Chapter 5 Adding Components forSpecial Functions
SCB-68 Shielded Connector Block User Manual 5-22 ni.com
Analog Output and Digital Input Attenuators
To build a two-resistor circuit for attenuating voltages at the DAC0OUT,
DAC1OUT, and TRIG1 pins on the SCB-68, refer to the pad positions in
Figure 5-22.
Figure 5-22. SCB-68 Circuit Diagram for Digital Input Attenuation
Use positions R1 and RC1 for TRIG1, and determine the gain according to
Equation 5-17:
(5-17)
Use positions R2 and RC2 for DAC1OUT, and determine the gain
according to Equation 5-18:
(5-18)
Use positions R3 and RC3 for DAC0OUT, and determine the gain
according to Equation 5-19:
(5-19)
Special Considerations for Analog Input
When calculating the values for R1 and R2, consider the input impedance
value from the point of view of Vin, as Figure5-23 sho ws.
CF
RE
Vin Vm
ACH<
i
>
ACH<
i
+8>
+
+
GRC1
RC1R1+()
-----------------------------=
GRC2
RC2R2+()
-----------------------------=
GRC3
RC3R3+()
-----------------------------=