Chapter4 ConnectingSignals
NI6013/6014 User Man ual 4-8 ni.com
Figure4-2. ProgrammableGain Instrumentation Amplifier (PGIA)
InNRSE mode, signals connected to ACH<0..15> are routed to the positive
inputof th e PGIA, and AISENSE is connected to the negativeinput of the
PGIA. In DIFF mode,signals connectedto ACH<0..7> are routed to the
positiveinput of the PGIA, signals connected to ACH<8..15> are routed to
the negativeinput of the PGIA, and AISENSE is not used.
Caution Exceedingthe differentialand common-mode input ranges distorts the input
signals.Exceeding the maximum input voltage rating can damage the device and the
computer.NI is not liable for any damage resulting from such signal connections.
Them aximum input voltage ratings are listed in the Protection column of Table4 -3.
AIGND is an AI common signal that is routed directly to the ground tie
point on the devices.You can use this signal for a general analog ground
tie point to the deviceif necessary.
Note AIGND is not connected to the negativeinput of the PGIA in single-ended mode
unlessit is connected to AISEN SE withan external wire.
The PGIA applies gain and common-mode voltagerej ection and presents
high-inputimpedance to the AI signals connected to the device. Signals are
routed to the positiveand negative inputs of the PGIA through input
multiplexerson the device. The PGIA converts two input signals to a signal
that is the differencebetween the two input signals multipliedby the gain
–
Instrumentation
Amplifier
–
Measured
Voltage
Vm
+
+
PGIA
Vin+
Vin–
Vm=[V
in+–V
in–]*Gain