Testing of smart meters includes various tests and means of analysis. These include functional tests of common daily procedures. Functional tests can also be used for testing the data communication of the meter. However, the reason that the results of this type of testing only reveal half the truth is explained in this article.
The objective of a functional test is to ensure the proper execution of a functional procedure. For example, a predefined value is queried, the corresponding response is compared with the expected value and this is subsequently evaluated (correct or incorrect). If the returned value and the expected value diverge, the result is then “Failed”. If the result is negative, the meter can be sorted out. Meters that are found to be “good” can be deployed in customer installations.
Functional tests that have delivered positive results in the laboratory, however, only provide information about whether the meter under test will later be able to communicate properly in the field with other pieces of equipment. The reason is that a functional test evaluates the result, but not the manner in which the communication operates between the test system and the meter under test.
Consequently, meters under test are not evaluated based on their communication behaviour, but instead on the result they return.
So how can you ensure that meters under test, perhaps even from different manufacturers, can communicate with each other properly based on a common specification?
In our next issue, please read about how our STM6000 digital measuring system uses implemented communication analysis to help deal with this question and why only a combination of functional testing and communication analysis can provide optimal overall results.