Analog Input (Ai); Analog Output (Ao) - National Instruments myDAQ User Manual

Protection
Circuit
VBUS
(CSD25302Q2)
Transformer
LDO
Regulator
(TPS71501)
Isolated +3.3 V
Isolated +5 V
Note: NI myDAQ components may be changed or substituted without notice.

Analog Input (AI)

There are two analog input channels on NI myDAQ. These channels can be configured either as
general-purpose high-impedance differential voltage input or audio input. The analog inputs are
multiplexed, meaning a single analog-to-digital converter (ADC) is used to sample both
channels. In general-purpose mode, you can measure up to ±10 V signals. In audio mode, the
two channels represent left and right stereo line level inputs. Analog inputs can be measured at
up to 200 kS/s per channel, so they are useful for waveform acquisition. Analog inputs are used
in the NI ELVISmx Oscilloscope, Dynamic Signal Analyzer, and Bode Analyzer instruments.

Analog Output (AO)

There are two analog output channels on NI myDAQ. These channels can be configured as either
general-purpose voltage output or audio output. Both channels have a dedicated
digital-to-analog converter (DAC), so they can update simultaneously. In general-purpose
mode, you can generate up to ±10 V signals. In audio mode, the two channels represent left and
right stereo outputs.
Caution
that the volume is set to a safe level. Listening to audio signals at a high volume may
result in permanent hearing loss.
4 | ni.com | NI myDAQ User Guide
Figure 2. NI myDAQ Hardware Block Diagram
Regulator +15 V
Current (TPS61170)
Limiter
–15 V
(TPS2553)
+5 V
Regulator
(TPS62003)
+1.2 V
Regulator
(TPS62007)
+3.3 V
USB-STC3
+3.3 V
DC/DC Digital
Isolation Isolator
(ISO7241)
LDO LDO
Regulator Regulator
(TPS76433) (TPS76433)
DMM
HI COM HI
(V Ω
) (A)
f using earphones to listen to the audio output of the NI myDAQ, ensure
8
Gain
(TLE2082)
ADC
(ADS8319)
DAC
(DAC8551)
Switch
(TS12A44514)
Isolation
Barrier
Shift
Register
(SN74AHC595)
Switch
(TS5A3159)
DIO x
Instrumentation
Amplifier
Channel
(OPA1642)
Multiplexer
OP AMP
(OPA1642)
AO 0
OP AMP
AO 1
(OPA1642)
Audio AMP
Line Out R
(TPA6110A2)
Line Out L
AI 0+
AI 0–
AI 1+
AI 1–
Line In R
Line In L