How to Solve Servo Alarm 2
  • 28 Dec 2020
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How to Solve Servo Alarm 2

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Zhafir Service Department Training Files
Servo alarm NO.2


As the voltage of DC bus is more than 500 volts, and the inverter capacitor discharge also take some time. So please be very careful while doing inverter-related operation.

Alarm principle:

When the voltage of DC bus lower than a certain value, occur NO.2 (E.UP ) alarm.


  1. Voltage input too low or not stable.
  2. DC fuse burned.
  3. KEB voltage inspection circuit failure.


  1. Check the input voltage to see if these is some abnormal.
  2. Check the DC fuse, for the mold, ejector, and charge axis, maybe it is the DC fuse burned, result in the low voltage.

3. Check the KEB voltage inspection circuit.

Measure the voltage between inverter “++”and “- -“interface whit multi-meter. (Normally it is more than 500V.) Then observe the RU18 (actual DC voltage) value through the controller, operator or a computer with HSP5 wire. If the actual voltage is higher than 500V, but the RU18 is less than 500V, then it is the inspection circuit failure, normally we need to replace the inverter. The following pictures shows how to observe then RU18 value through the controller.

Login the level 5, go to the KEB page, input “0212” on the ‘Parameter Nr.” text box, to see the voltage when the motor is off, and then turn on the motor, and see the parameter value. 

Fig 1 Ru18 value when motor is off

Fig 2 Ru18 value when motor is on

If it is need to replace the inverter, please see the instruction “How to replace a inverter.”

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