Tunnel Master® wbc Installation Guide
Page 24
Tunnel Master® wbc Installation Guide
Page 24
Common Relay Output Wiring
Common relay output wiring is to be done on the relay board.
CH1
CH2
CH3
CH4
CH5
CH6
CH7
CH8
D
24VAC SOLENOID
SITE SUPPLIED 24VAC
TRANSFORMER
+
-
24VAC SUPPLY
NO
RMA
LL
Y CL
OS
ED
VO
LT
AG
E SU
PP
LY
TE
RM
IN
AL
S
NO
RM
AL
LY
O
PEN
VO
LT
AG
E SU
PP
LY
TE
RM
IN
AL
S
A
B
C
+
-
COMMON RELAY
OUTPUT WIRING
FOUR PRONG
TERMINAL JUMPER
TWO PRONG
TERMINAL JUMPER
On the Relay Board, each relay is referred to as a channel (channels 1 through 24 on each relay board).
Each relay is a single pole - double throw (SPDT). On the terminal strip, each channel has two common
terminals that are shorted to each other (the upper tier common and the lower tier common), a
normally open terminal and normally closed terminal. No voltage is supplied by the relay. A set of dry-
contacts is provided at each channel. External power is required to be run through the dry-contacts of
each relay, ending at the motor starter, solenoid, or device that the relay will be controlling.
If the device to be controlled operates on a 24 V AC, run a wire from the neutral side of the transformer
to the neutral side of the device as shown above (A). Run another wire (B) from the load side of the
transformer to the upper tier common of the relay that is to control the device (channel/relay #1
shown). Run a third wire (C) from the normally open terminal on channel 1 to the load side of the
device controlled by the relay.
In this example, when the controller fires the relay at the programmed time, the circuit between the
common and the normally open terminals will close, thus allowing the electricity to flow through the
relay and activating the load side of the device controlled. Since the neutral is already directly wired to
Figure 18. Common Relay Output Wiring
