National Instruments SCXI-1127 - Manual (Page 52)

Chapter 2 Using the SCXI-1127/1128
© National Instruments Corporation 2-17 SCXI-1127/1128 User Manual
Software Scanning
Unlike hardware scanning, software scanning does not use
hardware-generated triggers. In software scanning, a list of channels kept
by the software is scanned by selecting the desired channel on the
SCXI-1127/1128 and making the required measurement. Refer to the
NI-SWITCH documentation for more information on software scanning.
Making Temperature Measurements
You can use the SCXI-1127/1128 to measure a variety of temperature
devices including thermocouples, RTDs, and thermistors. The following
sections discuss how to use these types of sensors with the
SCXI-1127/1128.
Making Thermocouple Measurements
Figure 2-16 shows a thermocouple (V
1
) connected to channel 3 on the
SCXI-1331 terminal block. The thermocouple is connected in the 2-wire
configuration. Due to the small voltages that thermocouples produce,
National Instruments recommends that you connect them in a 2-wire
(differential) configuration versus a 1-wire configuration.