1187

Common Causes

• Inverter unit control board fault slowing the stop response
• NC software problem with the emergency stop timing
• Excessive inertia or load preventing the axis from decelerating in time

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code 1 = Emergency stop time over; code 2 = Deceleration time over at emergency stop; code 3 = Deceleration time over at alarm stop
2. 2Read the code: 1 means emergency stop time over, 2 means deceleration time over at emergency stop, 3 means deceleration time over at alarm stop.
3. 3Note which axis or spindle is named in the object field and whether the machine was cutting heavy at the time.
4. 4Test the emergency stop on the named axis with the machine light: if it still overruns the preset time, the braking circuit or inverter control board is suspect.
5. 5Lock out and discharge the DC bus before inspecting the braking resistor and its connections for the named axis.
6. 6If the hardware checks out, the probable faulty locations are the inverter unit control board or NC software; record the code and contact Okuma service.