Industrial Engineer · phase 15 of 16 · noun
Reference / Feedback Word
Network data values used to send a speed or torque command and return actual operating feedback.
The Explain card
- Plain English
- The reference word is the speed or torque command the PLC sends over the network, and the feedback word is the actual value the drive returns. Both are scaled numbers rather than hertz or rpm.
- Example
- A drive's reference is scaled so that 16384 means 100 percent of maximum frequency. The PLC writes 8192 for half speed and reads back about 8192 once the drive gets there.
- Why it matters
- The scaling differs by brand and by profile, and a reference sent in hertz to a drive expecting a percentage runs the motor at the wrong speed with no fault. Check the scaling parameter and test at a safe low value first.
- Hook
- The setpoint and the answer, as numbers the profile understands.
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 writes the Reference Word over PROFINET while the technician monitors the Feedback Word in the drive telegram.
How it is built
- re- prefix back
- fer root carry or bear
- -ence suffix action, state, or result
Where it came from
- Origin
- Latin referre, meaning carry back or report, through English refer plus -ence
- Entered the language
- 1580s
- What changed
- It moved from the act of referring to a cited source, then to a standard, point, or value used for comparison.
How it is spelled
- Pattern
- It keeps the noun-forming ending -ence found in words related to verbs ending in -er.
- Pattern
- The letter sequence -ference also appears in several related abstract nouns.
- Breaks the pattern
- The middle e is retained in spelling but is often reduced or omitted in pronunciation.
Spelled like
- preference
- inference
- deference
- conference
Broken into chunks
-
refer
- referral
- referee
-
ference
- preference
- inference
- deference
What it sits beside
Same subject
- setpoint
- Control Word
- Status Word
- drive telegram
- process variable
Same shape
- preference
- inference
- deference
- conference
Drive telegram words
- Reference Word
- Feedback Word
- Control Word
- Status Word
Words ending in -ference
- reference
- preference
- inference
- deference
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.
