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Chapter 2

Function Reference — SCXI_Set_Input_Mode

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Configures the SCXI-1122 channels for two-wire mode or four-wire mode.

inputMode is the channel configuration you want to use.

0:

two-wire mode (module default).

1:

four-wire mode.

When the SCXI-1122 is in two-wire mode (module default setting), the module is configured 
for 16 differential input channels.

When the SCXI-1122 is in four-wire mode, channels 0 through 7 are configured to be 
differential input channels, and channels 8 through 15 are configured to be current excitation 
channels. The SCXI-1122 has a current excitation source that will switch to drive the 
corresponding excitation channel 8 through 15 whenever you select an input channel 0 
through 7. Channel 8 will produce the excitation when you select input channel 0, channel 9 
will produce the excitation when you select input channel 1, and so on. You can use four-wire 
mode for single point data acquisition, or for multiple channel scanning acquisitions. During 
a multiple channel scan, the excitation channels will switch simultaneously with the input 
channels.

You can hook up an RTD or thermistor to your input channel that uses the corresponding 
excitation channel to drive the transducer.

You can call the 

SCXI_Set_Input_Mode

 function to enable four-wire mode at any time 

before you start the acquisition; you can call 

SCXI_Set_Input_Mode

 again after the 

acquisition to return the module to normal two-wire mode.

i16

chassis ID number

i16

module slot number

i16

channel input mode configuration