Analog Output Signal Connections - National Instruments AT-MIO-16D User Manual

Chapter 2
For example, for a differential voltage as large as 20 mV and a gain of 500, the largest common
mode voltage that can be rejected is ±7 V. However, if the differential signal is 10 mV with a gain
of 500, ±9.5-V common-mode voltage can be rejected.
The common-mode voltage is measured with respect to the AT-MIO-16D ground and can be
calculated by the following formula:
where V + is the signal at the positive (+) input of the instrumentation amplifier and V -
in
signal at the negative (-) input of the instrumentation amplifier.
If the input signal common-mode range exceeds ±7 V with respect to the AT-MIO-16D ground,
you need to limit the amount of floating that occurs between the signal ground and the
AT-MIO-16D ground.

Analog Output Signal Connections

Pins 20 through 23 of the MIO-16 I/O connector are analog output signal pins.
Pins 20 and 21 are the DAC0 OUT and DAC1 OUT signal pins. DAC0 OUT is the voltage
output signal for analog output channel 0. DAC1 OUT is the voltage output signal for analog
output channel 1.
Pin 22, EXTREF, is the external reference input for both analog output channels. You must
configure each analog output channel individually for external reference selection in order for the
signal applied at the external reference input to be used by that channel. Analog output
configuration instructions are included under the Analog Output Configuration section earlier in
this chapter.
The following ranges and ratings apply to the EXTREF input:
Useful input voltage range:
Absolute maximum ratings:
Pin 23, AO GND, is the ground reference point for both analog output channels and for the
external reference signal.
Figure 2-31 shows how to make analog output connections and the external reference input
connection to the AT-MIO-16D board. If neither channel is configured to use an external
reference signal, do not connect anything to the EXTREF pin.
© National Instruments Corporation
V + + V -
in
V =
cm-actual
2
in
±10 V peak with respect to AO GND
±25 V peak with respect to AO GND
2-33
Configuration and Installation
is the
in
AT-MIO-16D User Manual