Why do verification approaches in automation rarely use HIL-test?

Nowadays, model-driven formal verification approaches are much researched for testing industrial control applications. However, these approaches can´t check the system for bus errors, faulty hardware configurations and compatibility problems efficient. For sufficient testing, Hardware-in-the-Loop (HIL) test should be used. But the HIL-test is rarely used in the field of automation because of missing experience with it and great costs by using vendor-dependent solutions. This paper will discusses the current problems of HIL-tests for verifying the control applications and presents a promising vendor-independent approach for its implementation.