Rockwell Automation 1769-OF4 Compact Analog Output Module - Manual (Page 21)

Publication 1769-UM020A-EN-P - December 2009 21
Installation and Wiring Chapter 2
System Wiring Guidelines Consider the following when wiring your system:
•
All module commons (ANLG Com) are connected in the analog
module.
•
The analog common (ANLG Com) is not connected to earth
ground inside the module.
•
Channels are not isolated from each other.
•
For optimum accuracy, limit overall cable impedance by
keeping your cable as short as possible. Locate the I/O system
as close to your sensors or actuators as your application will
permit.
•
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 module end.
(1)
•
Keep shield connection to ground as short as possible.
•
Voltage outputs (Vout 0+…Vout 3+) of the 1769-OF4 module are
referenced to ANLG Com. Load resistance for a voltage output
channel must be equal to or greater than 1 k
Ω
.
•
Current outputs (Iout 0+…Iout 3+) of the 1769-OF4 module
source current that returns to ANLG Com. Load resistance for a
current output channel must remain between 0 and 600
Ω
.
(1) In environments where high-frequency noise may be present, it may be necessary to directly ground cable
shields to earth at the module end and via a 0.01 µF, 2000V capacitor at the sensor end.