National Instruments SCXI Serie Schnellstartanleitung Seite 18

Frequently Asked Questions
My chassis is powered on, and my modules are configured for multiplexed mode, but I am not
getting good data on any channel. What is causing this problem?
The SCXI chassis has backplane fuses, fused at 1.5 A on the SCXI-1000 chassis and at 4 A on the
SCXI-1001 chassis. One or both of the fuses might be blown.
On the SCXI-1600, you can check if the fuses are blown by looking at the power LEDs. Both power
LEDs on the SCXI-1600 and the LED on the chassis must be lit. If any of the LEDs are not lit, one or
both fuses are blown.
On the SCXI-1000, the backplane fuses are located behind the fan. On the SCXI-1001, the backplane
fuses are located behind the right-hand fan, near the power entry module, as viewed from the rear of the
chassis.
Complete the following steps to check or replace fuses.
1. Power off the chassis and remove the power cord.
2. Remove the four screws that secure the fan and filter to the rear of the chassis. When removing the
last screw, be careful to hold the fan to avoid breaking the fan wires.
3. To check whether a fuse is blown, connect an ohmmeter across the leads. If the reading is not
approximately 0 Ω, replace the fuse. The fuse marked with a copper + on the backplane is for the
positive analog supply, and the fuse marked with a copper – is for the negative analog supply.
4. Using long-nose pliers, carefully remove the fuse.
5. Take a new fuse and bend its leads so the component is 12.7 mm (0.5 in.) long—the dimension
between the fuse sockets—and clip the leads to a length of 6.4 mm (0.25 in.).
6. Using long-nose pliers, insert the fuse into the socket holes.
7. Repeat steps 3 through 6, if necessary, for the other fuse.
8. Align the fan and filter with the fan holes, making sure that the label side of the fan is face down.
Reinstall the four screws and make sure the assembly is secure.
Refer to the chassis user manuals for fuse specifications.
My chassis worked until I inadvertently removed and reinserted a module while the chassis was
powered on. Now my chassis does not power on. What can I do?
SCXI modules are not hot-swappable, so you might have blown a chassis fuse. If replacing the fuse does
not correct the problem, you might have damaged the digital bus circuitry or the SCXI module. Contact
NI Technical Support at
MAX does not recognize my chassis when I perform a test. What can I do?
Check the following items:
• Verify the chassis is powered on.
• Verify the chassis is correctly cabled to a DAQ device. If more than one DAQ device is installed in
your PC, verify the device selected for Chassis Communicator is actually connected to the
chassis.
• Check backplane pins to determine if any were bent during installation of the modules.
• Verify correct placement and configuration of the modules. If you did not auto-detect modules,
modules installed in the chassis may not be configured in software. Alternately, modules
configured in software might not match the ones installed in the chassis.
© National Instruments Corporation
for assistance.
ni.com/support
17 SCXI Quick Start Guide