VSD/drive ignores the direction command
A drive runs but only one way — the reverse (or forward) command is ignored, even though the drive is running and the motor turns.
Safety first
Reversing under a drive can be sudden. Ensure the load and area are safe for reverse motion before testing. Isolate before touching control terminals.
Isolate, lock out / tag out, and prove dead before working unless a live test is specifically required, authorised, and carried out under proper supervision. Always follow local regulations, your site procedures, and the equipment manufacturer's documentation.
Full detail — causes, the why, and common mistakes.
Likely causes
Ranked from most to least likely.
- 1
Reverse disabled in drive parameters
Most likelyMany drives have a parameter to allow/block reverse; if reverse is disabled, the command is ignored.
- 2
Direction command not reaching the drive
#2The reverse digital input or network command isn't getting to the drive (wiring, wrong terminal, control source).
- 3
Wrong control source for direction
#3Direction is set to come from a source you're not using (keypad vs terminal vs network).
- 4
Single direction by configuration
Least likelyThe drive is configured for one direction only by design.
Reports are saved on this device to reflect what you actually find.
Testing sequence
Work through one test at a time. Expected reading and what each result means.
Check the drive's monitor for whether it's receiving the reverse command and from which source.
Reverse command shown as received from the expected source.
Drive sees the command — check the reverse-enable parameter.
Command not seen — check the input wiring/terminal and control source.
View all expected readings at once
Fault-finding flowchart
The same logic as a decision tree.
- 1start
Drive ignores direction
→ step 2 - 2decision
Does the drive show the reverse command as received?
Yes→ step 3No→ step 4 - 3decision
Is reverse operation enabled in parameters?
Yes→ step 5No→ step 6 - 4result
Command not seen — check input wiring/terminal and control source.
- 5result
Enabled and seen but ignored — re-check command path/source.
- 6result
Reverse disabled — enable it if the application allows.
Common mistakes apprentices make
- Assuming a wiring fault when reverse is simply disabled in parameters.
- Commanding reverse from a source the drive isn't set to use.
- Not checking the drive's own monitor for the received command.
- Enabling reverse on an application that shouldn't run backwards.
When to stop & escalate
If reverse is disabled for a process reason, confirm it's appropriate to enable before changing it. Persistent issues with the command path may need the drive documentation.
If you're past your competence, authorisation, or the safe limits of the job — stop and hand it on. There's no fault worth getting hurt over.
Related faults
VSD powered up but won't start the motor
The drive is energised and the display is alive, but it won't run the motor. No fault may be shown — it just sits in 'ready' or 'stopped' and ignores the start command.
Motor goes one way but won't go the other (e.g. down but not up)
A reversing drive works in one direction only. One command (say, down) runs fine; the other (up) does nothing, or just hums/trips. Common on hoists, doors, and conveyors.
PLC output LED is on but the device doesn't work
The PLC output indicator says the output is energised, but the connected device (valve, contactor, lamp, motor starter) does nothing. The program thinks everything is fine.