Industrial Engineer · phase 12 of 16
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.
Where it sits in the deck
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.
