For PROFIBUS devices of different types and manufacturers to be able to perform different tasks in the automation process correctly, they must exchange information over the bus without errors. A prerequisite for this is a standard-compliant implementation of the communication protocols and application profiles by the device manufacturer. To ensure that this demand is met, PI established a quality-assurance procedure where certificates are granted for test-passing devices. Certification, assures users that PROFIBUS field devices from different manufacturers are capable of error-free operation when used together. For this purpose, the field devices are tested in practical applications in accredited independent test laboratories.
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The test procedure, which is the same for all test laboratories, has several steps:
- A GSD/EDD check ensures that the device description files comply with the specifications.
- During the hardware test, the electrical properties of the PROFIBUS interface on the test subject are tested for compliance with the specifications.
- The function test addresses the bus access protocol, transmission protocol and the functions of the test subject.
- The conformity test is the focal point of testing. It verifies that protocol implementation is in line with the standard. The test primarily covers the state machine, behavior in case of errors, addressability, diagnostic data, and mixed operation.
- During the interoperability test, the interplay between the test device and the PROFIBUS devices from other manufacturers is tested in a multi-vendor system.
- The profile test is carried out to determine whether the test devices work together smoothly during operation. The profile test is carried out for the PROFIdrive, PA device, and PROFIsafe profiles. The test determines whether the profile functions were implemented in accordance with the specifications.
Once a field device has passed all the tests, the manufacturer can request a certificate from PI. Each certified device includes a certification number as a reference. The certificate has a validity of 3 years and can be extended by a manufacturer declaration or after new testing. The addresses of the test laboratories can be obtained from the PI website.
