Source Stability Under Reactive Loads

In Constant Voltage mode, the NI PXI-4130 remains stable for most loads, even in the presence of low-equivalent series resistance (ESR) capacitors. However, when operating in Constant Current mode, particularly in higher current ranges, some inductive loads may cause the NI PXI-4130 source to become unstable, especially during high current operation. If the source becomes unstable, an oscillating or unregulated behavior can be observed across the output terminals. This situation yields excessive noise in the measurement, erratic behavior, or thermal shutdown.

After noticing any abnormalities, you can verify the behavior of your device by inspecting the voltage across the output terminals with an oscilloscope or a digitizer. To troubleshoot this issue, use the niDCPower Output Capacitance property or the niDCPower_ATTR_Output_Capacitance attribute to enable or disable the capacitor. For more information about operating your device under unstable conditions, refer to Output Capacitance Selection.