Customer Solutions

Increasing Production with LabVIEW-Based Automation of FRP Vessel Curing Water Bath System

Author(s):

G. Giridhar, Captronic Systems

Industry:

Water/Wastewater

Product:

Compact FieldPoint, Distributed I/O, FieldPoint, LabVIEW, LabVIEW Real-Time

The Challenge:

Developing a PC-based system to replace an outdated contactor logic system (CLS) and temperature controller that manages the FRP vessel curing water bath system.

The Solution:

Using a FieldPoint Real-Time Ethernet module, distributed I/O modules, and LabVIEW Real-Time to build a networked system that reliably monitors and automates the FRP vessel curing water bath system while improving the control system, reducing the chance of malfunction and defects, and increasing protection.

Increasing Productivity with LabVIEW Real-Time
Previously, the FRP vessel curing water bath system ran a CLS, but we upgraded it using the National Instruments FieldPoint Real-Time Ethernet Module, various input/output modules, and LabVIEW Real-Time software.

The application consists of two hoists and one water bath working at 100 degrees. The system, which controls movement of the hoists and temperature of water bath, has 64 inputs from limit switches, 24 outputs to operate hoist motors, pump motors, solenoid coils, indication lamps, and eight thermocouple inputs to monitor temperature. Depending on the requirements, each hoist should stop at the bath position and up to three of the six mould positions. Each hoist travels from three mould stations to the water bath carrying one mould at a time. The mould and hoist remain in the water bath for a set time and then returns to its original station.

Installing FieldPoint Distributed Control
Considering the disadvantages of writing complicated control logic with the traditional Contactor Logic System, we opted to use LabVIEW to write the entire application. The embedded application runs on a FP-2000 controller running LabVIEW Real-Time. For the I/O hardware, we chose FieldPoint distributed I/O modules. As mentioned previously, the control system for the two hoists has 64 digital I/O points for which we connected four FP-DI-301 and FP-RLY-420 modules along with eight FP-TC-120 thermocouples. Using the FP-2000 controller and LabVIEW Real-Time, we developed a dedicated execution system separate from the PC for added safety. Our upgraded system executed on a true real-time platform, providing shorter and guaranteed response times and a much smaller hardware package.

We use the PC only for visualization of data and transfer of data from FP-2000 to the host. We visually display on the host PC both the temperature of the bath and the time the mould spends in the bath. We also display position and movement of the hoists and decrement times while a hoist is in the bath position. We log temperature data using a server that connects to the host PC via Ethernet. The host PC receives data transmissions from the FP-2000 using TCP/IP, and because of this, we can access the data anywhere on the network.

Dividing Software Tasks into Parts
We divided the software into several distinct parts - one part provides basic control of the four axes movements of the hoists plus the control of all the auxiliary systems. We keep this first layer, which we can control from the PC or from the main control panel, always active in both automatic as well as manual mode.
Our second software layer automatically resolves system errors. In our case, we find this particularly important because abnormal conditions can occur. For example, the crane can become stuck; the wheels can slip on the rails; the crane may not lift up because of a heavy load, and so on. We designed the system software to resolve these error conditions on its own.

The final part of our software implementation contains visualization functions, which closely integrate with the other two parts of the system. While we could have implemented the first part (the basic control of the hoists) with a PLC, we would have had great difficulty implementing the final two parts with a PLC system. Many of today’s automation problems do more than simply control tasks, but rather manage complex processes that must run automatically. We expect modern systems of this type to imitate the behavior of a human operator in abnormal conditions and react "intelligently" to keep necessary human intervention to an absolute minimum.

Surpassing Expectations
With LabVIEW and FieldPoint, we seamlessly integrated all aspects of an automation solution, such as control functions, process automation, error recovery, visualization, database integration, and statistics. The LabVIEW platform was well suited for automation applications and replaced all aspects of traditional automation. Also, with an onboard dedicated processor using FP-2000, we could execute the critical code on a separate hardware target under a real-time system, which greatly enhances the performance of the system. When we started we planned to achieve at least 20 percent increase in production after automation, but we actually achieved 40 percent increase in production at the end of our project.

For more information, contact:

G. Giridhar

Captronic Systems

#19, Alif Arcade Koramangala, 1st Block, 7th Main Road

Bangalore - 560034

Karnataka, India

Tel: 91-080-5535046, 552961

Fax: 91-080-5504054

E-Mail: capsys@vsnl.com

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