NI-DCPower Overload Protection Error (OLP) Codes

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Overload Protection errors (OLP) occur when a fault condition occurs that causes an SMU to exceed its operating limits. This causes the SMU to enter a protection state and generate a software error.

 

There are a variety of different types of faults that can cause an OLP error. In older versions of the NI-DCPower driver, all these faults would result in the same error code.

 

Starting with NI-DCPower 20.5, the driver returns more granular errors so that different types of faults result in different error codes. This document explains what causes these different error codes so that you can debug these errors in your application.

Contents

Summary of Error Codes

The following table summarizes all the different types of OLP errors that are reported for NI-DCPower 20.5 and beyond.

OLP Error Codes for NI-DCPower 20.5 and beyond

Error Code

OLP Error Type

Error Condition Summary

-1074118481

Overvoltage

An overvoltage was detected. This can occur if an external source drives the device beyond its operating voltage range.

-1074118480

SourcingLimitsExceeded

The device attempted to source too much power for too long. This can occur if the energy limits for extended range pulsing are exceeded.

-1074118479

SinkingLimitsExceeded

The device attempted to sink too much power for too long. This can occur if the energy limits for extended range pulsing are exceeded.

-1074118478

CurrentMeasurementShuntOverpower

The device detected too much current flowing through the measurement shunt for too long. This can occur if the power associated with an extended range pulse exceeds the device protection limits.

-1074118477

Overcurrent

An overcurrent was detected. This can occur if excessive current flows for long enough to exceed the device protection limits.

-1074118476

SinkingPowerExceeded

The device attempted to sink too much power. This can occur if the power associated with sinking current exceeds the device protection limits.

-1074118475

FullRangeOvervoltage

An overvoltage was detected. This can occur if a voltage is detected at the output that exceeds the device limits.

 

For previous versions of NI-DCPower, there was only a single OLP error (-1074118575) for all the different possible causes above. 

Causes of Each Error Type

Overvoltage

A voltage was detected at the output that exceeds the device protection limits. Overvoltage errors can occur due to a direct connection to an external voltage source. In addition, this can occur when hot switching channels through external relays. For example, sourcing current into an open relay will cause the SMU output voltage to float toward its voltage limit. Closing the relay may then cause a voltage spike resulting in an Overvoltage error.

To fix this, refer to the recommendations and best practices in Understanding Compliance and Protection Errors.

SourcingLimitsExceeded or SinkingLimitsExceeded

Extended range pulsing allows you to source or sink power beyond the DC limits for a short amount of time. The SourcingLimitsExceeded or SinkingLimitsExceeded errors occur due to a combination of:

  • Pulse Power (Voltage * Current) too high
  • Pulse Energy (Pulse Power * Pulse On Time) too high
  • Duty-Cycle (Pulse On Time vs. Off Time) too high


These two error types are similar, the only difference is whether the error occurs during sourcing or sinking. To prevent either error, reduce the voltage, reduce the current, reduce the on time, or increase the off time.

CurrentMeasurementShuntOverpower

The device performs current measurements by passing current through a shunt resistor. There are limits to how much power can be dissipated in this resistor for how long. This error occurs if too much current flows through this resistor for too long.

To prevent this error, reduce the current pulse amplitude or duration.

Overcurrent

An overcurrent was detected that exceeds the device protection limits. This SMU tries to regulate current to keep it within limits during normal operation. However, sometimes current spikes can occur due to switching relays or sudden changes in load resistance.

To fix this, refer to the recommendations and best practices in Understanding Compliance and Protection Errors.

SinkingPowerExceeded

The device attempted to sink too much power. This is similar to the SinkingLimitsExceeded error, except that the SinkingPowerExceeded error occurs primarily due to the peak pulse power. So, a single short high-power pulse may cause a SinkingPowerExceeded error, while a series of lower power pulses over a period of time may cause a SinkingLimitsExceeded error.

To prevent this error, reduce the sinking voltage or current.

FullRangeOvervoltage

This error is similar to an Overvoltage error. The only difference is that this error occurs for cases where the user has not provided their own Overvoltage protection limit (OVP Limit). So, this error indicates that an overvoltage was detected that exceeded the device maximum protection limits.

To prevent this error, reduce the maximum voltage driven into the device.

Handling Failures

Refer to the Handling Failures section of Understanding Compliance and Protection Errors.