Caution
If you use shielded cabling to connect to a C Series module with a plastic
connector, you must attach the cable shield to the chassis grounding terminal using
1.31 mm
2
(16 AWG) or larger wire. Attach a ring lug to the wire and attach the wire
to the chassis grounding terminal. Solder the other end of the wire to the cable
shield. Use shorter wire for better EMC performance.
For more information about ground connections, visit
and enter the Info Code
emcground
.
Internal Real-Time Clock
The NI 9149 contains an internal real-time clock that maintains system time when the NI 9149
is powered off. The system clock of the NI 9149 is synchronized with the internal real-time
clock at startup. You can set the real-time clock using MAX, or you can set the clock
programmatically using LabVIEW.
Refer to the specifications on
for the real-time clock accuracy specifications.
Battery
The NI 9149 contains a lithium cell battery that stores the system clock information when the
NI 9149 is powered off. There is only a slight drain on the battery when power is applied to
the NI 9149 power connector. The rate at which the battery drains when power is disconnected
depends on the ambient storage temperature. For longer battery life, store the NI 9149 at a
cooler temperature and apply power to the power connector. Refer to the specifications on
for the expected battery lifetime.
The battery is not user-replaceable. If you need to replace the battery, contact NI. Refer to the
specifications on
for information about battery disposal.
Mounting the Device
To obtain the maximum allowable ambient temperature of 70 °C, you must mount the NI 9149
horizontally on a flat, metallic, vertical surface such as a panel or wall. You can mount the
NI 9149 directly to the surface or use the NI Panel Mounting Kit. The following figure shows
the NI 9149 mounted horizontally.
Figure 6.
NI 9149 Horizontal Mounting
1
1. Up
You can also mount the NI 9149 in other orientations, on a nonmetallic surface, on a 35-mm
DIN rail, on a desktop, or in a rack. Mounting the NI 9149 in these or other configurations can
NI 9149 User Manual
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© National Instruments
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