Danfoss FC302 ALARM 15 — What It Means
ALARM 15 on a Danfoss VLT AutomationDrive FC 302 indicates a hardware mismatch. The drive has detected that a fitted option card or accessory is not compatible with the present control card hardware or software. Danfoss describes this as a non-compatible option installed.
This is not a power fault or motor problem. It means an option module (communication card, brake option, I/O accessory, or other add-on) does not match the exact FC 302 hardware configuration, control board version, or firmware. The drive will not operate normally until the mismatch is resolved.
Common Causes
- Wrong option type for drive model The installed accessory card is not supported by this exact FC 302 hardware and software combination.
- Option not compatible with control board The option card does not match the control card or firmware version installed in the drive.
- Poorly seated or loose option module The option card is not fully inserted or has lost mechanical contact with the control board.
- Firmware version mismatch The option software version is incompatible with the drive’s control card software version.
- Defective or damaged option card The option itself is faulty or has failed and no longer communicates properly with the control platform.
Step-by-Step Fix
- Make the drive safe before any service. Stop the motor, isolate AC mains and any remote DC-link supplies, and wait for the DC bus capacitors to discharge completely.
- Identify all fitted option cards. Check what communication, brake, I/O, or accessory modules are installed in the drive and note their model numbers and labels.
- Record drive identity data. Write down the FC type code, power section, voltage rating, software version, control card software ID, power card software ID, option mounted, and option software version for later reference.
- Remove and reseat the option card. Power down the drive, pull the suspect option module fully out, inspect the connector pins and socket for damage or debris, then reinstall it firmly and restore power.
- Remove the option and retest. If reseating does not clear the alarm, remove the option card entirely and power up the drive without it to confirm whether ALARM 15 disappears.
- Swap with a known-compatible option. If available, install a verified compatible replacement option card to confirm whether the original accessory is defective or mismatched.
- Contact Danfoss support with recorded data. If the alarm persists with correct hardware or you cannot determine compatibility, provide Danfoss the identity data from step 3 for exact hardware and software pairing guidance.
Parts Often Needed
| Part | Notes |
|---|---|
| Danfoss FC 302 option card or communication module | Amazon | Match exact part number to your drive’s control card and firmware version. |
| Danfoss FC 302 control card | Amazon | Required only if option compatibility cannot be resolved and control board is confirmed faulty. |
When to Call a Pro
Call a qualified Danfoss service technician or drive specialist if the alarm does not clear after reseating or removing the option, if you cannot identify which option is installed, or if you do not have access to the drive’s software version data. ALARM 15 requires exact hardware and firmware compatibility data that Danfoss support may need to interpret. A professional can verify option part numbers against the control platform, update firmware if needed, and source the correct replacement module for your specific FC 302 configuration.