Detcon 812B-FB - Manual (Page 3)

1.2 S
PECIFICATIONS
Electrical Classification
NEMA 4X
Dimensions
15.75''W x 18''H x 9.75''D
Capacity
8 single channels
Power Input
117VAC/24VDC
P Po ow weerr C Co on nssu um mp pttiio on n
5 watts per channel (full alarm peak load)
O Ou uttp pu uttss
Discrete Analog 4-20 mA DC
Serial RS-485 Modbus™
Discrete or zoned alarm relays
Contacts include common with jumper selectable choice (on controller) of normally-open or normally-closed for four alarms
Resistive load: 5A, 250 VAC; 5A, 30 VDC
Inductive load: 2A, 250 VAC; 2A, 30 VDC
Max. operating current: 5A
O Op peerra attiin ngg T Teem mp peerra attu urree R Ra an nggee
-40°F to +175°F
W Wa arrrra an nttyy
One year
1.3 M ULTIPLE A LARM R ELAY C IRCUIT
A multiple alarm relay circuit (referred to in further text as MARC) mounted on the controller mother board is
provided with each Detcon Model 812B-FB. The MARC (figure 1) consists of 4 interposing relays (contacts are
rated 10 amp @ 120 VAC/8 amp @ 30 VDC) with 24VDC coils as standard. Other coil voltage ratings must be
specified at time of order. The MARC can be configured to output Form C dry contacts (common, normally open
and normally closed), AC power or DC power. A 5 amp microfuse is provided for each relay and is configured in
series with the common pole of its respective relay. This configuration is functional regardless of whether Form C
dry contacts, AC power or DC power outputs are used.
An in/out termination is provided for applying AC or DC power into any one of the interposing relays. A gold
plated jumper tab is used to apply the in/out power option to its corresponding relay, thus the 4 relays may be
used in a combination of Form C dry contacts and DC outputs or Form C contacts and AC outputs.
The terminations labeled “Alarm Coil Power” located on the left of the 812B-FB motherboard are used only for coil
power. The “+” termination may be used to provide for various relay logic through the Form C dry contacts termi-
nals of each individual Model 12B channel located on the 812B-FB motherboard. The “–” termination should be
wired into the common terminal (shown by a common symbol) located on the left of the MARC.
The terminations labeled “Alarm Power” located on the left of the 812B-FB motherboard are used for providing
power to the In/Out termination on the MARC. As can be seen in the 812B-FB schematic/wiring diagram (figure
2), the alarm power terminations for AC come directly from the AC input terminals located above on the 812B-FB
motherboard. The same is true of the DC power terminations.
N No ottee:: DC power used to drive alarms must be obtained through a remote DC power source. The remote DC
power source should be terminated to the terminals labeled “DC IN” located on the 812B-FB motherboard. The
“DC IN” terminations function as both an alternative DC source used to power the 812B-FB as well as provide
power for DC alarms. The 812B-FB power supply is not capable of providing power for alarm devices.
Mounting hardware is pre-installed on the 812B-FB motherboard for an additional multiple alarm relay circuit. See
section 1.9 for part number and ordering information.
Model 812B-FB NEMA 4 Control Enclosure PG.3