Industrial Engineer · phase 12 of 16
Speed Reference
Commanded speed or frequency value received from the keypad, analog input, preset, PID, or network.
The Explain card
- Plain English
- The speed reference is the value that tells the drive how fast to run. It can come from a potentiometer, an analog input, a preset, a network word, the keypad, or the drive's own PID loop.
- Example
- A PLC writes 45 hertz into the drive's reference word over EtherNet/IP. The drive ramps to 45 and holds there until the word changes.
- Why it matters
- The reference source is a parameter, and a drive listening to its keypad while the PLC writes to the network runs at whatever the keypad last said. When a motor runs at the wrong speed, ask where the reference is coming from before you ask why.
- Hook
- How fast, from a source the drive was told to trust.
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.
