Product details
Vendor: Supervisory and Control Engineering (SCE)
Product name and version: GE-Fanuc 90-30
Tel: (016) 982 3700
e-mail: [email protected]
URL: www.sce.co.za
General
Q: What industry (eg mining, food and beverage, automotive etc) is the PLC being applied in?
A: The PLCs are being applied in various warehousing applications in the steel manufacturing industry.
Q: Describe the application briefly giving a description of any existing control systems, any previous PLC system that was in place etc. If relevant describe the switchover from the previous system.
A: The PLCs are installed on overhead cranes as part of a warehouse management system tracking and controlling the movements of process stock handled with the overhead cranes. The purpose of the PLCs is to constantly monitor the positions of the crane hooks and interlock specific crane movements when needed. Constant interaction is needed between the host and PLCs.
The host runs a Delphi application with an Oracle database. All the movements of process stock are done according to schedules downloaded from the enterprise system (mainframe). The movement of a specific item is initiated by someone on the floor with a portable terminal to the host (RF connected device with built-in bar code scanner). Some movements can also be initiated by the crane driver himself on the HMI. The host then sends a command to the PLC. The command info is displayed on the HMI for the crane driver to act on. The PLC offers the crane driver a step-by-step generic process with which to carry out the command. Interlocking certain crane movements prevents potential collisions. These interlocks come into play when an attempt is made to move the incorrect item, or an illegal movement is attempted. When the movement of an item is completed, the enterprise system is updated.
Q: Who did the system installation/integration?
A: The complete project was done in-house. The only part that was done by an outside contractor, in this case the vendor of the PLCs - SCE, was the wiring of the PLC panels.
Q: Approximately how many man-hours did the installation/integration take?
A: Approximately 1000 man-hours.
Q: How is the after-sales support handled (eg remote-dial-up, e-mail, Internet access etc)?
A: Because it was an in-house project, support on the systems is done on site by in-house staff.
System architecture
Q: How many I/Os does the installation have? Analog? Digital? Maximum possible?
A: I/Os consist of a high-speed counter detecting encoder pulses, 8 digital inputs and 8 digital outputs.
Q: What impressed you most about the architecture? Open standards, wide range of drivers, the ability to upgrade, etc? Please elaborate.
A: The CPU 364 with built-in Ethernet port is being used, it is a fast, powerful and easy-to-use CPU. The ability to program a PLC with Versa-pro from the host PC is a great advantage.
Q: Does the PLC have a built-in user interface? Describe.
A: A Proface operator panel (now a GE product) is being used as a human-machine-interface which is a very powerful, easy to configure device and integrates very easily with the PLC.
Q: What sort of redundancy is built into the system?
A: No redundancy was built into the system.
Compatibility
Q: Do you run the PLC in conjunction with any third-party application software or hardware? Describe.
A: The Versa-pro software is being used to program the PLCs. It is also used to do support and fault finding on the PLCs from the host PC. For the communication between the host PC and the PLCs, the In-gear active-X component is being used.
Conclusion
Q: What was the predominant feature (or features) that made you decide to employ this PLC, rather than another (ie ease of use, support from the vendor, upgrade path, redundancy features etc)?
A: The main consideration was standardisation. Other factors in favour of the PLC are good support from the vendor and ease of use.
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