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Chapter 2
SCXI-1300 Terminal Block
The second type of connector available to connect the signals to the SCXI-1100 inputs is the
SCXI-1300 terminal block, which consists of a shielded board with 72 screw terminals to
connect to the SCXI-1100 input connector. Thirty-two pairs of screw terminals are for signal
connection to the 32 differential inputs of the SCXI-1100. One pair of screw terminals connects
to the chassis ground. Three screw terminals connect to the SCXI-1100 OUTPUT and AOREF
pins and to the SCXIbus guard. The remaining three screw terminals are not used. In addition,
solder pads are on each side of the terminal block for circuit additions.
Terminal Block Temperature Sensor
The temperature sensor is located on the SCXI-1300 terminal block. You can connect the
temperature sensor in two ways:
•
Multiplexed Temperature Sensor (MTS) mode–Connect the temperature sensor to the
MTEMP pin (A3) on the front connector and multiplex the sensor at the output multiplexer
along with the PGIA output.
•
Direct Temperature Sensor (DTS) mode–Connect the temperature sensor to a separate data
acquisition channel via MCH1± (pins 5 and 6 on the rear signal connector).
The temperature sensor outputs 10 mV/°C and has an accuracy of ±0.9° C over the 0° to 55° C
temperature range. To determine the temperature, use the following formulas:
(
T(°C) = 100 V
TEMPOUT
[
]
T(°C)
9
T(° F) =
5
where V
is the temperature sensor output and T(°F) and T(°C) are the temperature
TEMPOUT
readings in degrees Fahrenheit and degrees Celsius, respectively.
Terminal Block Jumper Configuration
The SCXI-1100 has two jumpers for configuring the onboard temperature sensor. Jumper W1
(MTEMP) connects the temperature sensor output to the SCXI-1100 output multiplexer. This is
the factory setting. Jumper W2 (DTEMP) connects the temperature sensor to the SCXI-1100
MCH1+ signal on the rear signal connector.
In both MTS and DTS modes, the reference to the temperature sensor signal is the SCXI-1100
analog ground that is connected to MCH0- in the MTS mode and to MCH1- in the DTS mode.
Notice that MCH1- is continuously connected to the SCXI-1100 ground, whereas MCH0- is
switched through the output multiplexer.
One jumper block comprises both jumpers; thus, you can use only one type of configuration at a
time. The parking position for the jumper block is in the MTEMP position. The temperature
sensor is disabled until the RTEMP bit in the Configuration Register selects the sensor.
Table 2-8 shows the SCXI-1300 jumper settings.
© National Instruments Corporation
)
+ 32
2-19
Configuration and Installation
SCXI-1100 User Manual
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