Customer Solutions

Testing Plastic Piping Integrity

Author(s):

Ted White, E-JAZ Test and Measurement, Inc.

Industry:

Industrial Controls/ Devices/ Systems

Product:

Compact FieldPoint, FieldPoint, LabVIEW, LabVIEW Real-Time

The Challenge:

Creating an automated system to simultaneously control 16 independent test stations to test the structural integrity of plastic piping components.

The Solution:

Using a National Instruments FieldPoint real-time hardware platform and LabVIEW software platform to implement a system that reliably controls and monitors sixteen 16 electric water valves.

Automated system based on NI LabVIEW and NI FieldPoint products simultaneously controls 16 independent test stations.

Testing the Structural Integrity of Plastic
To assure proper structural integrity of plastic pressurized piping component manufacture, we must pressure test samples of each batch of plastic. The test calls for the components to be submerged in a tank of water heated to 80˚ C, then, and for the components to be pressurized with water. The test must maintain pressure for a specified period of time, typically 170 hours. Pressures rangeare anywhere from 150 to 350 PSI. A pump and pressure vessel, which maintains a pressure of approximately 400 PSI, feeds water to the system. Each station has a needle valve to limit the water flow, a digitally controlled ball valve, and a pressure transducer. We manually set the needle valve to limit the flow, and pulse the ball valve on and off to build and maintain the pressure.

The system is divided into two main components – an embedded component and a host component. The embedded component runs on a FieldPoint real-time embedded controller, and the host component runs on a Windows-based machine.

Short Learning Curve with Simple, Powerful User Interface
It was extremely important to the customer that the system be easy to operate. They did not want their operators, who were previously performing these tests manually, to have a long learning curve to get up to speed on using the new system.

When the system started, the main interface displayed to the operator. From this interface, the operator configured, started, stopped, monitored tests, and generated reports. The system allowed basic test parameters such as test time and data acquisition rate to be saved for later recall from file, which meant the operator could concentrate on the samples at hand and not have to remember the details of the industry-standard tests. The operator only needed to enter parameters specific to the sample under test; the system calculated other test parameters.

The main interface displayed summary information about all test stations in the system. To display additional information about a single station, the operator could press the “details” button to display the details screen. This screen opened as an additional window so that the operator could still see the main interface. On the details screen, a graph displayed all data collected for the current test and test parameters.

The operator could generate a report from either the main interface or the details screen. Reports saved as HTML files to allow for portability and ease of viewing using any Internet browser.

We ran the tests on the embedded FieldPoint controller. Once started, the system ran without the host application running. Under normal operating conditions, the host and the embedded controllers would be connected via an Ethernet cable. The two communicated using transmission control protocol. During a test, data transferred from the embedded system to the host, as programmed by the operator. Data was not normally logged on the embedded system. However, in the event that communication between the two systems was interrupted, data logged on the embedded system. When communication between the two systems resumed, the embedded system transferred all data to the host, and normal data logging on the host resumed. Sufficient storage capacity on the embedded controller stored a complete test on all stations at normal logging rate under standard test durations. Due to test length, it was imperative that the system continued to run in the event of a communication problem.

The embedded controller acquired data from all stations every second to allow the system to adequately control the pressure on each station and store data at the required interval.

Automated System Increases Test Integrity
Manually performing the pressure testing was a time-consuming task and, due to the human factor, data from the test was not collected as often as was desired. Automating the system freed technicians to do other work as well as increased the test integrity. A single operator could now set up and monitor all tests in a fraction of the time that wasrequired to do so manually. By choosing National Instruments products as the base of our system, we reduced development time and required a minimal amount of additional components.

For more information, contact:
E-JAZ Test and Measurement Inc.
11 Holland Drive, Unit 7
Bolton, Ontario L7E 1G7
Phone: (905) 857-4551
Fax: (905) 857-6753