Chapter 4 Theory of Operation
©
National Instruments Corporation 4-3 SCXI-1161 User Manual
The major components of the SCXI-1161 are as follows:
• The digital interface
• The digital control circuitry
• The relay channels
The SCXI-1161 module is dedicated to switching and controlling power
signal sources. The theory of operation of each of the SCXI-1161
components is explained in the rest of this chapter.
Digital Interface
Figure 4-2 shows a diagram of the SCXI-1161 and SCXIbus digital
interface circuitry.
Figure 4-2. Digital Interface Circuitry Block Diagram
The digital interface circuitry is divided into a data acquisition section
and an SCXIbus section. The SCXI-1161 connects to the SCXIbus via
a 4x24 metral receptacle and to the data acquisition board via a 50-pin
ribbon-cable header. The digital interface circuitry buffers the digital
SCXIbus
Digital Interface
SERDATOUT
SERCLK
SLOT0SEL*
DAQD*/A
SERDATIN
Buffered Serial
Data
Buffered Digital
Signal Controls
Rear Signal Connector
MISO
SPICLK
INTR*
D*/A
MOSI
SS*