Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set User Manual

Page 740

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Section 15A

Troubleshooting The Control

15A-30

Faults

Axis Module

Description

PWR

The axis module hardware has faulted from an over current condition. The

current through the power output transistors is monitored. If the current

exceeds a fixed level (greater than 300% of controller rating) this fault will

appear. Typical causes are a shorted lead, motor malfunction, or

malfunctioning power IGBTs.

CRNT

One of the axis modules of your 1394 drive has been requested to provide

too much current. This is typically caused by: Accel/Decel command from the

CNC is requiring peak current for an excessive amount of time, the machine

friction or inertial/viscous load is excessive, the motor has been improperly

sized, a short circuit exists across the drive output terminals, logic supply

circuits have malfunctioned, or AC input is incorrectly wired.

VBUS

The DC bus supply was lost to the axis module. Check slider

connections/termination strip or there could be a blown link fuse.

TEMP

1

The 1394 contains a thermal sensor which senses the internal ambient

temperature. Causes could be: that the cabinet ambient temperature is

above rating. The machine duty cycle requires an RMS current exceeding

the continuous rating of the controller. The airflow access to the 1394 is

limited or blocked.

Faults

System Module

Description

VHI

The 1394 system module bus voltage exceeds the maximum operating

voltage. The DC power bus is continuously monitored. If it exceeds a preset

level (810 Vdc), a fault is sensed and the power supply is disabled. This can

be caused by an under sized shunt requirement, shunt regulator fuse has

blown, the shunt regulator transistor has malfunctioned, the power driver

board is malfunctioning and incorrectly sensing the bus voltage, the CNC

acc/dec rate is incorrectly set, the input line voltage is excessive, the system

inertia is too high causing excessive energy to be returned to the power

supply bus, or a vertical axis with insufficient counterbalancing is overdriving

the servomotor and causing excessive energy to be returned to the power

supply bus.

VLOW

The 1394 system module voltage does not meet the minimum operating

voltage. The DC power buss shall activate the under voltage limit when the

bus drops to 275 VDC or less. It will clear at 300 Vdc. Typical causes

include low voltage on the three phase input.

GRND

The 1394 system module has detected a ground fault. The system

generates a ground fault when there is an imbalance in the DC bus of greater

than 5A. This drive error can be caused by incorrect wiring (verify motor and

ground wiring), motor malfunction, or an axis module IGBT malfunction.

TEMP

1

The 1394 contains a thermal sensor which senses the internal ambient

temperature. Causes could be: that the cabinet ambient temperature is

above rating. The machine duty cycle requires an RMS current exceeding

the continuous rating of the controller. The airflow access to the 1394 is

limited or blocked.

PHASE

The 1394 system module has detected a loss of one of the input power

phases. The three--phase input line is monitored and a fault will be issued

when a phase loss is detected. Typical causes include, one or more input

line fuses have opened, contactor malfunction, or incorrect wiring.

1 Over Temperature Indicators are for the system module and axis modules only. They do not

reflect any motor over temperatures that may occur. Motor thermal switches (if available) should

be wired into the E-STOP string.

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