Use surge suppressors, Minimizing electrical noise on analog channels – Rockwell Automation 2080-LC20-20QWB_20AWB_20QBB_20QWBR_20AWBR_20QBBR Micro820 20-Point Programmable Controllers User Manual
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12 Micro820 20-Point Programmable Controllers
Publication 2080-IN009B-EN-P - April 2014
2. Gently press the card until it clicks into place.
3. To remove the microSD card from the slot, gently press the card until it clicks back and
releases itself from the slot.
Use Surge Suppressors
Because of the potentially high current surges that occur when switching inductive load devices,
such as motor starters and solenoids, we recommend the use of some type of surge suppression to
protect and extend the operating life of the controllers output contacts. Switching inductive
loads without surge suppression can
significantly reduce the life expectancy of relay contacts. By
adding a suppression device directly across the coil of an inductive device, you prolong the life of
the output or relay contacts. You also reduce the effects of voltage transients and electrical noise
from radiating into adjacent systems.
Refer to the Micro820 Programmable Controllers User Manual, publication
, for
suitable surge suppression methods and recommended surge suppressors.
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 filters.
Several specific steps can be taken to help reduce the effects of environmental noise on analog
signals:
•
Install the Micro800 system in a properly rated (NEMA/IP) enclosure. Make sure that
the Micro800 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, (see
Grounding Your Analog Cable on page
for more information).
•
Route the Belden cable separately from any AC wiring. Additional noise immunity can
be obtained by routing the cables in grounded conduit.
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