National Instruments NI USB-9219 - Manual (Page 12)

NI USB-9219 User Guide and Specifications 12 ni.com
Wiring TEDS Channels
The NI USB-9219 supports only Class II TEDS sensors. Connect the two
TEDS lines to TEDS Data (T+) and TEDS COM (T–) and ensure that
neither T+ nor T– is tied in common to any of the signal inputs (terminals
3 through 6) on the NI USB-9219. Visit
ni.com/info and enter the info
code rdteds for information about TEDS sensors.
Grounding and Shielding Considerations
You can connect ground-referenced or floating signal sources to the
NI USB-9219. If you make a floating connection between the signal source
and the NI USB-9219, make sure the voltages on the positive and negative
connections are within the channel-to-earth working voltage range to
ensure proper operation of the NI USB-9219. Refer to the
Specifications
section for more information about operating voltages and overvoltage
protection.
Note For best signal quality, National Instruments recommends using shielded cables and
twisted-pair wiring whenever possible.
Figures 8 and 9 illustrate connecting grounded and floating signal sources
to the NI USB-9219 in Voltage mode.
Figure 8. Connecting a Grounded Signal Source to the NI USB-9219
Figure 9. Connecting a Floating Signal Source to the NI USB-9219
+
–
Twisted-Pair
Wiring
V
SIG
Signal Source
Shielding
HI
LO
NI USB-9219
+
–
Twisted-Pair
Wiring
V
SIG
V
SIG
Ground
Reference
Signal Source
Shielding
HI
LO
NI USB- 9219