CIP Networks Testing: Interoperability, performance, conformance, recommended practice
The idea that devices can conform to a specification and may not interoperate can confound end-users, system integrators, and device manufacturers alike. ODVA and its members have been working to close that gap with conformance, interoperability and performance tests. See photos.
|Workshops and "PlugFest" events from ODVA help ensure interoperability among CIP-enabled devices.|
Howey-in-the-Hills, FL – The idea that devices can conform to a specification and may not interoperate can confound end-users, system integrators, and device manufacturers alike. ODVA and its members have been working to close that gap with conformance, interoperability and performance tests, along with recommended practices for Common Industrial Protocol (CIP) networks from ODVA .
ODVA’s device conformance tests provide a declaration of conformity (DOC) to devices deemed to conform to the specification by passing protocol, physical layer, and interoperability tests. ODVA also offers device manufacturers (vendors) other ways to work toward better interoperability.
The EtherNet/IP implementor workshop series runs in North America and in Europe. Each series ends with a multi-vendor interoperability event called “PlugFest” in each region. Kevin Knake of HMS Industrial Networks is the chair of the North American workshop series. Viktor Schiffer of Rockwell Automation is the chair for the European series. While HMS and Rockwell are among ODVA members, non-members may participate in the events.
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Knake says that knowledge gained during workshops and PlugFests helps clear ambiguity in the EtherNet/IP specification, helping vendors achieve interoperability more quickly. Workshops and PlugFests organizers expect to develop a troubleshooting guide along with recommendations for web diagnostics and security, network behaviors, IP address assignments, and testing for multiport devices.
This work by ODVA and its members “aims to accelerate adoption of EtherNet/IP and promote interoperability of devices from multiple vendors to improve user experiences,” Knake says, noting that, at present, devices can conform with specifications and not interoperate.
For those making EtherNet/IP-compliant devices, PlugFest participation gets them closer to pleasing customers. An average of 52% of products comply with the PlugFest test suite, Knake says; participants use lessons learned to improve devices before products are introduced. Identifying compliance issues earlier in the product development cycle costs as little as one-tenth of what it would have cost to fix after the product is introduced.
ODVA also has launched EtherNet/IP performance testing. These tests, run at ODVA’s test labs, aim to provide users with data on product network performance. That information helps match product performance to application requirements. Tests measure network performance, including type and number of network connections supported and the time elapsed between frames of network traffic. Vendors then can build on the interoperability testing offered at PlugFest, providing greater understanding about what devices can do for which applications.
The route to ODVA device interoperability for CIP networks
Efforts toward interoperability include:
Conformance : Standard device conformance testing provides an ODVA “Declaration of Conformity” (or “DOC”) for those devices that pass that test suite, showing compliance with the specification.
Interoperability and performance tests : Devices that go through PlugFest or ODVA performance tests successfully can have their DOC updated to indicate this. Within PlugFest testing is a limited performance test, which devices now are required to pass to pass the PlugFest testing. A comprehensive performance test is also run by ODVA at its labs, and this performance test includes a report.
Recommended practices : These are developed between specifications updates, passing along new knowledge to vendors. As the name suggests, these are not required, Knake says, but desirable, since they increase the probability of interoperability.
Next PlugFest is May 5-7 : ODVA provides details on EtherNet/IP North American PlugFest #11 , located in Ann Arbor, MI. Registration deadline is April 28, 2009; non-members may attend.
– Mark T. Hoske, editor in chief
Control Engineering News Desk
Register here .