Rockwell Automation 1766-Lxxxx MicroLogix 1400 Programmable Controllers User Manual - Manual (Page 55)

Rockwell Automation Publication 1766-UM001H-EN-P - May 2014 41
Wire Your Controller Chapter 3
Figure 14 - Analog Input Transmitter Specifications
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 1400 system in a properly rated enclosure, for
example, NEMA. Make sure that the MicroLogix 1400 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.
IV0(+), IV1(+), IV2(+) or IV3(+)
Controller
IV0(+), IV1(+), IV2(+) or IV3(+)
Controller
+ -
+
- +
-
IV0(+), IV1(+), IV2(+) or IV3(+)
COM ANA
Controller
+
-
+
-
GND
+
-
COM ANA
COM ANA
2-Wire Transmitter
3-Wire Transmitter
4-Wire Transmitter
Transmitter
Transmitter
Transmitter
Supply Signal
Supply Signal
Power
Supply
Power
Supply
44530