Chapter 2 Configuration and Installation
SCXI-1121 User Manual 2-18 www.natinst.com
Front Connector Signal Descriptions
Pin Signal Name Description
A2 CGND Chassis Ground—This pin is tied to the SCXI chassis.
C2 DTEMP Direct Temperature Sensor—This pin connects the
temperature sensor to the MCH4+ when the terminal block
is configured for direct temperature connection.
A4 +5 V +5 VDC Source—This pin is used to power the
temperature sensor on the terminal block. 0.2 mA of source
not protected.
C4 MTEMP Multiplexed Temperature Sensor—This pin connects the
temperature sensor to the output multiplexer.
A6 SCAL Shunt Calibration—This pin is tied to the SCAL bit and is
used to control the SCXI-1321 shunt calibration switch.
CMOS/TTL output not protected.
C6, C8 RSVD Reserved—These pins are reserved. Do not connect any
signal to these pins.
A8, C10, C16,
C22, C28 No Connect Do not connect any signal to these pins.
A10 EGND3 Excitation Ground 3—This pin connects to the excitation
ground 3 via a 51 kΩ resistor.
A12 EX3+ Positive Excitation Output 3—This pin is connected to the
excitation channel 3 positive output.
C12 EX3– Negative Excitation Output 3—This pin is connected to the
excitation channel 3 negative output.
A14 CH3+ Positive Input Channel 3—This pin is connected to the
input channel 3 positive input.
C14 CH3– Negative Input Channel 3—This pin is connected to the
input channel 3 negative input.
A16 EGND2 Excitation Ground 2—This pin connects to the excitation
ground 2 via a 51 kΩ resistor.
A18 EX2+ Positive Excitation Output 2—This pin is connected to the
excitation channel 2 positive output.
C18 EX2– Negative Excitation Output 2—This pin is connected to the
excitation channel 2 negative output.