SCC-68 User Guide
20
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Figure 14 shows the power supply path and power distribution of the
SCC-68.
Figure 14.
SCC-68 Power Distribution Block Diagram
LED
The LED in the SCC-68 shows the status of the power supply. The SCC-68
monitors the voltage of the +5V signal from the DAQ device, as shown in
Figure 14. Table 2 shows the correlation between power levels in the
SCC-68 and the LED status.
Table 2.
SCC-68 Power Levels
Voltage on +5V Signal
LED Status
Meaning
≥
4.5 V
*
On
Power on
≥
2 V and <4.5 V
*
Blinking
Power insufficient
†
<2 V
Off
Power is off or power
insufficient
*
Due to component variations, the threshold for the LED can vary between 4.25 V
and 4.5 V.
†
Refer to the
Power Supply Considerations
section for more information about supported
SCC module configurations and other SCC-68 power supply issues.
SCC
Mod 1
+15V
+5V Screw
Terminal
(Pin 8)
SCC-68
LED
Voltage
Monitor
Switching
Power Supply –15V
+5V (Filtered)
SCC
Mod 2
SCC
Mod 3
SCC
Mod 4
Current
Limiter
PC or PXI
Chassis
Power
Supply
DAQ Device
+5V
GND
Filter
External
Power Supply
GND
GND
+5V
SW1
