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Chapter 2
Configuration and Installation
2-12
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Using the Internal Half-Bridge Completion
Your SCXI-1121 includes half-bridge completion for half-bridge and
quarter-bridge setups. The completion network consists of two
4.5 k
Ω
± 0.05% ratio tolerance resistors with a temperature coefficient of
5 ppm/°C. These resistors are connected in series. To enable the network,
you must set two jumpers for each input/excitation channel pair.
When the completion network is enabled, you cannot access the negative
input of the amplifier, which preserves the overvoltage protection of the
channel. Table 2-9 shows how to enable and disable the completion
network.
Note
When using the half-bridge completion network with a quarter-bridge setup, you
must use an extra resistor to complete the bridge. Place this resistor on the terminal block
between the positive input channel and the negative excitation output.
Table 2-9.
Completion Network Jumpers
Channel
Jumpers
Enable Completion
Disable Network
(Factory Setting)
0
W1 and W2
1
W17 and W18
A B
W2
W1
1 2 3
•
•
•
•
•
•
•
A B
W2
W1
1 2 3
•
•
•
•
•
•
•
A B
W18
W17
1 2 3
•
•
•
•
•
•
•
A B
W18
W17
1 2 3
•
•
•
•
•
•
•