3.2 Power Budget Calculation and Allocation
Before installing the module, it is necessary to calculate the total current of all peripheral modules on each voltage rail and ensure that it does not exceed the total capacity of the chassis (standard version with a total power of 500W, high-power version with 1000W). Pay special attention to the+12V rail - many RF and digital modules consume a lot, with the standard version having a maximum of only 5.5A/module for+12V. The total capacity of two modules connected in parallel can reach 11A (but current sharing and redundancy need to be considered). If a module single track exceeds the limit, it may trigger power protection.
3.3 Redundancy and Hot Plug
The standard version of the two power supplies adopts a current sharing working mode. When one fails, the other can temporarily bear all the load (but the capacity may be insufficient, it is recommended to use it at a reduced capacity). The four power supplies of the high-power version are equally distributed and support 3+1 redundancy (any damage does not affect system operation). All power modules support hot swapping - without shutting down, simply unplug damaged modules and insert new modules to automatically integrate into the system.
3.4 Power control and monitoring signals
Multiple control/status interfaces are provided on the backplane (see Appendix B for details):
INH # (J6): External prohibition signal, can remotely turn off DC output.
RST # (J8): System reset signal input.
FAL # (J9): Power failure input, used for external monitoring.
J5: LED power status connector, indicating whether each voltage rail is normal.
CN5 (SMBus): System management bus, connected to system slot P2, can query power health status, temperature, etc.
JP1:10MHz reference clock selection jumper - default internal clock. If an external clock is required (via PXI_CLK10-IN in Slot 2), move the jumper to pins 2-3.
Cooling System and Thermal Management
PXIS-3320 is equipped with 10 80 × 80 × 25mm double ball bearing fans, divided into upper and lower layers:
Bottom 5 fans: used for air intake (cold air is drawn in from below).
Top 5 fans: used for exhaust (hot air is discharged from above).
The total air volume is up to 482 CFM (241 CFM per floor), the speed is 4000-5000 RPM, and each fan consumes 2.64W (12V power supply). Such strong airflow ensures that the internal temperature of the chassis remains uniformly cooled even at an ambient temperature of 50 ℃, effectively protecting high heating modules.
The fan tray can be directly pulled out from the front panel (hot swappable), and each tray has an independent LED indicating the working status (normally on, flashing indicates a fault). When the fan fails, the system alarm buzzer sounds and the front panel fan LED flashes, reminding maintenance personnel to replace it.
Front panel monitoring and alarm system
Three sets of LED indicator lights are provided in the upper right corner of the front panel:
Power (green): Constant light indicates that all DC voltages (+3.3V,+5V,+12V, -12V) are outputting normally.
Temperature (red): Constant brightness indicates that the internal temperature is less than 50 ℃; Flashing indicates temperature>50 ℃ (warning).
Fan (amber): Always on indicates normal fan speed; Flashing indicates at least one fan malfunction.
In addition, the chassis is equipped with a built-in buzzer that emits a continuous beep sound when there is any abnormality in the power supply, temperature, or fan. The front panel is equipped with an "Alarm Reset" button. When pressed, the buzzer stops sounding and the alarm system is reset. But if the fundamental problem is not resolved, the alarm will be triggered again in a few minutes.

Hardware installation steps and grounding strategy
6.1 Installation process
Place the chassis on a stable flat surface (desktop or rack), ensuring that the bottom and top ventilation openings are unobstructed.
Confirm that the power switch is in the OFF position (the switch protrudes from the panel).
Connect the AC power cord to a well grounded socket.
Install the system controller module:
Release its ejector/injector handles.
Slide smoothly along the upper and lower guide rails until the handle automatically locks, then tighten the front panel fixing screws.
Install each peripheral module in sequence (also fixed with a handle).
Press the power switch on the front panel (ON when pressed), and the green Power LED will light up, indicating that the fan is running.
If there is no response after pressing, refer to the "Troubleshooting" section below for handling.
6.2 Grounding and Isolation
The installation holes on the backboard are divided into two categories:
GND (circular pad): connected to the signal ground plane.
FGND (Square Solder Pad): Connected to the power ground (earth) and isolated from the signal ground.
When leaving the factory, the backplane is fixed to the chassis through FGND mounting holes, so the signal ground is isolated from the chassis ground, which is conducive to eliminating ground loop interference. If the application requires short circuiting the signal ground to ground (such as reducing common mode noise), the GND can be short circuited to the FGND pad through an external jumper (caution should be taken as it may increase the ground loop current).