Rockwell Automation 1763 MicroLogix 1100 Programmable Controllers User Manual - Manual (Page 55)

Publication 1763-UM001D-EN-P - March 2011
Wiring Your Controller 53
Controller I/O Wiring Minimizing Electrical Noise
Because of the variety of applications and environments where controllers are
installed and operating, it is impossible to ensure that all environmental noise
will be removed by input filters. To help reduce the effects of environmental
noise, install the MicroLogix 1100 system in a properly rated (for example,
NEMA) enclosure. Make sure that the MicroLogix 1100 system is properly
grounded.
A system may malfunction due to a change in the operating environment after
a period of time. We recommend periodically checking system operation,
particularly when new machinery or other noise sources are installed near the
MicroLogix 1100 system.
Wiring Your Analog
Channels Analog input circuits can monitor voltage signals and convert them to serial
digital data.
Analog Channel Wiring Guidelines
Consider the following when wiring your analog channels:
• The analog common (COM) is connected to earth ground inside the
module. These terminals are not electrically isolated from the system.
They are connected to chassis ground.
• Analog channels are not isolated from each other.
• Use Belden™ 8761, or equivalent, shielded wire.
• Under normal conditions, the drain wire (shield) should be connected to
the metal mounting panel (earth ground). Keep the shield connection to
earth ground as short as possible.
• To ensure optimum accuracy for voltage type inputs, 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.
IA
COM IV1(+) IV2(+)
Sensor 2
(V) Voltage
Sensor 1
(V) Voltage