Chapter 2 Using the SCXI-1127/1128
© National Instruments Corporation 2-11 SCXI-1127/1128 User Manual
Figure 2-10. Mixed Mode Scanning with an SCXI-1331
You can scan the channels in any sequence you want. You can connect more
than one SCXI-1127/1128 module together using the HVAB-backplane
adapter from the SCXI-1357/1358 kits to expand the channel count of the
system.
When combining different modes in one module it is important to use the
channels efficiently. Generally you should connect the 4-wire channels
first, followed by the 2-wire channels, and finally by the 1-wire channels.
Hardware-Timed and Software Scanning
The SCXI-1127/1128 provides a very flexible scanning architecture. You
can scan the channels randomly and can have multiple input modes in the
same scan. This is useful for connecting multiple sensor types to one
module.
There are two basic methods of scanning—hardware-timed scanning
and software scanning. In hardware-timed scanning, the measurement
instrument, such as a DMM, communicates via digital trigger signals to the
SCXI-1127
R1
V1
V2
–
–
+
+
–
+
Iex
1-Wire
Connection
2-Wire
Connection
4-Wire
Connection