Validation of calibration software ? as required by ISO 17025, for instance ? is a topic that people don?t prefer to talk about. digital pressure gauge there is uncertainty about the following: Which software actually must be validated? If so, who should look after it? Which requirements must be satisfied by validation? How would you do it efficiently and how could it be documented? The following blog post explains the background and gives a recommendation for implementation in five steps.
In a calibration laboratory, software can be used, among other activities, from supporting the evaluation process, up to fully automated calibration. Whatever the degree of automation of the program, validation always identifies the entire processes into which the program is integrated. Behind validation, therefore, is the fundamental question of whether the process of calibration fulfills its purpose and whether it achieves all its intended goals, in other words, does it provide the required functionality with sufficient accuracy?
To be able to do validation tests now, you should be aware of two basics of software testing:
Full testing is not possible.
Testing is always dependent on the environment.
The former states that the test of most possible inputs and configurations of an application cannot be performed as a result of large number of possible combinations. According to the application, the user should always decide which functionality, which configurations and quality features should be prioritised and that are not relevant for him.
Which decision is made, often depends on the second point ? the operating environment of the software. With respect to the application, practically, there are always different requirements and priorities of software use. Additionally, there are customer-specific adjustments to the program, such as concerning the contents of the certificate. But also the average person conditions in the laboratory environment, with an array of instruments, generate variance. The wide variety of requirement perspectives and the sheer, endless complexity of the program configurations within the customer-specific application areas therefore ensure it is impossible for a manufacturer to check for all the needs of a particular customer.
Correspondingly, considering the above points, the validation falls onto an individual themself. In order to make this process as efficient as possible, a procedure fitting the next five points is recommended:
The info for typical calibration configurations should be defined as ?test sets?.
At regular intervals, typically once a year, but at the very least after any software update, these test sets should be entered into the software.
The resulting certificates could be weighed against those from the previous version.
Regarding a first validation, a cross-check, e.g. via MS Excel, may take place.
The validation evidence ought to be documented and archived.
WIKA provides a PDF documentation of the calculations carried out in the software.
Note
For more info on our calibration software and calibration laboratories, go to the WIKA website.