Industrial Engineer · phase 1 of 16 · noun

Backplane

Internal bus that distributes power and data between modules in a PLC rack or chassis.

The Explain card

Plain English
The backplane is the circuit board inside the rack that every module plugs into. It carries power to each slot and moves data between the CPU and the cards.
Example
An input card sees a switch close. That bit travels across the backplane to the CPU without any wire you ever landed.
Why it matters
Backplane traffic has a bandwidth limit, and a rack full of fast analog cards can crowd it. Backplane faults also look like module faults, so a card that fails in one slot and works in another is telling you about the rack.
Hook
The wiring you never see is the wiring that carries everything.

Word knowledge

How the word is built, where it came from, and what it sits beside in memory.

In a sentence

When a 1756-IB16 discrete input card in slot 3 reports a closed limit switch, the ControlLogix CPU in slot 0 reads that bit across the backplane.

How it is built
  • back- prefix rear; at the far side
  • plane root flat surface; a sheet
Where it came from
Origin
English compound of Old English baec, rear, and Latin planum, a flat surface, formed in computing on the model of ground plane
Entered the language
1960s
What changed
Back and plane were independent words for centuries. Electronics used plane for a conducting sheet, then set back in front of it for the connector sheet at the rear of a card cage. Catalogs dropped the hyphen, and PLC racks kept the closed form.
How it is spelled
Pattern
Closed compounds of back plus a noun are written as one word
Pattern
After a short vowel, English writes /k/ as ck, so back never uses kk
Pattern
The silent e in plane holds the long a; dropping it would make plan
Breaks the pattern
Older manuals still write back-plane with a hyphen; the open form back plane is a different phrase in optics

Spelled like

  • backbone
  • backlash
  • airplane
  • hydroplane
Broken into chunks
  • back
    • backbone
    • backlash
    • backhand
  • plane
    • airplane
    • hydroplane
    • monoplane
  • ack
    • pack
    • stack
    • track
What it sits beside

Same subject

Same shape

  • backbone
  • backlash
  • airplane
  • hydroplane

PLC rack parts

Closed back- compounds

  • backbone
  • backlash
  • backhand

Where it sits in the deck

Phase 1: PLC Controller Hardware

The box itself, from processor and rack to the modules that plug into it, because nothing else in the deck lands until you know what a PLC physically is.

Neighbours in this phase