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Heidenhain Controller
Servo/Axis · Intermediate · 30-120 minutes
HEIDENHAIN 231-9320 - 9320 Position encoder: EnDat 2.2 not possible
Alarm 231-9320 occurs when the TNC control expects an EnDat 2.2 encoder based on machine parameters posEncoderType or motEncTyp, but cannot establish proper EnDat 2.2 communication protocol. This typically results from encoder hardware failure, cable issues, or parameter misconfiguration.
231-9320
HEIDENHAIN 231-9320 - 9320 Position encoder: EnDat 2.2 not possible
9320 Position encoder: EnDat 2.2 not possible
This TNC 640 error indicates an issue with the encoder system for axis. The control has detected a problem with encoder signals, possibly due to contamination, cable damage, or encoder hardware failure.
Root Cause Summary
Alarm 231-9320 occurs when the TNC control expects an EnDat 2.2 encoder based on machine parameters posEncoderType or motEncTyp, but cannot establish proper EnDat 2.2 communication protocol. This typically results from encoder hardware failure, cable issues, or parameter misconfiguration.
Safety
- Refer to Heidenhain service manual
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Check encoder LED status
Examine the EnDat encoder for any status LEDs. A red or no LED typically indicates encoder failure.
Ensure machine is powered down before physical inspection
- 2
Verify encoder power supply
Using multimeter, check +5V DC supply at encoder connector pins. EnDat 2.2 requires stable 5V ±5% for proper operation.
Check both no-load and loaded voltage conditions
- 3
Test with known good encoder
Temporarily substitute with identical EnDat 2.2 encoder to confirm hardware failure. Clear alarm and test axis movement.
Match exact encoder resolution and specifications
- 4
Document encoder serial number
Record failed encoder model and serial number for replacement ordering and warranty claims.
Call a technician if:
- ·Encoder replacement required
- ·Drive amplifier repair needed
- ·Parameter changes cause axis instability
Prevention
- Regular EnDat cable inspection during PM
- Maintain proper cable routing in cable chains
- Monitor encoder temperature in harsh environments
- Keep spare EnDat cables in inventory
Common Mistakes
- Confusing EnDat 2.1 and 2.2 parameter settings
- Ignoring cable bend radius requirements
- Not checking shield grounding
- Assuming encoder failure without cable testing
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Always verify with your machine manual or a certified technician before performing service procedures.