National Instruments SCB-68A User Manual

4-10 | ni.com
Chapter 4 PFI 0 and Digital Input Measurements
Figure 4-13. SCB-68A Circuit Diagram for Digital Input Attenuation
Use positions A and B for PFI 0, and determine the gain according to Equation 4-5:
(4-5)
Digital Input Voltage Dividers
If you use the V
in
voltage of Figure 4-12 to feed TTL signals, you must calculate V
in
so that the
voltage drop on R
2
does not exceed 5 V.
Caution A voltage drop exceeding 5 V on R
2
can damage the internal circuitry of
the DAQ device. NI is not liable for any device damage resulting from improper use
of the SCB-68A and the DAQ device.
45
11
44
SC10
A
+
B
11
+
44
PFI 0
D GND
G
B
BA+()
------------------=

National Instruments SCB-68A Specifications

General

Brand	National Instruments
Model	SCB-68A
Category	Cables and connectors
Language	English