|NI-DCPower (English | Japanese)|
The NI PXIe-4136/4137 features configurable transient response settings for flexible load compensation of the output control loop.
Configurable transient response allows you to accommodate loads that might otherwise induce instability while allowing optimization for speed with more benign loads. It is independently selectable on the NI PXIe-4136/4137 using the niDCPower Transient Response property or the NIDCPOWER_ATTR_TRANSIENT_RESPONSE attribute.
The following table lists the transient response settings available for the NI PXIe-4136/4137.
|Slow||Slow transient response time|
|Normal||Normal transient response time|
|Fast||Fast transient response time|
|Custom (NI PXIe-4137 only)||Custom transient response time. Refer to Configuring Transient Response for detailed information about this option.|
The transient response of the NI PXIe-4136/4137 is determined by three parameters: Gain-Bandwidth (GBW) Product, Compensation Frequency, and Pole-Zero Ratio PZR). These parameters have separate values for each range for voltage control and for current control.
Set the niDCPower Transient Response property to Custom or the NIDCPOWER_ATTR_TRANSIENT_RESPONSE attribute to NIDCPOWER_VAL_CUSTOM to independently configure these parameters on the NI PXIe-4137 within certain ranges. If Custom is not selected, the values of these parameters are preselected depending on the setting of the niDCPower Transient Response property or the NIDCPOWER_ATTR_TRANSIENT_RESPONSE attribute.
GBW sets the overall gain of the control loop of the NI PXIe-4137 when the niDCPower Transient Response property is set to Custom or the NIDCPOWER_ATTR_TRANSIENT_RESPONSE attribute is set to NIDCPOWER_VAL_CUSTOM. Higher values give faster response but poorer stability.
To add poles and zeros to the NI PXIe-4137 control loop when the Transient Response property is set to Custom you can use Compensation Frequency and Pole-Zero Ratio. The Compensation Frequency and Pole-Zero Ratio properties can be used to stabilize an unstable (or oscillating) output signal. Pole-Zero Ratio sets the ratio of the pole frequency to the zero frequency, and Compensation Frequency is the geometric mean of the pole frequency and the zero frequency. It is the frequency of maximum phase shift caused by the pole-zero pair. You can use these two parameters to add lead compensators or lag compensators to the NI PXIe-4137 control loop to optimize performance. A lag compensator has the Pole-Zero Ratio set to a value less than 1.0, and a lead compensator has Pole-Zero Ratio set to a value greater than 1.0. If Pole-Zero Ratio is set to exactly 1.0, the pole and zero cancel each other and have no effect.