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ORION ServoWire
Architecture
ServoWire System At a Glance
-
 High
speed serial bus operates at 200 Mbps (megabits per second)
- Isochronous communications guarantee
consistent loop updates (2kHz for eight servos; 4kHz for four servos)
- Asynchronous communications used to
manage command and status communications on bus.
- By using True Plug N Play functionality,
no computer is needed to configure new or replacement servodrives.
- Thin, inexpensive serial cables replace
bulkier interfaces and provide an all-digital interface.
All-Digital, Scalable
Architecture
The combination of ORION®
Industrial PC-based controllers and the ServoWire® network provides a
unique and effective architecture for automation control systems.
Most importantly, it provides compelling
benefits for servo-driven automation:
- All-Digital Operation: All drive
setup and motion control parameters are defined in software and are
managed on a high speed serial network. Manual adjustments, jumpers
and switches are eliminated.
- Flexibility & Scalability:
Use of industry standards provides you choices on selection of machine
I/O, PLCs, operator interfaces and factory network connectivity. Plus,
an ORION® system easily and cost-effectively expands up to 32 axes
without sacrificing servo performance.
- Distributed, real-time control:
ORION® utilizes a multi-processor architecture featuring Intel
architecture main processors and DSP-based axis control for servicing
the real-time needs of the servo system.
- Low Cost: The digital interface
replaces bulkier traditional drive interfaces --- dramatically
reducing wiring costs and providing installation simplicity.
ServoWire is all-digital.
The ServoWire Drive Network provides a
high-speed (200 Mbps), real-time, serial communications link between an
ORION® controller and up to 32 axes. Each ServoWire Axis Module
interfaces up to eight servomotors and/or pacer encoders.
ServoWire replaces the standard plus/minus
10 volts analog drive interface with a new all-digital interface. This
high response, digital control network supports servos, pacer encoders,
high speed sensors, I/O and programmable limit switches … offering
performance, flexibility & ease of use.
No more digital-to-analog conversions at
the controller, and no more analog-to-digital conversions at the
servodrive. When most controllers are powered by DSPs, and all the modern
servodrives are also DSP-based, it’s obvious that digital communications
between them makes sense. But until now, high cost and lack-of-speed have
kept most servo installations mired in analog transmission of servodrive
commands, and using phase-quadrature position feedback.
Digital communications allow all drive
parameters in a ServoWire system to be defined in software ... not by
potentiometers. At startup, setup parameters are delivered automatically
by the controller if required --- reading them from the system PC Card ---
a fact that greatly simplifies installation of a replacement drive in the
field.
ServoWire (top diagram above)
uses IEEE-1394 to create a potent architecture for multi-axis motion
control and synchronization. The system uses an IEEE-1394 memory mapped
model where all drive setup and motion control parameters are defined as
software variables and communicated in real-time.
Position and velocity loops (bottom diagram
above) are closed in the ServoWire Axis Module by transmitting digital
torque control and reading position feedback over the ServoWire network.
Up to 8 simultaneous torque commands are transmitted to the drives
digitally as 16-bit variables, eliminating the cost and limitations of
traditional D-to-A converters and analog torque signals.
Advantages of ORION®/ServoWire
Architecture
- Networked Servodrives: Servodrive
network communications implemented using open standard IEEE-1394
(FireWire) communications technology eliminates traditional +10
volt analog drive interface.
- Performance: Serial bus operates at 200
Mbps. Servo loop updates based on number of drives on network (2kHz
for 8 axes; 4kHz for 4 axes) as well as software features enabled.
IEEE-1394 guarantees real-time network determinism & provides
bandwidth for communication transfers.
- Ease of Use: IEEE-1394 provides true
Plug N Play. All motion control & drive parameters are
software-driven. No physical settings or off-line computer setup
required---simplifying field replacement of drives.
- Multi-processor architecture: Main Intel
architecture processor processes MotionBASIC® and is interfaced to
digital signal processor (DSP) on the ServoWire Axis Module via a
shared memory interface. The DSP handles the real-time servicing of
the servo system.
- Flexibility and scalability: ORION®
architecture and use of PC technology provides wide range of options
when specifying machine I/O, operator interface and factory network
connectivity.
- Industry-standard factory networking:
Use of standard PC hardware provides cost effective physical layer.
Industry-standard factory network protocols --- especially A-B
Ethernet and Modbus TCP --- provide connectivity to major PLC and HMI
suppliers such as Wonderware, Intellution, U.S. Data and CI
Technologies.
- Remote Connectivity: The combination of
TCP/IP, Ethernet and Windows networking provide a low cost method to
implement remote communications for development, maintenance and
reporting.
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