Chapter4 SignalConnections
6023E/6024E/6025EUser Manual 4-10 ni.com
Figure4-3. ProgrammableGain Instrumentation Amplifier (PGIA)
Insingle-ended mode (RSE and NRSE), signals connected to ACH<0..15>
are routed to the positiveinput of the PGIA. In DIFF mode, signals
connected to ACH<0..7>are routed to the positive input of the PGIA, and
signals connected to ACH<8..15>are routed to the negative input of the
PGIA.
Caution Exceedingthe DIFF and common-mode input range sd istorts your input signals.
Exceeding themaximum input voltage rating can damage the device and the computer.
NationalInstruments is not liable for any damages resulting from such signal connections.
Them aximum input voltage ratings are listed in the Protection column of Table4 -3.
In NRSE mode, the AISENSE signal connects internally to the negative
inputof the PGIA when their corresponding channels are selected. In DIFF
and RSE modes, AISENSE is left unconnected.
AIGNDis an analog input common signal that routes directly to the ground
connectionpoint on the devices. Youcan use this si gnal for a general analog
ground connection point to your deviceif necessary.
The PGIA applies gain and common-mode voltagerej ection and presents
highinput impedance to the analog input signals connected to yo urdevice.
Signals are routed to the positiveand negative inputs of the PGIA through
inputmultiplexers on the device. The PGIA converts two input signals to a
signalthat is the difference between the two input signals multiplied by the
-
Programmable
Gain
Instrumentation
Amplifier
-
Measured
Voltage
Vm
+
+
PGIA
Vin+
Vin-
Vm=[V
in+-V
in-]*Gain