New Australian Synchrotron uses safety PLCs

By Frank Schrever Pilz Australia

The newest and biggest piece of scientific equipment in Australia is the Australian Synchrotron, located in Melbourne, which shoots electrons around its 216 meter (708.7 foot) circumference in just 720.5 nanoseconds.

Synchrotrons are highly efficient in use, gathering data for research ranging from medical, environmental, advanced materials, and engineering to minerals, exploration, and even forensics. An experiment that would normally take one year to do in a lab using conventional techniques can be done using a large synchrotron facility in an estimated few hours or days.

“Synchrotron light technology is currently central to about 80 percent of drug discovery and development, with the certainty that it will soon move to 100 percent,” Australian Nobel Prize winner Dr. Peter Doherty said. “The net effect is to reduce drug design times from several years to a few weeks.”

Extensive safety protection is needed to guard scientists and workers from any possible exposure to synchrotron light – the electromagnetic radiation emitted when charged particles, usually electrons or positrons, moving at velocities close to the speed of light, are forced to change direction under the action of a magnetic field. Synchrotron light can be generated across the range of the electromagnetic spectrum, from infrared to X rays, but at intensity hundreds of thousands of times higher than that from conventional X-ray tubes.

“Just understanding the hazards was a major issue initially,” said Sergio Costantin, radiation safety specialist for the Australian Synchrotron, pictured in Figure 1, courtesy of Steve Morton/Australian Synchrotron. “If you’re outside the synchrotron’s rings, there’s absolutely no danger because it all happens inside concrete tunnels with walls up to a meter thick. But, you simply can’t be inside when the synchrotron starts.”

Figure 1

Despite this, the synchrotron’s massive magnets and their cooling circuits require constant TLC, making regular human access to the synchrotron’s tunnels essential, explains Richard Farnsworth, Australian Synchrotron lead control system engineer.

Before turning on the electron gun, a thorough check of all the tunnels must be completed. Two people start at one end of the tunnel and walk down, pressing safety or search buttons along the way until they complete the search and leave the machine. Each button must be pressed in the right order and within the right time frame. If one is missed or the search takes too long, the process must start all over again. “We can’t have people sneaking in behind the search,” Farnsworth said. “It had to be so safe that even Homer Simpson could operate the synchrotron safely.”

Rated at Category 4 under AS4024.1 or SIL3 of AS61508, a redundant safety system is mandatory for the synchrotron, but its integrator, Sage Automation, faced a fundamental design challenge. “Since the design of the synchrotron equipment was not complete at the time the contract was awarded, the safety system had to have the flexibility to adapt to new Input/Output (I/O) requirements,” said Sage’s Robert Craig. “Remote I/O modules using a Safetybus communications network provide this flexibility.”

Safeguards based on safety PLCs
The Australian Synchrotron safety system incorporates two Pilz Programmable Safety Systems (PSS 3000) or safety PLCs, along with a Pilz PMIvisu touch screen machine interface. It incorporates 68 emergency stop buttons, keyed interlocks, Fortress gates, video cameras, and even an intercom – all used to control personnel access into and out of the six controlled areas, and to provide immediate isolation of energized equipment in an emergency. All the safety and operations data is fed into an archive system so that in the unlikely event of an incident, investigators could effectively retrace the steps of synchrotron staff.

Each PSS 3000 safety PLC monitors a discrete area of the plant. PSS 1 monitors the electron gun and the booster ring while PSS 2 monitors the storage ring. A Pilz Machine Interface (PMI) in the control room (see Figure 2) interacts with both PSSs via Ethernet cable. This third-generation PMI, a PMIvisu, is configured and operated using PMI-PRO graphics software and enables detailed diagnostics to be made on the PSSs.

Figure 2

Farnsworth said the safety system is ideal for the synchrotron. “Old-fashioned relay-based systems have proven less reliable, increasing down time and giving no end of trouble. We have a system that is safe, flexible, cost-effective, and leading-edge rather than bleeding-edge. And our physicists are very happy with the safety system so far because it’s something that works extremely well with minimum training required.”

Inside the PMI
A single Pilz Machine Interface (PMI) controls the PSS 3000 safety PLCs that monitor the Australian Synchrotron’s electron gun and storage ring, respectively. This recently released third-generation PMI improves upon earlier versions in speed, memory, and other significant ways that make it easier and quicker to integrate into machinery or process equipment.

With a 400 MHz XScale PXA255 processor, the speed of the third-generation PMI is double that of the second-generation, and SDRAM memory is now upgradeable from 64 MB to 128 MB if required – in addition to the standard 32 MB of flash memory. The operating system is also Windows CE.NET version 4.2 instead of CE 3.0, and an RJ45 10/100 Mbps fast Ethernet connection is standard (with a second Ethernet interface offered as an option).

More USB connections are provided (two or four hosts and one slave, as opposed to one host USB port on the previous generation), and all models feature a variety of other ports, such as a PCMCIA slot (for two Type II or one Type III card), a PC/104 expansion slot, a PS/2 input, COM1 (RS-232), COM2 (RS-232/422/485 switchable), an audio line out, and an optional parallel port.

Another development is the move from using external fieldbus adapters to pre-installed internal modules. This speeds integration and saves valuable cabinet space.

Designed for diverse, rough environments, the PMI is ventilation-free, and the front panel is protected against dust and sprayed water and conforms to IP65; the back conforms to IP20. All units are designed for operating temperatures of 0 to 50 °C and a relative humidity of up to 90 percent.

The PMI is available in five screen sizes: 5.7 inch, 6.5 inch, 10.4 inch, 12.0 inch, and 15.0 inch. The 5.7-inch model uses LCD (CSTN) technology; the others use LCD (TFT) technology.

Open, or integrated with software
There are two versions of the PMI:

1. The PMIopen comes with just the operating system installed and is aimed at users who do not wish to be restricted in their choice of graphics software. It will run software compatible with Windows CE.NET 4.0. Pilz has already successfully tested three Scada packages: zenOn from Copa-Data, Web Studio from InduSoft, and Movicon from Progea.
2. The PMIvisu includes the Pilz PMI-PRO runtime software. The extensive, wide-ranging functions of the PMI-PRO software simplify the configuration and commissioning of plant and machinery. With PMIvisu running PMI-PRO, it is possible to control even large-scale projects with different PLCs simultaneously. When used specifically with PSS programmable safety systems, PMIvisu enables the use of diagnostics via an error evaluation package, thereby allowing rapid troubleshooting and fault recovery while a plant or machine is in operation. Plain text messages and graphical overview screens offer user-friendly diagnostics.

PMIopen and PMIvisu operator and diagnostic terminals are designed and built to ensure simple integration into existing networks. The units have all the common interfaces and enable several controllers to be connected simultaneously. A remote access tool is supplied with each unit.

Features of the PMI-PRO graphics software
For project engineers and plant operators, PMI-PRO works as a multifunctional cross-sector solution. Using ready-made buttons and aids, the project engineer can provide each customer with tailor-made graphics within a very short timescale.

For plant operators, machinery is made simple, fast, and convenient to operate by the availability of messages that are clearly legible and well presented, plus a wide range of software functions. For example, visual messages can be supported by audible signals, getting messages noticed more quickly while the plant is running.

One of PMI-PRO’s features is online language switching. Series users can make projects multilingual from the start, and thereby save costs during installation. When projects are created in a multilingual format, it is simple to switch the operator language even during operation. The foreign-language texts can be checked, looking for parameters such as text length, during configuration. UNICODE is supported. The program also allows password protection, object libraries, and offline simulation.

PMI-PRO graphics software enables PMIvisu graphics touch-screen terminals to be connected to a wide range of PLCs, even simultaneously. A selection of drivers for common PLCs is available for this purpose. For example, PMIvisu can be connected to Modbus, Siemens S5 and S7, and Allen Bradley units.

A fully networkable software version that runs on the PC is available. The step up to a full SCADA system can be achieved without loss of data, because all the configured data is transferred. 

Frank Schrever is managing director at Pilz Australia. He has a BAS (honors) from the University of Melbourne and has more than 28 years of experience in the instrumentation and automation markets. Frank sits on the Australian standards committee for Safety of Machinery, Plant and Equipment and is a board member of the Certified Functional Safety Expert Governance board, which oversees the formal certification of safety professionals.

To learn more, contact Pilz at:

Pilz Automation Safety L.P.
7150 Commerce Blvd.
Canton, MI 48187
Tel: 734-354-0272
Fax: 734-354-3355
E-mail: Michelle Tedrick, mtedrick@pilzusa.com
Website: www.pilz.com