Minimizing electrical noise on analog channels – Rockwell Automation 1763 MicroLogix 1100 Programmable Controllers User Manual User Manual
Page 56

Publication 1763-UM001D-EN-P - March 2011
54 Wiring Your Controller
•
The controller does not provide loop power for analog inputs. Use a
power supply that matches the transmitter specifications as shown
below.
Minimizing Electrical Noise on Analog Channels
Inputs on analog channels employ digital high-frequency filters that
significantly reduce the effects of electrical noise on input signals. However,
because of the variety of applications and environments where analog
controllers are installed and operated, it is impossible to ensure that all
environmental noise will be removed by the input filters.
Several specific steps can be taken to help reduce the effects of environmental
noise on analog signals:
•
install the MicroLogix 1100 system in a properly rated (i.e., NEMA)
enclosure. Make sure that the MicroLogix 1100 system is properly
grounded.
•
use Belden cable #8761 for wiring the analog channels, making sure that
the drain wire and foil shield are properly earth grounded.
•
route the Belden cable separately from any AC wiring. Additional noise
immunity can be obtained by routing the cables in grounded conduit.
IV1(+) or IV2(+)
IA COM
IV1(+) or IV2(+)
IA COM
+
-
+
-
+
-
IV1(+) or IV2(+)
IA COM
+
-
+
-
GND
+
-
Transmitter
Transmitter
Transmitter
Supply
Signal
Supply
Signal
Controller
Controller
Controller
Power
Supply
3-Wire Transmitter
4-Wire Transmitter
2-Wire Transmitter
Power
Supply
Power
Supply