User's Manual

K02021-000 Rev A April 2006
8
2.2 Electrical Installation
2.2.1 Grounding
Connect the reader directly to an earth ground as shown in fugure 4. An earth ground can be established
by driving a copper clad ground rod into the earth. Make certain the DC
resistance between your
established earth ground and the system ground is very low. If direct connection to a ground rod is not
possible, connect the reader to an earth-ground (do not connect to fire sprinkler system), or to steel frames
(building beams) that connect to earth.
Prevent ground loops by connecting the controller ground and the negative line of the power supply to
one common earth ground point. Connecting different points to separate earth grounds may result in a
ground loop. Ground loops may cause poor read range and communication line interference resulting in
no code or improper data transmission to the controller.
In a multiple reader installation, connect all readers to a single earth ground reference point (common
ground).
Figure 4. Grounding the Reader
Note: A multiple reader installation requires a higher maximum current rated power supply. See specifications” on page 2.