© National Instruments Corporation
4-1
SCXI-1124 User Manual
Chapter 4
Theory of Operation
This chapter contains a functional overview of the SCXI-1124 module and explains the operation
of each functional unit of the SCXI-1124.
Functional Overview
The block diagram in Figure 4-1 shows the key functional components of the SCXI-1124.
Optical
Isolation
Rear Signal Connector
SCXIbus Connector
SCXIbus
Interface
Circuitry
Digital Interface
and Control
Calibration
EEPROM
Output
Channel 0
Output
Channel 5
Front Signal Connector
Chassis Ground
Buffer
I
V
Current Sink
Loop Supply
V
OUT
Range
Selection
(1, 5, or 10 V)
Isolated
Ground
Unipolar/
Bipolar
Selection
12-Bit DAC
Chassis Ground
Optical
Isolation
Buffer
I
V
Current Sink
Loop Supply
V
OUT
Range
Selection
(1, 5, or 10 V)
Isolated
Ground
Unipolar/
Bipolar
Selection
12-Bit DAC
+
–
15 - 21 V
+
–
15 - 21 V
Isolation
Barrier
Figure 4-1. SCXI-1124 Block Diagram