Methods and apparatus for conducting in-service testing of pneumatic signal amplifiers

An apparatus for conducting in-service testing of a pneumatic signal amplifier, the apparatus comprising:

• a valve controller operatively coupled to and in fluid communication with the pneumatic signal amplifier, the pneumatic signal amplifier being operatively coupled to and in fluid communication with an actuator, the actuator being operatively coupled to a valve to move the valve in response to pressurized control fluid received at the actuator from the pneumatic signal amplifier, the pneumatic signal amplifier including a first control fluid inlet configured to receive pressurized control fluid from the valve controller, a second control fluid inlet configured to receive pressurized control fluid from a control fluid source, a control fluid outlet configured to supply pressurized control fluid from the pneumatic signal amplifier to the actuator, and a control fluid exhaust configured to vent excess pressurized control fluid from the pneumatic signal amplifier to an atmosphere, the valve controller including a first pressure sensor and a second pressure sensor, the valve controller further including a processor configured to:
• supply pressurized control fluid to the first control fluid inlet of the pneumatic signal amplifier in response to a test initiation signal;
• determine a first pressure value corresponding to an inlet pressure of the pressurized control fluid at the first control fluid inlet of the pneumatic signal amplifier as measured via the first pressure sensor of the valve controller;
• determine a second pressure value corresponding to an outlet pressure of the pressurized control fluid at the control fluid outlet of the pneumatic signal amplifier as measured via the second pressure sensor of the valve controller;
• determine a ratio value between the first and second pressure values;
• determine whether the ratio value satisfies a threshold;
• and
• in response to determining that the ratio value satisfies the threshold, generate a notification indicating that the pneumatic signal amplifier is functional.

A tangible machine readable storage medium comprising instructions that, when executed, cause a processor of a valve controller configured to conduct in-service testing of a pneumatic signal amplifier to at least:

• supply pressurized control fluid from the valve controller to a first control fluid inlet of the pneumatic signal amplifier in response to a test initiation signal, the pneumatic signal amplifier being operatively coupled to and in fluid communication with the valve controller, the pneumatic signal amplifier also being operatively coupled to and in fluid communication with an actuator, the actuator being operatively coupled to a valve to move the valve in response to pressurized control fluid received at the actuator from the pneumatic signal amplifier, the pneumatic signal amplifier further including a second control fluid inlet configured to receive pressurized control fluid from a control fluid source, a control fluid outlet configured to supply pressurized control fluid from the pneumatic signal amplifier to the actuator, and a control fluid exhaust configured to vent excess pressurized control fluid from the pneumatic signal amplifier to an atmosphere, the valve controller including a first pressure sensor and a second pressure sensor;
• determine a first pressure value corresponding to an inlet pressure of the pressurized control fluid at the first control fluid inlet of the pneumatic signal amplifier as measured via the first pressure sensor of the valve controller;
• determine a second pressure value corresponding to an outlet pressure of the pressurized control fluid at the control fluid outlet of the pneumatic signal amplifier as measured via the second pressure sensor of the valve controller;
• determine a ratio value between the first and second pressure values;
• determine whether the ratio value satisfies a threshold;
• and
• in response to determining that the ratio value satisfies the threshold, generate a notification indicating that the pneumatic signal amplifier is functional.