20
CompactLogix Controller
Rockwell Automation Publication 1769-IN082C-EN-P - February 2013
Analog I/O Wiring Diagrams
•
All analog I/O commons (ANLG COM) are connected in the analog I/O card of the
packaged controller. The analog common (ANLG COM) is not connected to earth
ground inside the packaged controller.
•
Analog I/O channels are not isolated from each other.
•
Use Belden 8761 (or equivalent) shielded wire.
•
Under normal conditions, the drain wire and shield junction must be connected to earth
ground via a panel or DIN rail mounting screw at the analog I/O removable terminal
block end. Keep the shield connection to ground as short as possible.
•
To ensure optimum accuracy, limit overall cable impedance by keeping your cable as
short as possible. Plan to place the packaged controller as close to your sensors or
actuators as your application permits.
(1)
•
If multiple power supplies are used with analog inputs:
•
the power supply commons must be connected.
•
do not exceed the specified isolation voltage.
•
The embedded analog I/O does not provide loop power for analog inputs. Use a power
supply that matches the input transmitter specifications.
•
Differential analog inputs are more immune to noise than single-ended analog inputs.
•
Voltage outputs (Vout 0+ and Vout 1+) of the analog I/O are referenced to ANLG
COM. Load resistance for a voltage output channel must be equal to or greater than 1
K
.
•
Current outputs (Iout 0+ and Iout 1+) of the analog I/O source current that returns to
ANLG COM. Load resistance for a current output channel must remain between
0…300
.
•
Voltages on Vin+, V/Iin-, and Iin+ of the analog I/O must be within 0 to +10V DC of
analog common.
ATTENTION:
Analog outputs may fluctuate for less than a second when power is applied or
removed. This characteristic is common to most analog outputs. While the majority of loads will
not recognize the short signal, take preventive measures to ensure that connected equipment is
not affected.
IMPORTANT
In environments where high-frequency noise may be present, it may be necessary to directly
ground cable shields to earth at the removable terminal block end and via a 0.1μF capacitor at
the sensor end.
(1)
Cable length over 50 m (164.04 ft) may impact accuracy. For details, refer to the Compact Combination Analog I/O Module, publication
1769-UM008
.
