Data Translation DT300 Series, Руководство по началу работы

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Attaching and Configuring a Screw Terminal Panel/ Backplane
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Configuring Resistors on the STP300
Locations are provided on the STP300 screw terminal panel for
installing bias return and current shunt resistors. The following
subsections describe how to configure these resistors.
Configuring Resistors R1 to R8 - Bias Return
Resistor locations R1 to R8 connect the low side of analog input
channels to analog ground. These resistor locations are typically used
when connecting differential inputs to analog input channels 0 to 7,
where R1 corresponds to analog input channel 0 and R8 corresponds
to analog input channel 7.
The high side of the corresponding analog input channel returns the
source input impedance through the bias return resistors to the low
side of the channels, then to analog ground. Typical resistor values
are 1 k
Ω
to 100 k
Ω
depending on the application. Refer to Figure 9 on
page 49 for an example of using bias return resistors with differential
inputs.
Configuring Resistors R9 to R16 - Current Shunt
Resistor locations R9 to R16 are typically used to convert current to
voltage on channels 0 to 7, where R9 corresponds to analog input
channel 0 and R16 corresponds to analog input channel 7.
The resistor location connects the high side of the channel to the low
side of the corresponding channel, thereby acting as a shunt. If, for
example, you add a 250
Ω
resistor to location R9, then connect a 4 to
20 mA current loop input to channel 0, the input range is converted to
1 to 5 V. Note that, depending on your application, you may need to
use resistors R1 to R8 with resistors R9 to R16 for proper operation.
Refer to
Figure 11 on page 51 for an example of using current shunt
resistors with current loop inputs.