| User-Defined Fault 2 | Fault 2 Signal given by the users through multi-functional terminals or PLC Programming Function |
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ERR22 – User-Defined Fault 2
What this means
ERR22 indicates that the VFD has received a second user-defined fault signal.
Like ERR21, this fault is not generated by the VFD itself.
It is triggered by an external input, multi-function terminal, or PLC logic that has been configured by the user or system integrator.
Why This Happens
VFDs support multiple user-defined fault channels so integrators can implement:
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Multiple safety conditions
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Interlocks
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PLC-driven fault logic
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Custom shutdown behaviors
When the condition assigned to User-Defined Fault 2 becomes active, the VFD reports ERR22 and stops operation.
Most Common Causes We See
1. External input assigned to User-Defined Fault 2 (most common)
Examples:
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Secondary safety switch
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Door or enclosure interlock
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PLC output
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CNC controller fault signal
If this signal changes state, ERR22 is triggered.
2. PLC or controller logic asserting a fault
If PLC logic:
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Detects a programmed condition
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Sends a fault signal intentionally
The VFD will fault even though nothing is physically wrong.
3. Wiring issue on the assigned input
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Loose terminal
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Intermittent connection
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Incorrect NO vs NC wiring
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Broken conductor
This can cause ERR22 to appear intermittently or unexpectedly.
4. Unintentional configuration
ERR22 may occur if:
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User-defined fault logic was enabled unintentionally
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Parameters were copied from another machine
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Configuration was not reset after testing
What to Check First
Step 1: Identify the assigned User-Defined Fault 2 input
Check VFD parameters to determine:
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Which terminal or PLC function triggers ERR22
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What signal condition causes the fault
Step 2: Verify external device state
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Confirm the external device is in its normal, non-fault state
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Check signal continuity or voltage if applicable
Step 3: Inspect wiring
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Power down the VFD
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Verify terminal screws are tight
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Check for damaged or pinched wiring
Step 4: Disable User-Defined Fault 2 if not needed
If you are not intentionally using a second user-defined fault:
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Remove the terminal assignment
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Disable the PLC logic
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Reset the VFD
This will usually clear ERR22 immediately.
How to Clear ERR22
Once the external fault condition is removed:
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Reset the VFD
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Ensure the signal is stable
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Resume normal operation
The VFD will not restart until the fault input is cleared.
What ERR22 Is Not
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Not a spindle motor fault
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Not a VFD hardware failure
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Not a cutting load issue
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Not EMI related
ERR22 is always caused by external or user-configured logic.
Summary
ERR22 means the VFD received User-Defined Fault 2 from an external input or PLC logic.
Most common causes:
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External safety or interlock signal
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PLC or controller logic
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Misconfigured user-defined fault parameters
If you did not intentionally configure User-Defined Fault 2, disabling it is typically the correct solution.
