| Abnormal Communication | Abnormality for communication of frequency inverter and other equipments |
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ERR14 – Abnormal Communication
What this means
ERR14 indicates a communication failure between the VFD and an external device.
In most CNC setups, this means the VFD is not successfully communicating with the CNC controller or control software using the expected protocol and settings.
The VFD itself and the spindle motor are usually fine.
Why This Happens
Modern VFDs can be controlled via external communication such as:
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RS-485 (Modbus)
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PWM + direction
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Analog 0–10V
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Controller relay logic
ERR14 occurs when the VFD expects valid communication data but:
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Receives nothing
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Receives corrupted data
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Receives data using the wrong protocol or parameters
Most Common Causes We See
1. Communication wiring issue (most common)
Examples:
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Loose or reversed communication wires
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Incorrect terminals used
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Broken or damaged communication cable
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Missing ground reference
Even a single swapped wire can prevent communication.
2. Incorrect communication parameters
Common parameter mismatches:
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Baud rate
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Address / slave ID
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Data bits
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Stop bits
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Parity
Both the VFD and controller must match exactly.
3. Wrong control mode selected
If the VFD is set for:
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RS-485 control but the controller is sending analog/PWM, or
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Analog control but software expects serial communication
ERR14 can trigger immediately.
4. Controller or software not running
If the CNC controller:
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Is powered off
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Is in fault or e-stop
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Has not initialized spindle control
The VFD may time out and report a communication fault.
5. Noise or poor cable routing
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Long unshielded communication lines
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Routing next to motor or spindle cables
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Missing shield grounding
This can cause intermittent ERR14 faults, especially during motion.
What to Check First
Step 1: Identify how your spindle is controlled
Confirm whether your setup uses:
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Analog 0–10V
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PWM
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RS-485 / Modbus
The VFD and controller must be configured for the same method.
Step 2: Inspect communication wiring
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Verify correct terminals are used
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Confirm polarity where applicable
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Check for loose or damaged wires
Step 3: Verify communication parameters
On both the VFD and controller/software:
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Baud rate
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Address
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Protocol type
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Data format
These must match exactly.
Step 4: Test manual operation
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Switch the VFD to local/manual mode
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Run the spindle from the keypad
If it runs normally, the issue is confirmed to be communication-related, not mechanical or electrical.
Step 5: Temporarily simplify
If possible:
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Disconnect external communication
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Run in manual mode
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Reintroduce communication step-by-step
This isolates the failure point.
What ERR14 Is Not
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Not a spindle motor fault
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Not a cutting load issue
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Not an over-current or voltage fault
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Not caused by tooling or feeds
ERR14 is almost always configuration, wiring, or protocol related.
Summary
ERR14 means the VFD cannot properly communicate with an external device.
Most common causes:
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Incorrect wiring
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Parameter mismatches
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Wrong control mode selected
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Controller or software not ready
Start by verifying control method and communication settings before changing anything else.
