Data Translation DT9871, Руководство пользователя

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Chapter 4
58
Connecting Current Loop Inputs to RTD Channels
RTD channels on the DT9872 and DT9874 instruments have an input range of ±1.25 V.
Therefore, you can use a 1

shunt resistor to measure ±1.25 A. Similarly, you can use a 0.1

shunt resistor to measure ±12.5 A or a 10

shunt resistor to measure ±0.125 A.
Figure 22 shows how to wire your signals to measure a current loop. In this example, the input
is referenced to ±60 V.
Note: On the standard DT9874 instrument, channels 16 to 31 correspond to the RTD input
channels.
Figure 22: Connecting Current Loop Inputs to RTD Channels
1

shunt resistor
Use a 1

shunt resistor to convert current to voltage: 1

= 1.25 A = 1.25 V.
60 V
+
–
RTD Channel
– Sense +Sense
1 2 4 3
Shield