Nirmal Industrial Controls Interview Questions and Answers

SS 304 and SS 316 are both austenitic stainless steels, but with different compositions and properties.

• SS 304 contains 18% chromium and 8% nickel, while SS 316 contains 16% chromium, 10% nickel, and 2% molybdenum.

• SS 316 is more corrosion-resistant than SS 304, especially in chloride environments.

• SS 316 is more expensive than SS 304.

• SS 304 is commonly used in food processing equipment, while SS 316 is used in marine and chemical processing applications.

Dimensional standards for flanges and pipe fittings

• Flanges and fittings are manufactured according to various dimensional standards such as ASME, DIN, JIS, etc.

• These standards specify the dimensions, tolerances, and materials for flanges and fittings.

• For example, ASME B16.5 is a widely used standard for flanges in the United States.

• It is important to select the correct standard for the application to ensure proper fit and function.

• The dimensions of flanges and fittings can al...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 measurement range, while 20 mA represents the maximum val...read more

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 include globe valves, butterfly valves, and ball valves.

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, while RS232 is typically half-duplex.

• RS485 uses balanced t...read more