Woodfield Systems International Instrument Engineer Interview Questions and Answers

Control valves regulate the flow of fluid in a system by varying the size of the flow passage.

• Control valves are used to control the flow rate, pressure, temperature, or liquid level in a system.

• They operate by varying the size of the flow passage through the valve in response to a signal from a controller.

• Control valves can be operated manually, pneumatically, electrically, or hydraulically.

• Examples of control valves ...read more

RS485 is a differential serial communication standard for long-distance communication, while RS232 is a single-ended standard for short-distance communication.

• RS485 is differential, allowing for longer distances and better noise immunity.

• RS232 is single-ended, limiting distance and noise immunity.

• RS485 supports multi-drop communication, while RS232 is point-to-point.

• RS485 uses half-duplex or full-duplex communication, ...read more

4-20 mA signal is commonly used in industrial control systems due to its robustness and ability to transmit over long distances.

• 4-20 mA signal is less susceptible to noise and interference compared to voltage signals.

• It allows for longer transmission distances without significant signal degradation.

• It is easy to convert to a digital signal for processing by control systems.

• 4 mA represents the minimum value or 0% of the...read more