Fire-Lite LCD-80FC, Руководство пользователя

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EIA-485 Shield Termination EIA-485 Connections
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Document 53244 Rev. A 03/14/08 P/N 53244:A
Section 5:
EIA-485 Shield Termination
The EIA-485 circuit must be wired using a twisted, shielded pair cable
with a characteristic impedance of 120 ohms (+/- 20%). Do not run
cable adjacent to or in the same conduit as 120 VAC service, noisy elec-
trical circuits that are powering mechanical bells or horns, audio circuits
above 25 V
RMS
, motor control circuits or SCR power circuits.
Note: To ensure static (ESD - electrostatic discharge) protection, all
enclosures, including the LCD-80FC electrical box, must be connected
to earth ground! Never use the EIA-485 shield for this purpose. The
EIA-485 shield is for radiated noise emission protection (RFI, EMI).
Refer to the following figures for details on EIA-485 shield termination.