|PROJECT:||Perth Arena Retractable Travelling Roof|
|DESCRIPTION:||Vector Lifting is a Western Australian based engineering firm specialising in the design and manufacture of mechanical lifting systems and jib cranes. Vector Lifting has been at the forefront of design and fabrication of railway maintenance equipment and jib cranes for over 20 years.|
|REQUIREMENTS:||KAPP Engineering was required to provide a control system to control of the opening and closing functions of the two roof segments (i.e. East and West Roof Segments) at Perth Arena. Each roof segment was required to have local status indication and controls as well as remote status indication and controls at the Event Control Centre (ECC).
The opening and closing operation of each roof segment was to be monitored closely in such a way that it maintained zero skew during the entire movement. The skew of the roof segments was determined by measuring the position of the two sides of the roof (i.e. Restrained and Free sides). The control system was required to vary the speed of the Free side of the roof segment in order to maintain zero skew while the Restrained side travels at a constant speed.
Position measurement on each side of the roof segment was achieved utilising two sensors, the Stahltronic Linear Encoder being the primary position measurement and a Rotary Encoder being the secondary position measurement. These encoders were to be continuously monitored to determine their accuracy throughout the length of roof travel.
|SOLUTION:||The control system was broken down into the following areas, each consisting of a Koyo DL405 PLC and a C-More HMI (8” TFT Colour HMI on each side of the roof segments and 15” TFT Colour HMI on the ECC). All communications was via an Ethernet Network.
KAPP Engineering designed and developed a flexible and user-friendly control system, including overview style graphic screens which allowed the operator to view the status of both roof segments at a glance. Operation of the roof was as simple as pressing the Open/Close button with the desired target position/destination. All system settings and alarms are accessed and viewed on the ECC to provide assistance to the operator for troubleshooting and maintenance purposes. Intuitive system settings and maintenance mode controls ensure that the system is highly flexible and simple to maintain and troubleshoot.
Each roof segments skew correction during an opening / closing operation is automatically controlled by the Restrained and Free Side PLCsutilising PID Closed Loop control based on feedback from the position measurement system (i.e. Stahltronic and Rotary Encoders). A backup system is also in place to ensure that the roof operation is stopped when the maximum skew distance is reached.