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12
Step 4: Installation of the EM3000 System
Noise Suppression
Sentex has designed its products to withstand most inductive voltage spikes without affect. However,
some noise found in power supplies and door strikes, in addition to static discharge, may cause the control
unit to momentarily shut down, lock up, or in extreme cases, become damaged. Unexplained lockups and
intermittent system behavior are common symptoms of static or noise problems. If cycling power will
remedy your problem, carefully follow these instructions:
1. For DC powered door strikes, install a
diode (IN4004 or equivalent) at the
strike with the positive DC power
connected to the cathode (K), or
banded, end of the diode (see Figure 8).
For AC powered door strikes, install an
M.O.V. (metal oxide varistor) rated at 50
volts or higher, or Transorb (P6KE15A
or equivalent) at each door strike. When
installed, they will suppress most
problem door strikes.
2. Properly grounding all readers and hardware, in addition to suppressing noise in the peripheral
equipment, should allow for many years of problem free use.
3. In addition, Sentex requires that a separate power supply (appropriate for the type of
strikes or maglocks used) be installed to power door strikes.
4. Before installing the reader, please read the reader wiring instructions in this manual. Damage
may occur if this is disregarded.
5. Installation must meet all local, state, and federal regulations and codes for electrical installation. If
these codes conflict with the installation methods described in this manual, please call your
service representative.
Doc 6001536, Rev C
Figure 8: Diode for DC Powered Door Strikes
(+)
DC POWER
SOURCE
(-)
1536F5
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