Block 2 - PLC Ladder Logic - SAMA Drawings Self Assessment Flashcards
What is the main advantage of two-element drum level control?
It offers tighter control over drum level compared to single-element systems
What do enclosure symbols in SAMA diagrams represent?
Different elements or functions of the control system
What does the symbol [f(x)] represent in some SAMA diagrams?
An inherently non-linear valve characteristic or a positioner with a characterizer function
What does a PID controller stand for?
Proportional-Integral-Derivative
Which symbol represents a flow transmitter in a SAMA diagram?
FT-53
What is a SAMA drawing?
A functional control diagram for the power industry
Which organization developed the symbols and conventions used in SAMA diagrams?
Scientific Apparatus Makers Association (SAMA)
What is the primary purpose of SAMA diagrams?
To describe and document control strategies for industrial and utility boiler applications
In a PID controller, what does the setpoint (SP) value represent?
The desired value the process variable should reach
Which control strategy is ideally suited for boiler plants with multiple boilers and feedwater pumps?
Three-element drum level control
What are digital inputs in PLC ladder logic?
Binary signals that are either “on” or “off”
What is the purpose of analog outputs in PLC ladder logic?
To control parameters such as temperature, pressure, flow rate, and voltage
What does ladder logic resemble?
A ladder with vertical rails and horizontal rungs
What do PID loops in PLCs do?
Generate an output to apply corrective effort to a process
What is a PLC?
A programmable logic controller used to automate industrial processes
