Industrial Engineer · phase 15 of 16 · noun
Control Word / Status Word
Bit-mapped network command and feedback data used to control and monitor a drive.
The Explain card
- Plain English
- The control word is a sixteen bit value the PLC sends to the drive with bits for run, stop, reset, direction and so on. The status word is the value the drive sends back with bits for running, faulted, at speed and ready.
- Example
- The PLC sets bit 0 in the control word and the drive starts. The drive's status word bit 2 comes on to say it is running, and the PLC watches that rather than assuming.
- Why it matters
- The bit layout is specific to the profile, so a drive expecting one profile and a PLC sending another produces a drive that ignores every command. Confirm the profile, then map every bit by name in the PLC rather than by number.
- Hook
- Sixteen switches out, sixteen lights back.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
During commissioning, the PLC sets the enable bit in the Control Word, then verifies the ready bit in the Status Word.
Why these words
- control Anglo-French contrerolle, a counter-register used for checking identifies the commanding member of the paired terms
- word Old English word, speech or utterance uses the computing sense of a fixed group of bits
Where it came from
- Origin
- English technical compound formed from control and the computing sense of word
- Entered the language
- 1940s
- What changed
- Word shifted from spoken language to a fixed-size digital unit, while control narrowed from general regulation to machine-command terminology.
How it is spelled
- Pattern
- Control doubles its final l before vowel-initial suffixes, as in controlled and controlling.
- Pattern
- Word keeps the wor spelling used for the same r-colored vowel pattern in work and worm.
- Breaks the pattern
- In word, the letters or do not have the vowel heard in cord.
Spelled like
- patrolled
- compelled
- work
- worm
Broken into chunks
-
control
- controller
- controlling
-
word
- keyword
- word-length
What it sits beside
Same subject
- Status Word
- command register
- fieldbus
- drive enable
- fault reset
Same shape
- command word
- data word
- machine word
- status word
drive communication words
- Control Word
- Status Word
bit-mapped fields
- enable bit
- ready bit
- fault-reset bit
Where it sits in the deck
Phase 15: VFD Parameters and Communications
The parameter set itself, and the network words a controller uses to read and write it while the machine is running.
