Chapter 2
Connecting Signals
2-6
ni.com
36
SCAN CLK
AI HOLD COMP,
AI HOLD
Input
Scan clock—A rising edge
indicates to the scanned SCXI
module that the E/M Series DAQ
device has taken a sample and
causes the module to advance
channels.
37
SER CLK
EXTROBE*
Input
Serial clock—This signal taps into
the SCXIbus SPI CLK line to clock
the data on the MOSI and MISO
lines.
Table 2-3.
SCXI-1521/B Communication Signals (Continued)
Pin
SCXI Signal
Name
NI-DAQmx
Device Signal
Name
Direction
Description
