SRVO-068: DTERR alarm (pulse coder no response)

What it means

The serial encoder didn't answer the controller's data request - a communication failure on the feedback line. The suspects run from a loose connector to a damaged cable to the encoder itself, in roughly that order of cost. One trap: a ground fault on the encoder battery line can throw DTERR on a DIFFERENT axis than the damaged cable, thanks to noise.

Common causes

Ranked by what technicians most often find, most likely first.

1. Loose feedback connectors at the amplifier or motor.
2. Feedback cable shield not grounded properly in the cabinet.
3. Damaged mechanical-unit or robot-connection cable.
4. Failed pulse coder (motor replacement).
5. Amplifier fault.
6. Cross-axis ghosting: a grounded battery line in one axis's encoder cable alarming a different axis.

How to fix it

1. Reseat the feedback connectors at the amplifier and motor ends.
2. Verify the cable shield is securely grounded in the cabinet.
3. Test the mechanical unit cable per the maintenance manual's alarm troubleshooting; replace if faulty.
4. Then, in order of cost: motor (re-master after), amplifier, robot connection cable.
5. If the alarmed axis checks out clean, remember the cross-axis noise trap and inspect the other encoder cables. Power-cycle to clear.

Related codes

• SRVO-067OHAL2 alarm (pulse coder overheat)
• SRVO-069CRCERR alarm (pulse coder data corrupt)
• SRVO-066CSAL alarm (pulse coder checksum)
• SRVO-070STBERR alarm (pulse coder framing error)
• SRVO-071SPHAL alarm (feedback speed excess)
• SRVO-072PMAL alarm (pulse coder fault)
• SRVO-063RCAL alarm (rotation counter abnormal)
• SRVO-073CMAL alarm (pulse coder noise/fault)