NI SCXI Chassis Configuration and Installation Guide

Important warning: When replacing fuses, it is necessary to use fuses of the same type and rating, otherwise it may cause equipment damage or fire hazards. Before disassembling any cover or fuse, be sure to disconnect the power cord.

Chassis installation and module insertion

1. Installation location requirements

Place the chassis on a stable and horizontal surface, leaving at least 10 cm (4 inches) of space behind to ensure smooth fan intake.

For SCXI-1000DC, if using screw terminals for power supply (early versions), strict attention should be paid to polarity: positive terminal connected to+, negative terminal connected to -, reverse connection will permanently damage the chassis.

2. Module installation

Before installing all SCXI modules, it should be confirmed that the chassis address and voltage have been correctly configured.

Slide the module along the module rail, ensuring that the bottom is aligned with the backplane connector and fully inserted, then secure it to the threaded strip with front panel screws.

Important: The SCXI module does not support hot swapping. Inserting or unplugging modules while the chassis is powered on may cause the backplane fuse to burn out, and even damage the digital bus circuit or the module itself. Be sure to turn off the power of the chassis before operating the module.

3. Installation of filling panel

To protect the interior of the chassis and installed modules, unused slots should be equipped with front panel fillers (with fixing screws) and rear panel fillers (fixed to the rear threaded strip with two screws). Fix from the edge in sequence during installation.

Fan filter maintenance

The rear of the chassis is equipped with a brushless fan for cooling. If the filter is clogged with dust, it will reduce the heat dissipation efficiency, cause the internal temperature to rise, and shorten the life of the chassis and modules. The cleaning steps are as follows:

Turn off the power of the chassis and unplug the power cord.

Place the chassis face down so that the fan is located above (if there are too many cables to flip, operate in place, but be careful to support the fan to prevent wire breakage).

Remove the four screws that secure the fan and filter, and then remove the filter.

Gently rinse the filter with cold tap water until the dust is completely removed, then air dry.

Align the filter with the fan, ensuring that the fan label faces downwards (i.e. towards the inside of the chassis), reinstall the four screws and ensure they are securely fastened.

It is recommended to regularly check the condition of the filter screen, especially in dusty environments where cleaning frequency should be increased.

Electrical specifications and load capacity

The SCXI chassis backplane provides three sets of power supplies: V+(positive analog power supply), V - (negative analog power supply), and+5V (digital logic power supply). Its output capability is as follows:

Power rail voltage range (including ripple) maximum ripple (peak to peak) SCXI-1000/1000DC maximum load SCXI-1001 maximum load

V++18.5 to+25 V 1.5 V 680 mA 2.04 A

V-18.5 to -25 V 1.5 V 680 mA 2.04 A

+5 V+4.75 to+5.25 V 50 mV 250 mA 600 mA

The overall power consumption of the machine is approximately 7 W per slot. According to the maximum load distribution, the current available for each slot is approximately:

V+/V -: 170 mA/slot (4-slot chassis) or 170 mA/slot (12 slot chassis, actual total load is higher, but each slot is still about 170 mA);

+5 V: 50 mA/slot.

When designing your own SCXI module, ensure that the current in each slot does not exceed the above value, and it is best to install an additional 250 mA fuse inside the module to avoid burning out the backplane fuse due to module failure.

Environmental and Safety Certification

Working temperature: 0 ° C to 50 ° C

Storage temperature: -20 ° C to 70 ° C

Humidity: 10% to 90% RH, no condensation

Maximum altitude: 2000 meters

Pollution level: 2 (for indoor use only)

Safety standards:

Meet the requirements of IEC 61010-1, EN 61010-1, UL 1244, and CAN/CSA-C22.2 No. 61010-1.

Electromagnetic compatibility:

Radiation emission: EN 55011 Class A (at 10 meters), FCC Part 15A (above 1 GHz).

Immunity: EN 61326:1997+A2:2001 Table 1.

The use of shielded cables ensures compliance with EMC requirements.

Compliant with the Low Voltage Directive (73/23/EEC) and EMC Directive (89/336/EEC) with CE marking.

Common problems and troubleshooting

1. The chassis cannot be powered on

Check if the power cord is properly plugged in and if the socket has power.

Confirm that the voltage selection knob setting is consistent with the local power grid.

Check if the main power fuse is blown.

For SCXI-1000DC, confirm that the DC input voltage is within the range of 9.5-16 V and the polarity is correct.

2. When the module is plugged in and out while powered on, the chassis shows no response

SCXI module does not support hot swapping. It is possible that the backplane fuse (V+or V -) has been blown or the digital bus is damaged. Replace the backplane fuse first; If the problem persists, please contact NI technical support.

3. All channel readings are the same (even if different voltages are input)