Industrial Engineer · phase 6 of 16 · noun
Discrepancy Time
Maximum allowed time difference between the expected state changes of paired safety channels.
The Explain card
- Plain English
- Discrepancy time is how long two channels of a safety input are allowed to disagree before the controller calls it a fault. It exists because two real contacts never change at exactly the same instant.
- Example
- A door switch's channels are set to a 50 millisecond discrepancy. One contact opens, the other follows 8 milliseconds later, and the input is treated as a clean open. If the second one never follows, the input faults.
- Why it matters
- Too short and healthy switches fault on every slow actuation, too long and a real wiring failure hides for that long. The value is a judgment about the device, and the vendor's number is the place to start.
- Hook
- How long the two witnesses may argue.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
During commissioning, the technician sets the discrepancy time for the dual-channel guard switch before testing its channel-delay fault response.
Why these words
- discrepancy Latin discrepantia, disagreement identifies a mismatch between related signals
- time Old English tima, a period or season makes the phrase name a timing parameter
Where it came from
- Origin
- English technical compound formed from discrepancy and time
- Entered the language
- 20th century
- What changed
- Discrepancy moved from general disagreement to measurable signal mismatch, while time became a configurable control parameter.
How it is spelled
- Pattern
- discrepancy keeps the noun ending -ancy
- Pattern
- time uses silent final e to mark the long i sound
Spelled like
- vacancy
- constancy
- timer
- timing
Broken into chunks
-
dis
- disagree
- disconnect
-
crep
- crepitate
- decrepit
-
ancy
- vacancy
- constancy
-
time
- timer
- timing
What it sits beside
Same subject
- dual-channel input
- safety relay
- guard switch
- cross-circuit detection
Same shape
- response time
- delay time
- scan time
safety timing parameters
- discrepancy time
- response time
- restart delay
Where it sits in the deck
Phase 6: PLC Operating Modes, Safety, and Diagnostics
Run, program and fault: what a controller does when something goes wrong, and the safety functions that decide how much that costs.
