Each year, more than 250,000 Opel Astras roll off the production line at the Opel plant in Antwerp, Belgium, with every vehicle passing through the different production areas. For almost 10 years, car bodies have been finished in the paint shop. After such a long service life, an increasing rate of failures was being reported in the system, particularly among electromechanical units, which, in the worst-case scenario, can result in costly production failures.
The imminent increase in the total cost of ownership (TCO) and the fact that the programmable logic controller (PLC) had been discontinued by the manufacturer has led Opel, which is a 100 percent subsidiary of General Motors, to invest in the modernization of automation in this area. Opel chose a distributed automation concept from Phoenix Contact, which is headquartered in Blomberg, in East Westphalia, Germany, because of the well-established partnership between the two companies.
Ethernet onboard
The IBS RFC 430 ETH-IB control system from Phoenix Contact was chosen to control the conveying application, such as the supply of car bodies from the body shop and their transport within the paint shop. The control system has been integrated into the existing Ethernet network for the control room, without the need for additional controller boards. It also has an onboard INTERBUS controller board in the field. (See photo.)
Data access integration has been achieved by using an optimized OPC server that allows standardized access to the control and INTERBUS data. In addition, service personnel can view essential diagnostic data for the control system, INTERBUS system and Ethernet connection via a liquid crystal display (LCD) and a cursor keypad. Parameterization memory enables quick replacement, if required, without the need for time-consuming adjustments.
The control systems are programmed using Phoenix Contact’s PC WorX 3.0 software. This software meets the requirements of the International Electrotechnical Commission (IEC) 61131 standard for programming languages. In addition, PC WorX combines a programming environment, fieldbus configuration, diagnostics and an OPC server, which means the user does not have to switch between different software packages during start-up or when optimizing the system.
Integrating OPC and visualization
In order to enable all system-specific data, visualization and identification to be monitored from the control room, a switched Ethernet network is used. The installation of industrial switches close to the control system prevented large, extensive star structures from having to be deployed.
The INTERBUS OPC server from Phoenix Contact provides the connection to the visualization and/or management level. With this, INTERBUS process data and program variables are exchanged over Ethernet between the Phoenix Contact control systems and the OPC clients. A maximum of 16 control systems can be connected with an INTERBUS OPC server.
The control system provides the requested values of the OPC items in the Multi Port Memory (MPM). The INTERBUS OPC server reads and writes the INTERBUS input/output data that the OPC client can access. The OPC specifications for Data Access—DA 1.0a and DA 2.04—are supported. The configuration data file of the INTERBUS OPC server, which contains the information from the control system to be presented by the OPC server, is generated automatically from PC WorX.
To verify a successful communication connection, Phoenix Contact provides the diagnostics OPC client. With the OPC test client, the correct function of the INTERBUS OPC server and the availability of the OPC items can be tested.
Each conveying system section—Line 1 and Line 2—has two visualization computers that retrieve the data directly from the control system via OPC communication. A control system is assigned to each visualization computer. The computers on each line can view the other’s data, thus there are always two INTERBUS OPC servers to access one control system.
A data volume of approximately 1,000 tags is transmitted per line. This means the operator computer always has access to the entire process data, for example, to control the speed of a belt or the paint colors. GENESIS32 software from Iconics is used for visualization and supervisory control and data acquisition (SCADA).
Re-use of existing resources
It would have been impractical to replace all of the existing control cabinets and control devices, and new cabinets could only be used to a limited extent. Therefore, the existing equipment was only partially replaced in these areas.
Many functions have been replaced by the modular Inline I/O system. Some, such as motor management and power supply, have been moved from the control cabinet to the field. For example, the IBS IP 400 motor structure and frequency inverter with IP 54 protections is connected to the INTERBUS system. Varioface system cabling was used to connect to the 400 to 500 existing 120-volt relays, which resulted in about a 30 percent space savings.
One of the main advantages of the modernization is the improvement of maintenance. Maintenance personnel need to be able to find and remove errors quickly and precisely, in order to prevent future downtime and increase system availability. In addition to displaying the error location, DIAGNet software—a combination of DIAG+ diagnostic software and an installation service—simultaneously displays the links to circuit diagram pages, data sheets, and system diagrams to enable the error location to be found more quickly.
Maintenance personnel can access the necessary documents locally in their visualization systems, if required, and do not have to return to the support center. The DIAG+ basic software is installed via the ActiveX interface using drag-and-drop techniques. The costs associated with implementing error message texts in the visualization can be eliminated, as the software displays all error descriptions and remedies as required. Consequently, function blocks in the PLC are also no longer required.
The Phoenix Contact automation solution has enabled the clear and compact integration of the most important devices required by Opel Antwerp for system communication and control. The OPC server provides the necessary connectivity to the SCADA system. The standardized OPC interface enables fast engineering and commissioning, combined with flexible operation and easy configuration changes, if needed.
Further advantages include network transparency, simplified installation, the ruggedness of devices, a high level of diagnostics and improved maintenance in the paint shop, which has been achieved through the use of the AUTOMATIONWORX automation kit from Phoenix Contact.
For more information on solutions from Phoenix Contact, visit www.phoenixcontact.com.
