PRESS RELEASE
Tools are the key to successful Profibus implementation
David Medlyn and Dr Tim Cooper outside the new brewhouse
Coopers Brewery - Australia's third largest brewer, and largest family-owned brewery - was founded
by Thomas Cooper in South Australia in 1862. When Coopers Brewery relocated from Leabrook to Regency
Park in 2001, the company took the opportunity to expand its capacity by commissioning an entirely
new brew house. International brew house designers Briggs of Burton proposed linking all measuring
points with a Profibus communications system, based on its outstanding success in other brew houses
worldwide. Recognising that Profibus technology would effectively ‘future-proof' the company's new
plant, MD Dr Tim Cooper agreed and Coopers thus gained Australia's first Profibus PA-networked brew
house.
Even today, the Coopers brew house remains one of Australia's most modern brew houses. Its
state-of-the-art Profibus technology includes both Profibus DP (utilised in the control room to link
the PLCs and SCADA), Profibus PA (utilised extensively throughout the plant for the measurement and
control of level, temperature, flow, pressure and valves) and ASi bus (for the digital I/O). Also
installed were power meters, temperature, pressure and level transmitters and flow control valves.
Successful commercial brewing depends on the accurate management of a highly complex series of
processes. Precise, integrated process data on density, flow, level, pressure, pH and temperature are
crucial for effective process control.
Temperature, pressure and level devices neatly cabled to Profibus
According to David Medlyn, Senior Process Control Engineer at Coopers Brewery, since the introduction
of Profibus, his process managers are now obtaining more accurate and immediate feedback on every
measurement parameter and measuring point at all process stages. Better process control has also
increased the efficiency of subprocesses within the brew house - such as the collection of spent grain
and CIP processes.
Medlyn and his team did have to work through a few issues as part of their learning curve - most
notably in the area of communications. Medlyn explains: “Communications can be lost if the last node
in a segment loses power. This interferes with the termination resistance of the segment and can pull
down the entire network.” Australia's only accredited Profibus International Competence Centre (PICC),
established by Tyco Flow Control Pacific, states that a termination resistor must be placed at the ends
of each segment to prevent this problem from occurring. “If using a powered termination resistor it does
not take an address on a segment, but does represent a device and a maximum of 32 devices can be linked
in a segment,” explains Grant Weyman, Tyco's Technical Services Manager - Controls, at the Competence
Centre. “Slave addresses must be allocated carefully and recorded by the installer,” he adds.
If a device is set to an address that has already been assigned to another device, it will cause
conflict errors. “Although best avoided in the first place, double addressing can be easily picked up
by an analysis tool,” notes Weyman. Planning and installing networks have indeed come a long way with
the introduction of advanced analysis tools that make it easy to locate faults and get detailed network
information.
Weyman is also a strong advocate of proper documentation. “When installing large networks one must
be careful to ensure adequate documentation is produced and checked off I may be stating the obvious
but it is easy to overlook some installation and commissioning checks,” he notes.
Brew houses are typically harsh environments whose high temperatures, aggressive processes and
caustic cleaning materials can be hazardous for workers and machinery and damaging to cabling. By
radically reducing the amount of cabling needed within the Coopers brew house and enabling process
instruments to be added quickly and easily into the network, Profibus radically reduces the potential
for cable damage and the time, costs and dangers associated with maintenance. Furthermore, Profibus
enables ‘plug and play' commissioning. The programmer simply obtains the relevant GSD file, adds the
new node onto the segment and with an update to the control logic it's ready to go.
One of the key advantages of Profibus is its flexibility - minimal additional cabling is required
when extra nodes are installed. Medlyn is particularly impressed by the robust performance of Profibus
PA, and the simplicity and convenience of its troubleshooting capabilities. When an instrument is
damaged, the Profibus network does not fail and the source of the problem is instantly identifiable
from the control room. Process managers can also proactively prevent instrument failure by remotely
detecting incipient problems and pinpointing where attention is required. This reduces process down
time and batch wastage and minimises resources spent on maintenance.
Having experienced the benefits of using Profibus PA and seen the resultant increase in the quality
of its products, Coopers is continuing to introduce Profibus PA throughout the remainder of the plant
as it upgrades and expands to meet growing market demand for its products. “We find that the 4-20 mA
loops in our plant require more calibration work and are not as reliable or as accurate compared with
those on the Profibus network,” concludes Medlyn.
The Coopers team has deployed ProfiTrace as the predictive maintenance tool across the network.
This powerful analysis tool enables technicians to check and troubleshoot the complete Profibus network
and thus plays a significant role in plant asset management at Coopers Brewery.
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