LAST UPDATED: 03/27/2020

Spindle Encoder - Troubleshooting Guide - NGC

IntroductionEncoders are used on Haas Machines to give feedback to the control about the direction and speed of the spindle. AHaas machine will alarm if any of the encoder signals are lost or are not responding to machine inputs. If the encoderis not generating an alarm it does not usually need to be replaced. Use this guide to troubleshoot spindle encoderrelated symptoms and alarms.

Non-Contact Encoder Troubleshooting

Spindle Encoder - Troubleshooting Guide - NGC

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Symptom Table

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SYMPTOM / ALARMS POSSIBLE CAUSE CORRECTIVE ACTION

The Spindle MotorDoes Not Turn, andThe Load MeterStays at Maximum.

The Wye-Deltacontactors are notoperating correctly.

Command a spindle speed of 50 RPM, make sure the Wye contactorengages, if not refer to the Wye-Delta Contactor - TroubleshootingGuide - NGC

The Spindle Turns atThe Low RPM and TheLoad Meter Stays NearThe Maximum

Encoder Alignment isnot correct

Inspect the Radial runout, the encoder gapping and the axial positionof the read head relative to the encoder ring. See the Encoder Ring toRead Head Alignment section below.

The spindle encodercable (M8) metalthreaded ferrule isnot connected to thecable shield.

Look at the spindle encoder cable M8 connector. Replace the encodercable if the metal ferrule is not connected to the cable shield.

Loose encoder cableconnection. Theencoder cable isdamaged.

Check the encoder cable and connection. See the Main Processor/Encoder Cable section below.

The encoder read-head is not groundedcorrectly.

See the Non-Contact Encoder Read Head Grounding section below.

The encoder cable ismissing the ferritefilter.

Make sure the spindle encoder cable has a ferrite filter installed.Alarm 4.9930 SERIALENCODER POORCOMMUNICATION

The Non ContactEncoder mountingplate is poorlygrounded.

Verify that the NCE mounting plate is grounded. If the alarm isintermittent check that the mounting plate is made out of steel, if themounting plate is made out of aluminium contact the servicedepartment for the part number to upgrade to steel..

Alarm 4.9959 SERIALENCODERDISCONNECT

Loose encoder cableconnection. Theencoder cable isdamaged.

Check the encoder cable and connection. See the Main Processor/Encoder Cable section below.

Alarm 4.9918 SERIALENCODER INTERNALDATA ERROR

Encoder Alignment isnot correct

Inspect the Radial runout, the encoder gapping and the axial positionof the read head relative to the encoder ring. See the Encoder Ring toRead Head Alignment section below.

Spindle Encoder - Troubleshooting Guide - NGC

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The encoder read-head is not groundedcorrectly.

See the Non-Contact Encoder Read Head Grounding section below.

Bearingless TSC unioncarbides are worn outand no longer parallelwhich flexes the read-head away from thering.

Replace the bearingless union.

Encoder Alignment isnot correct

Inspect the Radial runout, the encoder gapping and the axial positionof the read head relative to the encoder ring. See the Encoder Ring toRead Head Alignment section below.Alarm 4.103 S

(SPINDLE) AXIS SERVOERROR TOO LARGE

The encoder ring isdamaged.

Use a magnetic field viewer card to check the encoder ring. See theNon-Contact troubleshooting video.

Encoder Alignment isnot correct

Inspect the Radial runout, the encoder gapping and the axial positionof the read head relative to the encoder ring. See the Encoder Ring toRead Head Alignment section below.

The encoder ring isdamaged.

Use a magnetic field viewer card to check the encoder ring. Seethe Non-Contact troubleshooting video.Alarm 4.153 SP-AXIS

ZERO CHANNELMISSING

The servicepatch_VH_783 isapplied and themachine has a non-contact encoder.

A service patch VH_783 was made to allow technicians to jog an axison the machine without generating a spindle encoder alarm. Thispatch needs to unistalled after the repair is completed. In servicemode go to DIAGNOSTICS\Parameters\Patches and verify that patchVH_783 is not applied. Refer to Patch File Load Uninstall - NGC.

Main Processor/Encoder Cable

Corrective Action:

Examine the connector [1] on the Maincon PCB.Make sure it is not damaged.

Examine the cable. Look for signs of damage orstiffness. The connector [4] has two housings[2,3] for the cable pins.

Measure the resistance on the encoder cablefrom leg to leg, and from leg to ground. Makesure each measurement results in an openconnection.

Make sure the cable is firmly connected at bothends. Reseat both connections. Make sure thecable is installed in the correct connector at theMaincon PCB.

Spindle Encoder - Troubleshooting Guide - NGC

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Non-Contact Encoder Read Head Grounding

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Read Head and Casting

1. Disconnect the cable from the encoderread head.

2. Use a multimeter and check thecontinuity between the read-head screwand the casting.

3. If there is little or no continuity:

• make sure the grounding cable to thespindle head casting is secured.

• make sure the mounting screws aremaking contact with bare metal and notthe anodized layer.

Connector Case and Read Head

1. Check the continuity between the readhead connector case [2] and the readhead [1].

2. If there is little or no continuity:

• remove the jamnut from the M8connector and install an M8 internalstar washer onto the connector.

• install and tighten the jamnut over theM8 star washer and install the read-head back onto the mounting bracket.

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Encoder Ring to Read Head Alignment

Electrical Diagram

Proper alignment of the read head to theencoder ring is critical. The alignment willvary based on the brand of encoder. Usethe chart provided to make sure theencoder ring and read head are properlyaligned.

VENDOR RLSBAUMER

A 0.020" +0.020 / -0.0390.0453" +/- 0.019

B 0.0118" +0.0079 / -0.00390.0118" +/- 0.0039

C 0.362".0360"

Incorrect installation of the spindle mayaxially misalign the motor shaft. Measurethe distance from the top of the motor shaftto the top of the motor cooling fins. Itshould be 1.291 ± .005.

If the shaft is axially misaligned the spindlemotor must be replaced.

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