Rockwell-automation 1771-IR , D17716.5.76 RTD INPUT MODULE Manual de usuario descargar pdf (Pagina 61)

2 and 4-Wire Sensors

Appendix E

E2

Figure E.2

Connections

for 3 and 4-W

ire Sensors

3-Wire Sensor

Leave Open

4-Wire Sensor

There are several ways to insure that the lead resistance values match as closely

as possible. They are:

use heavy gauge wire (16–18 gauge)

keep lead distances less than 1000 feet

use quality cable that has a small tolerance impedance rating.

Figure E.3 shows how to connect 4–wire sensors to the field wiring arm of the

RTD Input module. A 4–wire sensor has two pairs of leads; one pair for each

resistor junction. One wire of the 4 is not used (it does not matter which one).

This leaves 3 wires – one pair and one single wire. You must connect the single

wire to the terminal marked ”A”. You connect the remaining pair of wires to

terminals ”B” and ”C”. It doesn’t matter which wire of the pair connects to

terminal ”B” and which wire connects to terminal ”C” so long as all 3 wires are

the same AWG gauge.

Connecting 4-Wire Sensors

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Rockwell-automation 1771-IR , D17716.5.76 RTD INPUT MODULE Manual de usuario Pagina 61