Mill Spindle C-Axis - Troubleshooting Guide

Introduction

This troubleshooting guide explains how to diagnose and resolve issues with a MIll Spindle C-Axis Drive.

The top image shows the following components of the Mill Spindle C-Axis Drive

Gasket Enclosure Cap
Enclosure Base
Gasket Square J-box
Servo Motor
Enclosure Block
Gasket Enclosure Base
Enclosure Cap

The bottom image shows the following components of the Mill Spindle C-Axis Drive

Mounting Plate
Shim Stack
Tooling Stop Block

Required Software Versions:

1.21.000.1130 or higher

Rotary Files for VMC:

Manual Rotary File: Mill SPDL C-AX-P20-V1
- No Tool Tip Tracking available
Automatic Rotary File: Mill SPDL C-AX-P20-V2
- Tool Tip Tracking available

Electrical Safety

DANGER: Working with the electrical services required for CNC machines is extremely hazardous and can result in serious injury or death.

Before connecting line wires to the CNC:

Turn off all power to the machine at the source.
Perform a Lockout-Tagout (LOTO) procedure to ensure the power remains off during service.
Verify that power has been disconnected by using an AC voltage detector on all incoming lines.

If you are uncertain about how to safely disconnect power or perform LOTO procedures:

Do not proceed.
Contact qualified personnel or obtain appropriate assistance before continuing.

Failure to follow these precautions may result in electrical shock, equipment damage, or fatal injury.

Danger: Before beginning any work inside the control cabinet, verify that the High Voltage indicator light on the 320V Power Supply / Vector Drive has been off for a minimum of five (5) minutes. This waiting period ensures that residual voltage has dissipated and reduces the risk of electric shock.

Certain service procedures involve high-risk electrical components and may pose serious injury or fatality hazards. Technicians must not attempt any procedure unless they have a complete understanding of the steps involved and the associated risks.

If there is any uncertainty regarding a procedure, contact your Haas Factory Outlet (HFO) to arrange for a qualified service technician.

Symptom Table

Symptom	Possible Cause	Corrective Action
Alarm 7.108 C AXIS SERVO OVERLOAD	The feeds and speeds are too high for the work.	Decrease the feeds and speeds.
	The cutting tool is not sharp or is damaged.	Install a new device or a new tool insert.
	There is a mechanical blockage in the axis of travel.	Make sure the axis has a clear path of travel.
	The servo amplifier has a problem	Troubleshoot the servo amplifier.
	Internal pressure is unable to escape	Email Haas Service.
Alarm 7.103 C AXIS SERVO ERROR TOO LARGE	The connection to the encoder or power is faulty.	Check the encoder and power cable connections to the motor.
The machined part has inaccurate features.	The feeds and speeds are too high for the work.	Decrease the feeds and speeds.
The machined part has inaccurate features.	The angle head tools were not properly calibrated	Refer to the Calibrate Angle Head Tools section in 23 - VF/VM - Spindle C-Axis Drive.
Alarm 175 GROUND FAULT DETECTED Alarm 552 TRIPPED CIRCUIT BREAKER	There is a short to ground in the axis motor cable.	Test the axis motor cable for short.
	There is a short to ground in the axis motor.	Test the axis motor for short.
Alarm 7.9918 C AXIS SERIAL ENCODER INTERNAL DATA ERROR Alarm 7.9922 C AXIS MOTION CHANNEL FAULT DETECTED Alarm 7.9923 C AXIS SOFTWARE DETECTED ENCODER FAULT Alarm 7.9930 C AXIS SERIAL ENCODER POOR COMMUNICATION Alarm 7.9959 C AXIS SERIAL ENCODER DISCONNECT Alarm 7.9948 C AXIS SECONDARY ENCODER SERIAL FAULT Alarm 7.9949 C AXIS SOFTWARE DETECTED SECONDARY ENCODER FAULT Alarm 7.9950 C AXIS SOFTWARE DETECTED SECONDARY ENCODER FAULT Alarm 7.9951 C AXIS SECONDARY ENCODER SERIAL COMMUNICATION FAULT Alarm 7.9960 C AXIS SECONDARY SERIAL ENCODER CABLE FAULT	The software is outdated.	Alarm is obsolete New alarm for encoder faults updated in software. Update to latest version 100.21.000.1130 or Higher; Added Alarms 9719 and 9720 for Encoder Fault Detection on Mocon Primary and Secondary Axis.
Noise when the unit is moving.	Incorrect parameters	NGC clear rotary models, cycle power and reselect the rotary model.
	no ferrites on the encoder and power cables.	Add ferrites to the encoder and power cable, and ensure the ferrite is not placed around the chassis ground cable.
	The unit crashed.	Contact HFO for repair options.
Alarm 9961 INVALID OR MISSING ROTARY FILE is generated after the software update.	Updated software to a version that does not include reverse rotary files while a reverse rotary file was enabled.	Follow the Reverse Rotary Direction Setup - NGC procedure to install and activate reverse rotary files.
Axis is commanded to move but does not move	The motor is not operating.	Contact your HFO for repair options
Positioning or accuracy errors	Machine level and geometry out of tolerance.	Have an HFO inspect the machine level and geometry and fill out a machine inspection report. Then, contact your HFO for repair options.
	Incorrect parameters enabled.	Make sure the correct set of parameters is in the machine. Then, make an error report and send it to Haas service.
	The rotary has crashed.	Contact your HFO for repair options.
	The angle head tools were not properly calibrated	Refer to the Calibrate Angle Head Tools section in 23 - VF/VM - Spindle C-Axis Drive.
Alarm 7.9719 C AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x1) Encoder Data Fault = (Alarm 9918 SERIAL ENCODER INTERNAL DATA ERROR)	Encoder signals are affected by noise from high power cables. (Faulty servo motor encoder.)	Refer to Serial Data Communication Faults / Electrical Noise section below. (Check the servo motor for coolant contamination.)
Alarm 7.9719 C AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x2) Encoder Internal Axis Fault 1 = (Alarm 9922 MOTION CHANNEL FAULT DETECTED)	(The motion channel has reported an internal fault of a type that is not recognized by the control)	Cycle power to the machine, If the issue persists, take an error report (Shift F3) and email to Haas Service
Alarm 7.9719 C AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x3) Encoder Internal Axis Fault 2 = (Alarm 9923 SOFTWARE DETECTED ENCODER FAULT)	(Software has reportrd an internal fault of a type that is not recognized by the control.)	Cycle power to the machine. If the issue persists, take an error report (Shift F3) and email to Haas Service
Alarm 7.9719 C AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x4) Encoder CRC Fault = (Alarm 9930 SERIAL ENCODER POOR COMMUNICATION)	(Encoder signals are affected by noise from high power cables.)	(Refer to Serial Data Communication Faults / Electrical Noise section below.)
Alarm 7.9719 C AXIS PRIMARY ENCODER SERIAL FAULT Alarm Subcode (0x5) Encoder Cable Fault = (Alarm 9959 SERIAL ENCODER DISCONNECT)	(Cables are not connected correctly or encoder is faulty.)	(Inspect the cables and connectors. Refer to the Main Processor/Encoder Cable section below.)
Alarm 7.993 C AXIS AMPLIFIER SHORT CIRCUIT	Coolant or liquid intrustion.	Inspect the motor for short circuit condition and determine the cause. If it is found to be coolant related, replace the enclosure gasket on the servo motor housing or apply RTV sealant to holes. Note: Be sure the RTV sealant has enough time to cure before coolant may come in contact with the rotary.

C-Axis Drive Check Valve

Early models of the C-Axis drive saw servo motor overload and poisition error too large alarms due to pressure buildup. A breather valve was added to the design to resolve this issue for future models. If the breather value [1] is not installed, contact Haas Service for assitance.

Serial Data Communication Faults / Electrical Noise

Sigma-5 servo motors, non-contact encoders output serial data signal to the control. If the serial data signal is missing or becomes unreliable the control will generate a serial data communication error. Electrical noise can cause the serial data signal from the encoder to become unreliable and cause false alarms. Follow the troubleshooting guide below to help eliminate the noise in the system.

Incorrect machine grounding. Make sure the ground wire size is correct. Also the ground wire should run all the way back to the electrical panel.
Noise from other equipment. Make sure the machine does not share it's electrical service with another machine.
Loose encoder data connectors at PCB or at the motor encoder, can cause the serial data to become unreliable. Refer to the Main Processor / Encoder Cable section.
Loose ground or high voltage power connectors will induce noise into the system.
- electrical cabinet check for loose connection at all the ground and high voltage power terminals (vector drive, wye-delta contactors, transformer..etc).
- pendant check for loose terminal connectors.
- spindle head check for loose ground and motor power terminals.
The ferrite filters suppress high frequency noise produced by the amplifiers and vector drive, when servos are on. Make sure they are installed in:
- Encoder data cables. Make sure there is a ferrite filter P/N 64-1252 installed in all the encoder data cables.
- Axis motor power cables. Make sure there is a ferrite filter P/N 64-1252 installed in X, Y, Z axis motor power cables [1].
- Spindle motor cables. Make sure there is a ferrite filter installed in the motor output of the vector drive.
  For a 40HP vector with 6 wire leads [1] use ferrite P/N 64-1254.
  
  For a 40HP vector with 3 wire leads [2] use ferrite P/N 64-1252.
  
  For a 20HP vector drive with 6 or 3 wire leads [3, 4] use ferrite P/N 64-1252.
Cable routing. Make sure that the encoder cable is separated from high power spindle/axis/pump cables.

Maincon PCB / Encoder Cable

Corrective Action:

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

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

If the pins have been pushed into the motor, you must replace the motor and cable together.

Make sure the cable is firmly connected at both ends. Reseat both connections. Make sure the cable is installed in the correct connector at the Maincon or MOCON PCB.