The first FireWire, or IEEE 1394- based motion control systems were introduced more than seven years ago to take advantage of the high-speed data network designed for computer and consumer applications. Since that time, a number of companies including, Ormec, Nyquist, Aerotech Inc., and others have developed motor drive communications systems using the IEEE-1394 physical layer. FireWire-based I/O has been introduced by Nyquist and Wago, and many companies provide FireWire-based vision systems.
So it would seem that almost all of the component pieces are in place to implement FireWire solutions.
One of the key driving forces beyond achieving broader acceptance is the 1394 automation group. Consisting of several European companies, it was established so that automation devices from different manufacturers could communicate with each other using the IEEE 1394 network standard. Earlier this year, participants presented the initial results of a cooperative effort between the 1394automation organization and CAN In Automation (CiA) users group at the Hanover Fair 2004. The goal is to define a smooth migration from accepted industrial CANopen devices to the industrial user of FireWire products. With this effort, both the data formats and communication services will be compatible. With available products, an active organization with key supplier, and university research members, FireWire appears to be poised for industrial acceptance.
Stalled on Takeoff?
Opinions are mixed over the popularity of FireWire and its potential for rapid adoption in motion control applications. "There is no indication now that FireWire is taking off for motion control," says Sal Spada, director of research for ARC Advisory Group, which researches on the motion control market.
"We do see some applications where engineers are trying to integrate motion and I/O together," Spada says. "If you're going to be a power and motor player today, you have to be willing to support almost any interface out in the market-whether it's Sercos, FireWire, Ethernet, or some of the newer Ethernet solutions coming out like SynqNet." Spada is not convinced that FireWire is making significant inroads in motion control except in niche areas.
But others disagree. Unlike many older technologies where control is implemented with plus or minus 10V digital to analog conversion, FireWire industrial controls are relatively new. Robert Novotnak, Aerotech's Division Manager, says the use of high-speed FireWire is the key to a distributed architecture that minimizes bottlenecks in computing power and creates flexibility in the end points. With that flexibility, the system can control brushless, brush, or stepper motors, interface to third-party drives, and support different drive packaging on each axis. Aerotech's customers report improved performance and also a reduction in wiring and interconnectivity issues.
"Based on the number of other companies supplying FireWire solutions and customer acceptance of this type of solution, it would appear that it is gaining acceptance in industry," Novotnak says. "Since the FireWire solution is still relatively new for control systems, the key item that will increase the rate of acceptance is successful integration of this architecture."
Aerotech recently introduced the Nservo, a FireWire-based digital controller module that provides a link to its A3200 digital automation platform. "The Nservo has been used mostly to upgrade existing machines or interface to third-party drives as a cost-saving measure," Novotnak says.
|Firewire for Linear Motion: Nyquist Industrial Control and OTB Engineering developed a linear transport system for vacuum applications based on linear motor technology that uses the deterministic behaviour and the direct master-to-master communication of IEEE 1394. The system shares sensor data between adjacent coils and uses specific control algorithms for each coil that requires synchronization between the set-point generators of different coils.|
Ormec is another pioneer in FireWire motion control. Ormec's Vice President of Marketing and Sales, Dave Carr, says that instead of treating FireWire as a technology that requires adoption Ormec is "taking advantage of what FireWire technology allows."
Carr feels that FireWire is in a better position today than it was a year ago in terms of acceptance by engineers. "We have many OEM customers who are looking at the long-term advantages of FireWire as a motion network," he notes.
If customers require high-speed motion control, I/O, and vision, the true advantages and simplification of FireWire are apparent. However, even if only two of the three functions are required, say, motion control and vision or motion control and I/O, the use of a single network can simplify implementation and potentially provide a lower-cost solution.
According to Carr, many companies are interested in taking advantage of the availability of all three. For example, medical and semiconductors are two specific markets that are interested in these combined capabilities since they both push the envelop for performance. Packaging and material handling are also considering FireWire.
Changing technology invariably involves changing software and that is where much of the anxiety arises in transitioning to FireWire. If the change in technology also means changing suppliers, the decision-making process and programming effort can be even more difficult. However, Carr contends that when engineers are convinced that a motion control system provides them the solution for their unique problems, the transition is one they are willing to make.
With its ServoWire and Motion Control Logic (SMLC), Ormec provides a low-cost, high-speed network for interfacing the drives to keep the controls cost down. The SMLC addresses the weakness of the PLC datalink, so many of the problems that users have with PLC-based motion controls are solved with the FireWire-based approach.
|Isochronous Data Frame: With IEEE-1394's isochronous data transfer capability, time dependent readings are scheduled by the bus to be delivered once every 125 usec by the data frame.|
|Flexible Connection: Ormec's ServoWire and Motion Control Logic (SMLC) can control several servo motors using the IEEE 1394 interface and can use the same interface or other protocols including Ethernet or Profibus DP to connect the I/O.|
For engineers looking for a high-speed motion control network-very capable at very good price points-today's FireWire looks like it could provide that capability. What's more, IEEE 1394 B, FireWire 2, is already defined providing a road map for scalable improvements up to 3.2 Gbit/sec. FireWire 2 requires optical fiber cable but can deliver data up to 100m.
Carr is convinced that 1394 B is going to drive FireWire technology to further acceptance. "We have had many customers tell us that anything they do with FireWire now, they are going to do with 1394 B," he asserts. With 1394 B, FireWire could have the one-two punch to get the industry to move in its direction.
|Multiple Servo Loops: Ormec's ServoWire uses IEEE-1394 to create a multi-axis motion control and synchronization architecture. Servo loops for up to 8 axes are managed in real-time with torque commands transmitted digitally as 16-bit variables.|
|Going Digital: A FireWire-based high-speed control bus replaces several dozen wires and connections with a single cable, reducing costs, while increasing reliability and simplifying installation. The digital network eliminates digital to analog conversion at the control and at the servo drive.|
Reach contributing editor Randy Frank at [email protected] .
|Aerotech: http://rbi.ims.ca/3860-571||Ormec: http://rbi.ims.ca/3860-572||1394 automation group: http://rbi.ims.ca/3860-573|