National Instruments AT-MIO-64F-5, User Manual

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Chapter 2 Configuration and Installation
© National Instruments Corporation 2-19 AT-MIO-64F-5 User Manual
a 1.2 k
W
resistor. From either AI SENSE pin to the board, there is 1.2 k
W
of resistance.
However, from the AI SENSE signal at pin 19 to the AI SENSE signal at pin 25, there is 2.4 k
W
of resistance.
Pins 3 through 18 of the MIO subconnector are ACH<0..15> signal pins, while the remaining
ACH<16..63> signal pins are located on the extended analog input subconnector. These pins are
tied to the 64 analog input channels of the AT-MIO-64F-5. In single-ended mode, signals
connected to ACH<0..63> are routed to the positive (+) input of the AT-MIO-64F-5 PGIA. In
differential mode, signals connected to ACH<0..7> and ACH<16..39>are routed to the positive
(+) input of the AT-MIO-64F-5 PGIA, and signals connected to ACH<8..15> and ACH<40..63>
are routed to the negative (-) input of the AT-MIO-64F-5 PGIA.
Warning: Exceeding the differential and common-mode input ranges results in distorted input
signals. Exceeding the maximum input voltage rating can result in damage to the
AT-MIO-64F-5 board and to the PC. National Instruments is
not liable for any
damages resulting from such signal connections.
Connection of analog input signals to the AT-MIO-64F-5 depends on the configuration of the
AT-MIO-64F-5 analog input circuitry and the type of input signal source. With the different
AT-MIO-64F-5 configurations, you can use the AT-MIO-64F-5 PGIA in different ways.
Figure 2-6 shows a diagram of the AT-MIO-64F-5 PGIA.
Programmable Gain
+
+
-
-
Vin+
Vin-
V
m
Measured
Voltage
Vm =
[
Gain
Gain = 0.5, 1, 2, 5, 10, 20, 50, 100
GAIN
Vin
+
Vin
-
-
]
*
Figure 2-6. AT-MIO-64F-5 PGIA
The AT-MIO-64F-5 PGIA applies gain and common-mode voltage rejection, and presents high-
input impedance to the analog input signals connected to the AT-MIO-64F-5 board. Signals are
routed to the positive (+) and negative (-) inputs of the PGIA through input multiplexers on the
AT-MIO-64F-5. The PGIA converts two input signals to a signal that is the difference between