Brewer toasts wireless networking success
28 June 2010
Wireless technology has enabled faster network connections to be achieved following a control system upgrade at the Plzensky Prazdroj ‘Pilsner Urquell’ brewery in the Czech Republic
During a recent upgrade at the Plzensky Prazdroj (PP) brewery in the Czech Republic, Siemens solution partner, FMA Process Engineering advised an upgrade from the kegging line’s existing Siemens S5 control platform to a Siemens S7 system with ProfiNet wireless communication.
The kegging line uses three automated carousels that pre-wash, wash and fill kegs 24 hours a day. The line handles one thousand kegs an hour so it was imperative that its new control system could keep pace with this level of production. The carousels had been in operation for over 15 years, controlled by S5-95U PLCs, each communicating to a S5 115U over a Sinec-L2 network.
The original system used slips rings to bridge the Sinec-L2 to the carousels, and while this worked adequately, limited network throughput meant that it was not suitable for high speed data transmissions as part of a new control system.
To bring both the performance and reliability of the wireless communication network on site up to benchmark standards, FMA installed a system using ProfiNet and an Industrial Wireless Local Area Network (IWLAN). In addition, the existing Siemens S5 software was converted and re-engineered to provide the functionality required to accommodate the upgraded system, and HMIs throughout the site have since been upgraded to to provide enhanced operator control.
A total of 14 existing S5 115U and S5-95U PLCs were combined into one CPU416-3 PN/DP processor. All associated I/O was rewired to ProfiNet variants of both ET200M and ET200S remote I/O.
On both the pre-washer and washer carousels, the existing 12 S5-95U PLC control was combined into a single ET200S CPU and the remaining stations converted to ProfiNet ET200S remote I/O devices.
On the filler carousel, control of the existing 12 S5-95U PLCs was distributed across two ET200S CPUs and the remaining stations converted to ProfiNet ET200S remote I/O devices.
Wireless survey
Fundamental to the success of any wireless deployment is a wireless survey. As industrial plants typically contain a lot of heavy machinery, metal and concrete, all of which pose potential obstacles, it is vital that these issues are identified and a system configured to address them.
Wireless network specialist, Daconi worked with Siemens at FMA’s request, to conduct a wireless survey at the plant. The wireless survey was performed using WiFi survey tools and imported plan drawings of the plant area. The radio coverage of each access point was measured and the optimum location to install the access points and the best antenna and antenna location for the wireless clients was established. The system was then tested in situ to verify wireless performance.
The IWLAN system was configured to work in the 5GHz band since the wireless survey showed some sources of wireless interference in the 2.4GHz band, which is more prone to interference because of its widespread use.
The final scheme at PP’s brewery includes Siemens Scalance IWLAN access points that transmit ProfiNet wirelessly at a data rate of 54 Mb/s between Scalance W786-1Pro access points and Scalance W784-1 gateway clients, providing seamless connection to the ProfiNet network, controllers and I/O modules.
Each rotating carousel was fitted with a panel-mounted Scalance W784-1 operating in wireless distribution system mode using an externally mounted omni-directional dome antenna for all-round radio coverage. The wireless survey showed that this antenna performed better than a standard dipole type. The W784-1 units communicate with two girder-mounted IP65-rated Scalance W786-1Pro access points utilising internal omni-directional antennas.
The upgrade far exceeded PP’s expectations. Apart from significant improvements to the efficiency of the operators have benefited from reduced downtime thanks to an enhanced alarm function that enables faults to be located and rectified more quickly. There is also quicker resumption of power in the event of a power outage which has improved productivity.
The reduction in the numbers of PLCs at the plant has meant much less reliance on inter-PLC communications – a former source of problems that were difficult to diagnose and remedy. The service technicians have found the S7 PLC code easier to follow and this, too, has had a positive impact on downtime reduction.
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