What causes an encoder fault (Axis Unit display codes "A5, d0, d2, d7") and what can I do to prevent it from happening?

Encoder faults are the result of the controller not receiving the signals from the encoder correctly.  They can result from the following conditions;

• Motor stalling due to high fastening torque beyond tool capacity
• Broken Motor cable
• Broken Encoder cable
• Broken Encoder
• "Crashing" of motor from high speed (FRN) to torque speed (TQ) during fastening on "hard" (low fastening angle) joint applications

If you experience broken cables, it is most likely due to wear or stress placed upon the cable at the break point.  Alleviate any binding or pinching of cable.  The cables should be free from stress & hang freely allowing free movement.  Cable ties should be eliminated where possible.

On "hard" joint applications, the encoder is susceptible to high inertial G-force & shock at high speeds as it tries to slow down to torque speed. In time, this shock can damage the encoder disk causing an encoder failure.  It is recommended on these applications, that Free Run Speed (FRN) be set at no more than 80% of maximum rated speed.  It is also recommended that a "Time Wait" instruction be used in the fastening sequence (set from the "SET SEQUENCE" Menu) when any direction change of the motor is required from CW to CCW or vice versa.  (Time should be set to min. 2 (0.2sec)).  This allows time for the motor to ramp down before changing direction.

From section 9.4.5 of the manual.
ENCODER ANGLE PULSE ABN.
 

<Error Description>
An ANGLE signal is not being received while the motor is supposed to be turning. When this error message is displayed on the CRT, the affected Axis Unit display should be checked for an Abnormal code. Refer to Section 9.6 of the manual for more information regarding this failure type.

<Check Items>

• Check the SET PARAMETER screens and verify that the settings do not result in a Duty Cycle higher than 50%, and that the resultant Cycle Time is not less than 12 seconds.
• Check the connected Axis Units for any abnormal indications. If all spindles appear to be affected, the problem is likely to be found in another System component.
• If the problem appears to be a common fault, verify correct input power to the Axis Units.
• If the problem only affects a single spindle, perform an encoder test procedure as provided in Section 8.2.2 of the manual.
• If the encoder test identifies a problem, exchange the tool, cables and/or the Axis Unit until the cause of the problem is identified.
• If the encoder test does not identify a problem, verify the Axis Unit input voltage and ensure that the power cable is properly connected.
• If problem still exists, replace the affected AXIS Unit.  Refer to Section 8.3 of the manual for more detailed information.
• If problem still exists, replace the affected tool.  Refer to Section 8.3 of the manual for more detailed information.

If this did not answer your question or problem, please contact our support department via email, contact form or call (586) 781-2100

[ Back ] [ Up ] [ Next ]