Rockwell Automation 1747-ACNR15 ControlNet Adapter Module User Manual - Manual (Page 110)

Publication 1747-UM003A-EN-P
B-18 Understanding Your SLC 500/1746 Control System
Special Considerations
The recommendations given previously provide favorable operating conditions
for most adapter installations. Your application may involve one or more of the
following adverse conditions. Additional measures can be taken to minimize
the effect of these conditions.
Excessive Line Voltage Variations
The best solution for excessive line voltage variation is to correct any feeder
problems in your distribution system. Where this does not solve the line
variation problem, or in certain critical applications, use a constant voltage
transformer. If you require a constant voltage transformer, connect it to the
power supply and all input devices connected to the 1747-ACN15/-ACNR15
chassis.
Connect output devices on the same power line, but their connection along
the power line is normally made before the constant voltage transformer. A
constant voltage transformer must have a sufficient power rating for its load.
Excessive Noise
When you operate the 1747-ACN15/-ACNR15 module in a “noise polluted”
industrial environment, special consideration should be given to possible
electrical interference.
The following reduces the effect of electrical interference:
•
1747-ACN15/-ACNR15 design features
•
proper mounting of adapter within an enclosure
•
proper equipment grounding
•
proper routing of wiring
•
proper suppression added to noise generating devices
Inductive loads, such as relays, solenoids, and motor starters, when operated by
“hard contacts” like push buttons or selector switches, generate surges on the ac
line. Suppression may be necessary when such loads are connected as output
devices or when connected to the same supply line that powers the adapter.
Lack of surge suppression on inductive loads may contribute to faults and
sporadic operation, RAM can be corrupted (lost), and I/O modules may
appear to be faulty or reset themselves.