Symbology in Process Control

Symbology in Process Control

• Electronic Signals are represented by a dashed line.
• Pneumatic Signals are represented by a line with perpendicular lines, resembling train tracks.
• Digital Signals are represented by a dash, circle, and dash.
• Current to Pneumatic Transducer is represented by a dashed line transitioning into a solid line with train tracks.
• Check Valve is depicted as a vertical line with a diagonal arrow pointing upwards within it.
• Orifice Plate is represented by three vertical lines, with the middle line being shorter.
• Block Valve is depicted as a bow tie with a T shape on top.
• Control Valve is represented as a bow tie with an umbrella shape on top.
• Motor Operated Valve is depicted as a bow tie with a rectangle containing an "M" in the center.
• Pump is represented with a suction line running through the middle and a discharge line at the top.
• Exchanger (tube side) is depicted with a line passing through a zigzag line signifying the tubes.
• Exchanger (shell side) is represented with a pointing arrow directed towards and out of the tubes but not passing through them.

Instrumentation and Control Abbreviations

• FIC stands for Flow Indicator Controller, responsible for measuring and controlling flow rates.
• TE stands for Temperature Element, a sensor used to detect and measure temperature changes.
• TAL stands for Temperature Alarm Low, an alarm that triggers when the temperature falls below a set threshold.
• PI stands for Pressure Indicator, used to display pressure measurements.
• LG stands for Level Gauge, an instrument used to measure the level of a liquid in a tank or vessel.
• d/p stands for Differential Pressure, the difference in pressure between two points.
• FCV stands for Flow Control Valve, a valve used to regulate the flow rate of a fluid.
• LALL stands for Level Alarm Low Low , an alarm that triggers when the level of a liquid falls below a very low threshold.