PST Partial Stroke Test 

For some important control valves (including emergency shut-off valves) that keep running in a certain state for a long time, due to the long-term "dormancy" state, they may not be able to respond to the operating instructions of the SIS (safety instrumented system) in emergency situations, resulting in the failure of the SIS system. Brings risks and hazards to safety. PST Partial Stroke Testing is a very good safety measure to set up periodic partial stroke action tests to ensure proper operation of the control valve.