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TBX-1303 32-Channel Isothermal Terminal Block
14
ni.com
Use long-nose pliers to remove or replace the resistor networks in the
sockets; be careful not to damage the network package. Make sure pin 1 of
each network is in the correct socket. Refer to Figures 4 and 7 for correct
network placement.
Each network is labeled with descriptive numbers on the left front side,
and pin 1 is located directly beneath the black dot within these numbers.
The 10
Ω
resistor network is labeled
10x-1-100
(10
×
10
0
Ω
); the 10 M
Ω
resistor network is labeled
10x-1-106
(10
×
10
6
Ω
). Figure 7 shows
examples of these resistor networks.
Figure 7.
Resistor Networks
SCXI-1100 Module
For the open thermocouple channel to saturate without disturbing the
measurements on any other channel, use an interchannel delay of 200 µs
at a gain of 100 or higher, which corresponds to a sample rate of 5 kHz.
After installing the 10
Ω
bias resistors, you can accurately measure at the
maximum sampling rate of the module. The open thermocouple channel
may not saturate if the interchannel delay is less than 200 µs or if the sample
rate is more than 5 kHz at a gain of 100 or higher.
If you want fast open thermocouple detection and you have short
thermocouple leads, or if high accuracy is not important, you can replace
the pull-up resistors with a lower value resistor network. For example,
you can replace the pull-up resistor with a 1 M
Ω,
10-pin bused
configuration resistor network (not included) and have a sample rate of
20 kHz (interchannel delay of 50 µs typical).
With a 10
Ω
bias resistor
network, the current leakage would be 5 µA (5 V
÷
1 M
Ω
), which can
result in a larger offset error because of thermocouple lead resistance.
Use long-nose pliers to remove or replace the resistor networks in the
sockets; be careful not to damage the network package. Make sure that
pin 1 of each network is in the correct socket. Refer to Figures 4 and 7
for correct network placement.
Mfr. code
10x-1-100
Pin 1
Mfr. code
10x-1-106
Pin 1
a. 10
Ω
Resistor Network
b. 10 M
Ω
Resistor Network