1. Alarm phenomenon

Siemens 840Dsl/828D CNC machine are usually equipped with S120 power supply and drive,they have built-in heat dissipation and external heat dissipation, and the heat dissipation is realized by fans. When the temperature reaches the specified value, the fan in the drive to start, and the running time of the fan is recorded inside the drive. At this time, the drive overheating alarm appears.

This phenomenon usually has the following situations:

(1) The ambient temperature of the electrical cabinet is too high, which is not conducive to driving heat dissipation

—The ambient temperature of the electrical cabinet needs to be improved, such as adding an external fan, air conditioner, etc.

(2) The fan is bad and needs to be replaced

—The fan needs to be replaced.

(3) Time monitoring of fan operation records arrives

—After replacing the fan, modify the running time value of the drive fan (clear the calculator).

(4) The drive itself is faulty.

—Replace the drive

2. Modification of parameters

Modify the drive fan running time value (the calculator is cleared), the parameter is P251, in the drive parameters, in the debugging interface --> machine data ---> drive data, find the drive that alarms, and search for the parameter P251. This parameter is the power unit fan running time counter. No matter how much the original value is, modify it to zero and save it.

But sometimes it will be wrong to modify this parameter. This is because for the activated controller not allowed to modify the drive parameters. At this time, the drive needs to be inactivated. There are three ways to make the drive in an inactive state according to different machine:

(1) Emergency stop to make the drive inactive. But this method is not feasible for many machine , because the machine wiring and functions in different machine factories are different.

(2) Pull out the X21 terminal of the power module and disconnect the EP enable.

(3) Pull out the X122 terminal of the NCU and disconnect OFF1 and OFF3.

The above three methods are to make the drive in the inactive state so that the parameters can be modified. After the modification is completed, the parameters are saved, the pulled-out terminal is restored, the emergency stop is released, and the enable is re-enabled.

3. Matters needing attention

It is necessary to ensure a good working environment for the power supply and drive, and the hardware may be damaged if the ambient temperature is too high.

4. Conclusion

Siemens software provides a very powerful debugging function, and proficient in on-site fault diagnosis, program debugging and application will bring great help to your work. But the use of software tools must pay attention to detailed records and complete backups.

Dalian Indus Machinery Technology co.,ltd www.indmt.com