Testing Technology: Automatic Final Inspection / VTS Test Bench

• The human error factor has been eliminated by the automated final inspection.
• Incorrectly delivered valve islands to customers have dropped to 0 (ZERO-DEFECT FAILURE = 0).
• The employee only needs to insert the test specimen, make contact, and start the test, then has about 2 minutes for other tasks, so is not bound the whole time.

For a customer in the pneumatic solutions sector, we designed a test bench for the final testing of valve terminals (VTS = valve support system) and integrated it into the existing production line.

Through an internet configurator, the valve island can be customized. Due to a variety of options such as:

• Number, type (5/2 way valve, 5/3 way valve, 2x 3/2 way valve, etc.) and sequence of valves
• Number and type of I/O modules (digital/analog, input/output)
• Type of fieldbus communication (12 different types)
• Number and position of pressure separations

the variances of valve islands approach infinity. Nevertheless, the final product should be automatically tested before being shipped to the customer to ensure functionality and correct assembly.

We accepted the challenge and developed a test bench that can control the valve terminal to be tested via an IPC with fieldbus cards.

When the valve terminal is ordered via the internet configurator, it creates a file containing the TARGET configuration. This configuration file is read by the test stand at the time of testing. The test stand then generates the necessary individual tests and compares TARGET with ACTUAL configuration. For example, each valve is switched in a specific sequence to determine that the correct valve is installed in the correct position.

In addition, a leakage check of the valve terminal is performed for various conditions (switched valves/unswitched valves) to control the tightness. After successful testing, the test stand initiates the printing of the product label for the tested unit and sets the fieldbus module to the delivery state.