Chapter 3 ________________________________________________________________ Installation
VAISALA ________________________________________________________________________ 59
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Figure 31 RS-485 Communication Option
Terminate the RS-485 chain with a 120 Ω resistor. This is especially
important with long cables. If the FS11P sensor is at the end of the RS-
485 chain, the 120 Ω resistor can be connected across the screw terminal
pins. The 120 Ω resistor is available in a plastic bag attached to the
power cable inside the interface unit's enclosure.
Figure 32 below illustrates an RS-485 application using a half-duplex
data transfer over a single twisted pair.
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Figure 32 RS-485 Application