Industrial Engineer · phase 12 of 16 · noun

Forward / Reverse

Direction command that selects the sign of motor rotation subject to configuration and interlocks.

The Explain card

Plain English: Forward and reverse choose the direction of rotation. On a drive it is a command, since swapping two motor leads is no longer needed to reverse a motor.
Example: A reversing conveyor gets two inputs, run forward and run reverse. The drive ramps down through zero and back up the other way, with no contactors and no waiting for the motor to stop.
Why it matters: Which direction is forward is a convention set at commissioning, and a drive replaced with the leads landed differently runs the machine backwards on the first start. Reverse can also be locked out in a parameter, which is the right thing for a pump or a fan.
Hook: Direction is now a bit, and bits can be wrong.

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

In a sentence

The PLC energizes the Forward input after the drive-ready contact closes and the reverse command is confirmed off.

How it is built

Where it came from

Origin: Old English foreweard, formed from fore, meaning in front, and -weard, meaning directed toward
Entered the language: c. 9th century
What changed: The spatial sense of toward the front broadened into uses for movement, progress, transmission, and designated machine operation.

How it is spelled

Pattern: The suffix -ward attaches directly to a direction or position word.
Pattern: The spelling retains the internal sequence r-w even when the second syllable is reduced in speech.

Spelled like

Broken into chunks

What it sits beside

Same subject

Same shape

drive direction commands

directional words ending in -ward

Phase 12: VFD Commands, References, and Stopping

Starting, referencing and stopping, including the several very different things a drive can mean by the word stop.