PLCopen seeks comments on TC3 TF PLC benchmarking standard

PLCopen Task Force is seeking comments on its recently proposed TC3 TF technical specification, which has been released to the community for comments until June 30, 2006. The organization is seeking feedback form a broader community about the specification’s usability for their environments before developing the applicable test software. The published version is 0.4, and is combined with a feedback form.

Though a benchmark is a reproducible, portable test to measure the performance of a given system in comparison to other systems, the task force reports there are no defined benchmarks for PLC systems. The only common measurement for PLC performance is the execution speed of 1,000 Boolean operations. This number isn’t a good benchmark because users can’t derive PLC performance in a typical application from it. Consequently, it’s not comparable between systems because the test conditions lack definition.  

The group adds there are two main objectives when using a benchmark: to estimate the performance of the PLC in your own application; and to compare the performance of the PLC with other PLCs, and find out the specific strength and weakness of a given system.

PLC open’s paper defines two different sets of benchmarks to meet the objectives described above. The first set of benchmarks defines five different types of applications, which are typical for the usage of a PLC. Most applications belong either to one of these types or consist of a mixture of them. The second set of benchmarks measures each language feature of the IEC 61131-3 separately. The goal of this test is to exclude effects of other features to the most possible extent.  

The released document is available free-of-charge at PLCopen’s website under “TC3–Certification/Task Force Benchmarking.”