TBX-1329 Installation Guide
6
ni.com
Configuring AC/DC Coupling
Each channel of the TBX-1329 has two switches you can use to switch
from AC to DC; thus, you can configure each channel individually.
The factory-default setting for the switches is the DC position so that the
terminal block passes all signals, DC and AC, to the SCXI module. In the
AC position, the switches switch in a capacitor and, depending on which
module you use, a referencing resistor. This blocks the DC components
of the input signal and provides a true AC signal to the SCXI module.
Each switch is uniquely marked to make switch identification easier.
Each switch that switches the capacitor into the circuit is labeled with SC
X
.
Each switch that switches the resistor into the circuit is labeled with SR
X
.
The
X
symbol represents the channel number; for example, SC2 is the
capacitor switch for channel 2 and SR2 is the resistor switch for channel 2.
Table 2 shows the TBX-1329 terminal block switch settings.
Table 2.
TBX-1329 Terminal Block Switch Settings
Switch Settings for
Each Channel
Description
Switch Configuration
SCXI-1120,
SCXI-1121,
SCXI-1125, and
SCXI-1126
SCXI-1120D
DC coupling selected; removes
capacitor and resistor from the
circuit. Signals go straight
through.
Switch both
SCX
and
SRX
switches
for DC coupling.
Switch both
SCX
and
SRX
switches
for DC coupling.
AC coupling selected;
SCX
connects the capacitor to the
circuit.
SRX
connects the resistor
to the circuit.
Switch both
SCX
and
SRX
switches
for AC coupling.
Switch
ONLY
SCX
switch for
AC coupling.
SRX
must be in the DC
position.
DC
AC
SCX
SRX
DC
AC
SCX
SRX
