Chassis Considerations
NI PXI modules are designed to operate in a PXI/Compact PCI chassis at specified environmental conditions. Device performance and reliability may be limited at temperatures above the specified operating range. For best performance, take the following precautions:
- Ensure that the ambient temperature is within the temperature listed in the specifications document for your module, and that the temperature is stable (±5 °C).
- Follow standard metrology practices.
- Use a PXI chassis with a well designed cooling system.
Operating the module outside the specified operating temperatures can increase bias currents in the electronic components, increase noise, accelerate drifts, and decrease product life. Beyond the maximum specified operating temperatures, the circuits perform differently than during the factory calibration, resulting in additional measurement errors which may not be accounted for by the Tempco specifications.
To minimize the temperature rise above ambient, position the chassis away from heat sources and clean the PXI/Compact PCI chassis air filter at regular intervals. Clean air filters are essential to ensuring that the devices operate at peak performance.
Operating under high humidity or dusty conditions can cause leakages between circuit components to increase and result in additional measurement errors.
Chassis Cooling Guidelines
Follow these guidelines to optimize cooling and ensure best performance and reliability:
- Always run chassis with fans set on high. In newer NI chassis the settings are "HIGH" and "AUTO". On some older NI chassis the fan settings may be "HI" and "LO".
- Cover all empty slots in the chassis with a blank EMC slot filler panel.
- Remove and clean the inlet filters often to prevent buildup of dust and other foreign material that may restrict airflow.
- Locate the chassis such that the fan inlets and outlet vents are not obstructed. Keep other objects and equipment a minimum of 3 inches sway from the fan inlets.
For more information regarding cooling considerations, refer to your chassis documentation.