Partial stroke tests for shutdown valves

A method for executing partial-stroke tests of valves, the method comprising:

• generating a setpoint signal to stroke a valve during a partial-stroke test, including:
• determining a first target for the setpoint signal based at least on a travel displacement threshold, the travel displacement threshold corresponding to a desired extent of travel of the valve during the partial-stroke test, wherein the first target corresponds to a larger extent of valve travel than the travel displacement threshold,
• ramping the setpoint signal from an initial value to the first target, during a first time interval,
• subsequently to the first time interval, maintaining the setpoint signal at the first target during a second time interval,
• determining a second target for the setpoint signal based at least on the initial value, and
• during a third time interval subsequent to the second interval, ramping the setpoint signal from the first target to the second target in a direction opposite to the ramping of the setpoint signal during the first time interval;
• applying the setpoint signal to the valve;
• and
• determining whether the valve passes the partial-stroke test using a response to the setpoint signal.