Viking Access Systems E-4 - Page 40

VIKING TECHNICAL SUPPORT 1.800.908.0884
38
Relays In General
NOTE:
Viking Access Systems does not provide the external safety devices and access controls.
These items can be purchases from your dealer or distributor.
APPENDIX (A)
In General
In regards to the Viking control board,
all external safety devices and access
controls contain, and are, simple relays
that provide an input to the Viking
control board when the device is
activated.
When these devices are activated,
their internal relays create a contact,
or short, between the “C” and “N.O.”
terminals. This contact is what provides
the command to the Viking control
board.
! TECHNICAL TIP: Viking uses the Normally
Open “N.O.” contact from the device,
excluding “fail-safe” type photo beams.
In such instances, the Normally Closed
“N.C.” will be used instead.
Glossary of Terms
1. Terminal: Wire Connections.
2. Input Terminal: On the Viking control
board, the terminal which is labeled for a
specific command (Re-Open, Exit, Radio,
etc.). The N.O. contact from the access
control device is to be connected to the
Input Terminal.
3. Terminal Block: On the Viking control
board, a removable block containing
multiple terminals.
4. Relay: The component of an access
control or safety device that provides an
input or command to the Viking control
board.
5. “C” Relay Common Terminal: This is
the relay terminal that makes contact
(a short) to the N.O. terminal when the
device is activated. Always wire this relay
terminal to any “GND” terminal at the
control board.
6. “N.O.” Relay Normally Open Terminal:
The relay terminal that has an open
contact to “C” while the relay is not
activated, and a closed contact when the
relay is activated. Almost always wire this
relay terminal to an “Input Terminal” at the
control board,
7. “N.C.” Relay Normally Closed
Terminal: The relay terminal that has a
closed contact to “C” while the relay is not
activated, and an open contact when the
relay is activated. This terminal is rarely
used.
8. Relay Coil: Contains the terminals that
provide power at the relay.
9. “+” Relay Positive Terminal: The
positive power pole for the relay coil.
Always wire this relay terminal to any
“+28V” terminal at the control board.
10. “–” Relay Negative Terminal: The
negative power pole for the relay coil.
Always wire this relay terminal to any
“GND” terminal at the control board.
+
—
COM N.O.
N.C.
EXIT
Not
Used
+28V
GND
GND