The Challenge:

Developing a PC based system, which can replace the outdated Contactor Logic System and a Temperature controller that controls FRP Vessel curing water Bath system. The system is to provide improved control of the system, reduce the chance of malfunction/defects and increase the production.

The Solution:

Building a system that automates FRP Vessel curing water Bath system, which is reliable, flexible and can do both monitoring and control of the system. This system is accessible on the network, uses FieldPointä RT Ethernet module, distributed I/O modules and LabVIEW Real-Time.

Introduction:

A system was developed that automates Fiber Reinforced Plastic (FRP) Vessel curing system. Movement of two hoists and temperature of a water bath working at 100 degrees are controlled. The system has 64 Digital inputs, 24 Relay outputs, 8 Thermocouple inputs and One RT Ethernet module. Each Hoist should stop at the Bath position and 3-mould positions depending on the requirement. The Temperature and Time at which the mould went inside the bath can be accessed on the network.

National Instruments’ FieldPoint RT Ethernet module, various input/output modules and LabVIEW Real Time software are used in the solution

Application:

The FRP Vessel curing water Bath system that was running with Contactor Logic System was automated using National Instruments’ Field Point RT Ethernet Module, various input/output modules and LabVIEW Real Time software.

The application consists two hoists and one water bath working at 100 deg. Temperature. The movement of the hoist and temperature of water bath are controlled by the system. The system has 64 inputs, 24 outputs, and 8 thermocouple inputs. Each Hoist should stop at the Bath position and 3 mould positions depending on the requirement. All the 64 Inputs are from Limit switches. Outputs are to Hoist Motors, Pump Motors, Solenoid coils and Indication Lamps. There are six Mould stations. Each Hoist travels from three Mould Stations to the Water Bath carrying one mould at a time. The Mould with Hoist remains in water bath for a specified set time and comes back to the original station. The main objective of this project was to increase the production by 20% after complete automation of the system, Figure 1 shows the old setup using contactor logic system and figure 2 shows the Hoist setup.

System Design:

Considering the disadvantages of traditional Contactor Logic System in continuous logging of data and writing complicated control logic, we opted for LabVIEW to write the entire application because this program effectively overcomes the shortcomings of traditional Contactor Logic System.

The application runs on a FP-2000 under LabVIEW RT. Using Lab VIEW RT we can run LabVIEW code embedded on an FP-2000-based distributed system. For the I/O hardware, we chose a Field Point distributed I/O modules. The Control System for the 2 Hoist’s has 64 digital I/O points for which four FP-DI-301 and FP-RLY-420 were connected, and for the eight thermocouples FP-TC-120 was connected. Using the FP-2000 Controller and LabVIEW Real-Time has the following advantages; A dedicated execution system separate from the PC for added safety Execution on a true real-time platform with shorter and guaranteed response times and a much smaller Hardware package. The PC is needed only for visualization of data and transfer of data from FP2000 to the host.

There is a visual display only on the Host PC, of temperature and Time at which mould is inside the bath. Temperature will be logged as and when it is connected to the server using Ethernet. In the Host computer Display of a bath with hoists, movement of hoists, and position of hoists, temperature of the bath, decrement times while hoist is in the bath position are also displayed.

Software Implementation:

The software is divided into several distinct parts – the first is the basic control of the four axes movements (e.g. move to a certain position, UP and Down movement etc.), plus the control of all the auxiliary systems. This layer is always active in automatic as well as manual mode. We can control this system from the PC, and from the main control panel.

The second part of the software is the automatic error recovery functions. In our case, this is particularly important because abnormal conditions can occur. For example, the crane can get stuck; the wheels can slip on the rails; the crane cannot lift up because the load is too heavy, and so on. The system software was designed to take such conditions into account and also have the ability to resolve them automatically (e.g. jiggle the crane forward and backward to make it move again etc.)

The third part is the visualization functions, which form an integrated part of the application this is implemented in the Host. While the first part (the basic control) could be implemented with a PLC, it would be very difficult to implement the other parts with a PLC system. Many of today’s automation problems are not limited to simple control tasks, but rather complex processes that must run fully automatically. Modern systems of this type are also expected to imitate the behavior of a human operator in abnormal conditions and react “intelligently” in order to keep the necessary human intervention to an absolute minimum. The data transmission from the FP-2000 to host system is implemented using TCP/IP and the data can be accessed anywhere on the network.

Conclusion:

With LabVIEW and FieldPoint, we were able to seamlessly integrate all aspects of an automation solution, such as control functions, process automation, error recovery, visualization, database integration and statistics. The LabVIEW platform is very well suited for automation applications. This platform can replace all aspects of traditional automation and with an onboard, dedicated processor, of FP-2000 the ability to execute the critical code on a separate hardware target under a real-time system greatly enhances the performance of the system. When we started we were planning to achieve at least 20% increase in production after automation, but we where able to achieve 40% increase in production at the end of our project.