SD700 servo drive alarms during operation and the fault code is er320

Fault Name: 

Er.320 (regeneration overload).

Fault Symptom: 

SD700 servo driver alarms during operation and the fault code is Er320.

Causes:

Drive bus voltage detection circuit failure;

Built-in regenerative resistor and built-in braking resistor own insufficient power;

Insufficient resistance or power of external braking resistor;

Select built-in regenerative braking wiring, but Pn012 (external braking resistor power) is not zero;

The servo brake tube is damaged.

Solutions:

Step 1:    In the case of no alarm, check whether the monitoring parameter Un140 (bus voltage) is consistent with the actual input voltage value through the host computer or the button. If there is a large difference between them, it can be determined that the driver bus detection voltage loop is faulty and you could detect the hardware failure circuit or device;

Step 2:    Check the fault information through the host computer that whether the main circuit bus voltage reaches the regenerative braking voltage value (220VAC drive regenerative braking voltage is 380Vdc, 380Vac drive regenerative braking voltage is 700Vdc; the regeneration load rate reaches 100%; if the corresponding value is not reached, therefore it can be determined as a driver software problem and you can feedback it to the relevant software engineer;

Step 3:    When the built-in regenerative braking resistor is selected, check if the monitoring parameter Pn012 is zero by the host computer or the button (When Pn012=0, the default is to select the built-in regenerative brake);

Step 4:    Check whether the built-in regenerative braking resistor has burned out or the regenerative braking time is short; check if the main circuit bus voltage value and regeneration load rate reach the corresponding values through the fault information, indicating the built-in regenerative resistor and built-in braking resistor power are insufficient, it is recommended that customers use an external braking resistor;

Step 5:    Select an appropriate external braking resistor - Note that the parameter Pn013 (external braking resistor resistance) unit is mΩ, Pn012 (external braking resistor power) unit is 10W, and the power needs derating: general derating by self-cooling mode is 20%, Strong wind cooling method derating is below 50%;

Step 6:    After changing to an appropriate external braking resistor, Er.320 will still be reported. It can be confirmed as a fault in the hardware circuit or brake pipe. You need to replace or repair it.

Analysis:

When the servo motor is in braking, the energy will feedback and the bus voltage will increase. When the ARM detects that the bus voltage (monitoring parameter Un140) reaches the regenerative braking voltage value, the brake pipe is turned on, so that the energy on the main circuit capacitor is discharged through the external braking resistor. The Er.320 processing method in the software calculates the cumulative regenerative energy through the bus voltage. The accumulated energy is equal to the braking energy minus the released energy and is reflected in the monitoring parameter Un00B (regeneration load rate). When the braking energy is greater than the released energy when the regenerative energy is accumulated over a period of time, the regeneration load rate reaches 100%, and a regeneration overload failure will be reported.