Why Is It Called a Function Block Diagram?

The Founder's Explanation (Teach Exactly This Way)

"Beyond this we can explain why Function Block Diagram. Function = work. Block = diagram. That function work will be performed in that block diagram. So it is called FBD — Functional Block Diagram."

Teaching the Concept

Three words. Each with meaning. Understand each from home — the whole concept becomes obvious.

FUNCTION = the specific job to be done

Sunday afternoon. Parents assign tasks:

"Ravi — go buy vegetables"
"Priya — cook rice"
"Grandma — fold the clothes"

Each person has one specific job. That job = Function.

In BMS: "Read the temperature from sensor" = one function. "Compare with setpoint" = one function. "Open the valve accordingly" = one function.

BLOCK = the dedicated space where that function runs

Each family member works in their dedicated space:

Priya cooks → Kitchen (her block)
Ravi shops  → Vegetable shop (his block)
Grandma     → Living room (her block)

The space dedicated to one function = Block.

In BMS: each function has its own box drawn on screen — a rectangle enclosing that one job.

DIAGRAM = the drawing connecting all the blocks

The household works because spaces connect in the right order — Ravi brings vegetables to Priya in kitchen, Priya sends cooked food to dining table. The drawing that shows these connections = Diagram.

In BMS: lines connect the blocks, showing how output of one becomes input of the next.

FUNCTION BLOCK DIAGRAM =
A drawing of connected boxes where each box does one specific job
and results flow from box to box until the final output is produced.