serial ADCs 16 bits To 18 bits, programmable
Base # of interfaces to serial ADCs 4 8
Max # of interfaces to serial ADCs 16 16
Pulse and direction (PFM) outputs? With accessory; uses DAC channel on PMAC On board, direct digital generation; does not use DAC channel
Pulse-width-modulated outputs? No Yes, 3 top-and-bottom pairs per axis, with programmable frequency and deadtime.
Interface to analog velocity-mode amplifiers? Yes Yes
Interface to analog torque-mode amplifiers Yes Yes
Interface to analog sinusoid-input amplifiers? Yes Yes
Interface to direct digital PWM-input amplifiers No Yes
Digital current loop capability? No Yes
Dedicated control panel port? Yes No
Dual-ported RAM Optional, on separate board Optional, on main board
Max # of on-board A/D converters 1 (thru V/F converter, 10 bit resolution) 16 12-bit converters
     
Method for setting clock rates (encoder, DAC, ADC, phase, servo) Hardware jumpers Software registers (re-initialization jumper forces to default)
Method for setting baud rate Hardware jumpers Software register (re-initialization jumper forces to default)
Method for setting card # on serial multi-drop cable Hardware jumpers 1 jumper (Card 0 or not); software register

PMAC-NC System Overview

Delta Tau offers a wide range of supporting hardware for the machine tool retrofitter and O.E.M.. Complete controller packages, known as "PMAC-NC Machining Center Controllers" (they function equally well for lathes) are available. This complete machine tool controller package provides the user a specially designed industrial package for the rigors of real CNC machine shop environment. The following lists the standard features of the PMAC-NC Machining Center controller:

PMAC-NC Machining Center Controller Hardware Component List

PMAC-Lite, 4 Axis, 20 MHz Board Microsoft Windows 95
16 Meg Ram 15" SVGA Monitor
Pentium Based Motherboard Industrial Mouse
500 Meg Hard Drive PMAC-NC for Windows, Version 1.6 Software
3.5 High Density Floppy Disk 101 Membrane Keyboard
1 Meg Ram Video Card Emergency Stop Pushbutton
IDE Controller Card Encoder Interface Terminal Board
1 Serial, 1 Parallel Port

PMAC-NC Machining Center Controller Pushbuttons

Cycle Start Cooling Mist
Feedhold Coolant Flood
Reset Optional Stop
Drawbar Clamp Jog +
Single Block Jog -
Block Delete

PMAC-NC Machining Center Controller Operator Control Panel

Axis Select Rotary Switch Spindle Direction Select Rotary Switch
Jog Select Rotary Switch On Pushbutton
Mode Select Rotary Switch Off Pushbutton
Feedrate Override Rotary Switch Machine Keylock
Rapid Override Select Rotary Switch Manual Pulse Generator
Spindle Speed Override Select Rotary Switch On-Board O/O Driver For An Additional 32 Inputs & 32 Outputs
Speed/Multiply Select Rotary Switch

The unique aspect of Delta Tau's approach to the machine tool business is that we don't force you to buy all the components from us. Unlike many of our competitors, Delta Tau does not force you to buy the controller, amplifiers, and motors all from one closed source. You can buy just those pieces of the system from Delta Tau that makes sense for your particular application, and the rest from other suppliers.


PMAC-NC for Windows Standard Software Feature List

Program Check Screen Real Time Servo Plotting Screen
G Code Program Text Buffer Built In Video Interfacing
Program Rewind PMAC &I/O Diagnostics Screen
Inch/Metric Display Machine Message Screen
Windows Based File Loading Software Operators Control Panel
Built In PMAC-NC for Windows Help Files Solid Modeling Tool Verification Program
Automatic Work Fixture Settings Screen Configurable G & M Codes
Parts Required And Parts Total Counter Feedrate Information Display
Automatic Tool Settings Screen Spindle Information Display
Built In Time & Date Clock Cycle Time & Cycle Total Counters
Built In Background Program Editor With Save, Search, Cut, Copy, Paste, Clear & Undo Ability To Launch Third Party Software From Within The PMAC-NC for Windows program
Five Position Screens (Program, Operator, Machine, Distance To Go, & Overall Position

PMAC® communications have never been this easy

HMI screenExecutive Programs for Development:

Programming Libraries:

Setup Programs (Step by Step Tutorials):