Spectrum 1762sc-OF8, Руководство пользователя

Страница: 17 / 42

Chapter 2: Installation and Wiring 2-7
User’s Manual Pub. 0300246-01 Rev. C

To ensure optimum accuracy for voltage type outputs, limit overall cable
impedance by keeping all analog cables as short as possible. Locate the
I/O system as close to your voltage type sensors or actuators as possible.

Digital and analog power must be supplied by an Isolated Secondary
Limited Energy Low Voltage source.

Use Belden™ 8761, or equivalent, shielded wire.
WARNING
USE SUPPLY WIRES SUITABLE FOR 20 °C ABOVE
SURROUNDING AMBIENT TEMPERATURE.
WARNING
UTILISER DES FILS D’ALIMENTATION QUI CONVIENNENT A
UNE TEMPERATURE DE 20 °C AU-DESSUS DE LA
TEMPERATURE AMBIANTE.
Grounding

This product is intended to be mounted to a well-grounded mounting
surface such as a metal panel. Additional grounding connections from
the module’s mounting tabs or DIN rail (if used) are not required unless
the mounting surface cannot be grounded.

Under normal conditions, the drain wire (shield) should be connected to
the metal mounting panel (earth ground). Keep shield connection to earth
ground as short as possible.

Ground the shield drain wire at one end only. The typical location is at
the module end.

If it is necessary to connect the shield drain wire at the module end,
connect it to earth ground using a panel or DIN rail mounting screw.

Refer to Industrial Automation Wiring and Grounding Guidelines, Allen-
Bradley publication 1770-4.1, for additional information.
Noise Prevention

Route field wiring away from any other wiring and as far as possible
from sources of electrical noise, such as motors, transformers, contactors,
and ac devices. As a general rule, allow at least 15.2 cm (6 in.) of
separation for every 120 V of power.

Routing field wiring in a grounded conduit can reduce electrical noise.

If field wiring must cross ac or power cables, ensure that they cross at
right angles.

If noise persists for a device, try grounding the opposite end of the cable
shield or ground both ends of the shield.