Spectrum Controls 1769sc-HART Modules - Manual (Page 26)

Compact IO™ Isolated HART Analog Output Module
User’s Manual 0300217-03 Rev. A
3-8
General
 Power and output wiring must be in accordance with Class 1, Division 2 wiring
methods, Article 501-4(b) of the National Electric Code, NFPA 70, and in
accordance with the authority having jurisdiction.
 Channels are isolated from one another by ±500 Vdc maximum.
 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 120V 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 multiple power supplies are used with analog millivolt inputs, the power supply
commons must be connected.
Terminal Block
 For voltage and current sensors, use Belden 8761 shielded, twisted-pair wire (or
equivalent) to ensure proper operation and high immunity to electrical noise.
 To ensure optimum accuracy, limit overall cable impedance by keeping a cable as
short as possible. Locate the module as close to input devices as the application
permits.
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.
 Keep cable shield connections to ground as short as possible.
 Ground the shield drain wire at one end only. The typical location is as follows.
 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
 To limit the pickup of electrical noise, keep analog signal wires as far as possible
from power and load lines.
 If noise persists for a device, try grounding the opposite end of the cable shield. (You
should only ground one end at a time.)
3.7.2 Terminal Door Label
A removable, write-on label is provided with the module. Remove the label from the
door, mark your unique identification of each terminal with permanent ink, and slide the
label back into the door. Your markings (ID tag) will be visible when the module door is
closed.
3.7.3 Removing and Replacing the Terminal Block
When wiring the module, you do not have to remove the terminal block. If you remove
the terminal block, use the write-on label located on the side of the terminal block to
identify the module location and type.