National Instruments NI 435 Series, User Manual, Page: 41 / 77

Chapter 2 Operating the NI 435x Device
© National Instruments Corporation 2-23 NI 435x User Manual
Figure 2-11. Multiple Transducer Connections to Analog Channels
in One Measurement Setup, Channels 6–9
The NI 435 x analog inputs are protected against damage from voltages
within
±
42 VDC in all ranges when powered on and
±
17 VDC when
powered off.
Caution
Never apply voltages above these levels to the inputs. To prevent possible safety
hazards, the maximum voltage between any of the analog inputs and the computer ground
should never exceed
±
42 VDC when the NI 435 x is powered on and
±
17 VDC when the
NI 435 x is powered off.
Input Ranges
The NI 435 x has six ranges for resistance measurements. These ranges are
25 k
Ω,
50 k
Ω
, 100 k
Ω
, 150 k
Ω
, 300 k
Ω
, and 600 k
Ω
with the 25
µ
A
current source. These ranges correspond to the six input ranges available
for measuring DC voltages developed across resistors. These ranges are
±
625 mV,
±
1.25 V,
±
2.5 V,
±
3.75 V,
±
7.5 V, and
±
15 V. The NI 4351 for
CH7–
Resistance
CH6+
CH6–
RTD
I
EX1+
CH7+
I
EX1–
Ground-Referencing: Off
Open-Thermocouple
Detection: Off
Ground-Referencing: Off
Open-Thermocouple
Detection: Off
R
shunt
(User Supplied)
CH8+
CH8–
Ground-Referencing: On
Open-Thermocouple
Detection: Off
R
shunt
(User Supplied)
CH9+
CH9–
Ground-Referencing: Off
Open-Thermocouple
Detection: Off
Note: I
EX1
is present on the NI 4351 only.
Ground-referenced
current source
0–20 mA
0–40 mA
Floating current source
0–20 mA
0–40 mA
Voltage here is
{–2.5V + [(R
resistance
+ R
rtd
)
×
1 mA]}
Voltage here is
{–2.5V + [R
resistance
×
1 mA]}
Voltage here is –2.5 V