Detcon 812B-FB User Manual

detcon inc.

Detcon

Model 812B-FB

NEMA 4 Control Enclosure

Operator’s Installation & Instruction Manual

January 1, 1999 Document #2130 Rev. 1.0

FUSE

PRESS

ALARM 3

ALARM 2

ALARM 1

FAULT

ALARM
RESET/

Test

HOUSTON, TEXAS

detcon inc .

able

disable

ALARM

MODEL 12B

HYDROGEN

SULFIDE

MONITOR
ppm H2S

ALARM 3

ALARM 2

ALARM 1

FAULT

ALARM
RESET/

Test

HOUSTON, TEXAS

detcon inc .

able

disable

ALARM

MODEL 12B

HYDROGEN

SULFIDE

MONITOR
ppm H2S

ALARM 3

ALARM 2

ALARM 1

FAULT

ALARM
RESET/

Test

HOUSTON, TEXAS

detcon inc .

able

disable

ALARM

MODEL 12B

HYDROGEN

SULFIDE

MONITOR
ppm H2S

ALARM 3

ALARM 2

ALARM 1

FAULT

ALARM
RESET/

Test

HOUSTON, TEXAS

detcon inc .

able

disable

ALARM

MODEL 12B

HYDROGEN

SULFIDE

MONITOR
ppm H2S

ALARM 3

ALARM 2

ALARM 1

FAULT

ALARM
RESET/

Test

HOUSTON, TEXAS

detcon inc .

able

disable

ALARM

MODEL 12B

HYDROGEN

SULFIDE

MONITOR
ppm H2S

ALARM 3

ALARM 2

ALARM 1

FAULT

ALARM
RESET/

Test

HOUSTON, TEXAS

detcon inc .

able

disable

ALARM

MODEL 12B

HYDROGEN

SULFIDE

MONITOR
ppm H2S

ALARM 3

ALARM 2

ALARM 1

FAULT

ALARM
RESET/

Test

HOUSTON, TEXAS

detcon inc .

able

disable

ALARM

MODEL 12B

HYDROGEN

SULFIDE

MONITOR
ppm H2S

ALARM 3

ALARM 2

ALARM 1

FAULT

ALARM
RESET/

Test

HOUSTON, TEXAS

detcon inc .

able

disable

ALARM

MODEL 12B

HYDROGEN

SULFIDE

MONITOR
ppm H2S

POWER

ON/OFF

FUSE

2 AMP

ALARM

DISABLE

HOUSTON, TEXAS

detcon inc.

Model

812B-FB

Table of Contents

1.0 Introduction

1.1 Description

1.2 Specifications

1.3 Multiple Alarm Relay Circuit

1.4 Alarm Disable

1.5 Remote Alarm Reset

1.6 Installation

1.7 Start-up

1.8 Maintenance & Repair

1.9 Spare Parts List

1.10 Warranty

1.0 INTRODUCTION

Detcon Model 812B-FB consists of 3 major assemblies:

1. The NEMA 4 fiberglass control enclosure.

2. The Model 12B single channel digital control modules.

3. The remote mount gas sensor assemblies.

The NEMA 4 control enclosure is detailed in section 1.0 of the manual, the control modules in section 2.0, and
applicable sensor assemblies in section 3.0.

1.1 D

ESCRIPTION

Detcon Model 812B-FB control enclosure, along with Model 12B digital control modules, is designed to serve as a
host assembly for up to eight remote mount gas detection sensor assemblies. The control enclosure is rated NEMA
4X, which is by definition rain tight, and therefore suitable for outdoor location in electrically non-hazardous envi­ronments.

The single channel modular design supports application f lexibility wherein multiple function gas detection systems
can be configured in any combination up to eight channels. All control modules are plug-in front panel accessible
for easy maintenance and repair. The system is powered by VAC line power and/or 24VDC unless otherwise speci­fied at time of order.

The control enclosure includes, as standard operating controls; a power on/off switch, an alarm disable switch and
a line power fuse. Discrete output terminal strips located on the controller motherboard are provided for sensor ter­minations, Form C dry contact alarm outputs for three alarms plus fault (common and choice of normally open or
normally closed), 4-20 mA outputs for remote recording devices, and RS-485 serial Modbus™ output. Terminations
are provided for VAC power in, VDC power in, and remote alarm reset. A multiple alarm relay circuit card is also
provided along with its respective logic and power terminations.

The Form C relay outputs, may be discrete, zoned, or common by gold plated jumper tabs located on the con­troller mother board.

Model 812B-FB NEMA 4 Control Enclosure PG.2

1.2 SPECIFICATIONS

Electrical Classification

NEMA 4X

Dimensions

15.75''W x 18''H x 9.75''D

Capacity

8 single channels

Power Input

117VAC/24VDC

PPoowweerr CCoonnssuummppttiioonn

5 watts per channel (full alarm peak load)

OOuuttppuuttss

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

OOppeerraattiinngg TTeemmppeerraattuurree RRaannggee

-40°F to +175°F

WWaarrrraannttyy

One year

1.3 MULTIPLE ALARM RELAY CIRCUIT

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 termi­nals 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.

NNoottee::

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

Model 812B-FB NEMA 4 Control Enclosure PG.4

Multiple Alarm Relay Circuit

812B-FB

J1 J2 J3 J4

F1 F2 F3 F4

4

3

2

1

I/O

C

NC

NO

4

C

NC

NO

3

C

NC

NO

2

C
NC 1

NO

Coil #4

Coil #3

Coil #2

Coil #1

Common

#4

#3

#2

#1

#4 #3 #2 #1

In/Out

Com

NC

NO

Com

NC

NO

Com

NC

NO

Com

NC

NO

#4

#3

#2

#1

I/O Jumpers

5 Amp Micro Fuse

Figure 1

Model 812B-FB NEMA 4 Control Enclosure PG.5

Figure 2

RED

BLK

GND

A (+)

B (–)

Shld

PS VDC

Alm Reset

VDC IN

VAC IN

L1

N

RS-485

Alm Pwr

P1

6A 50V

D1

P6

P7

P8

P9

16ga x 6"

16ga x 6"

D2 6A 50V

TB2

Pin 7 + Pin 2 N

Pin 6 Com

TAN 22ga x 9"

TAN 22ga x 9"

BLK 16ga x 9"

BLK 16ga x 9"

Pwr Sw

Power Supply

BLK 16ga x 9"

RED 16ga x 9"

RED 16ga x 9"

P2 P3 P4

BLK 16ga x 9"

Fuse

Alm Dis Sw

V18
U17
T16
S15
R14
P13
N12
M11
L10
K9
J8
H7
F6
E5
D4
C3
B2
A1

Pin 3 L

Pin 1

TAN 22ga x 9"

TAN 22ga x 9"

BLK 16ga x 9"

BLK 16ga x 9"

Typ. x 8
Controller Connector

TB1

RED 16ga x 9"

RED 16ga x 9"

16ga x 6"

16ga x 6"

16ga x 6"

PS VAC

L1 - BLK

N - WHT

GND - GRN

P5

VDCVAC

L1

N

GND

Alm Coil Pwr

VDC

P10

P11

Typ. x 8

Sensor

CH1 CH2

mA

Com

NO/NC

Alm 3

Com

NO/NC

Alm 2

Com

Alm 1

NO/NC

Com

Fault

NO/NC

Out

4-20mA

Typical

Jumpers

x 7

1.4 ALARM DISABLE

The alarm disable switch, located on the front panel (figure 3), operates by removing DC common from the
“Alarm Coil Power” terminals. Disabling of alarms does not inhibit any function of the Model 12B digital control
modules. The digital display, alarm LEDs and on board alarm relays remain active.

1.5 R

EMOTE ALARM

RESET

A remote mounted normally open momentary switch may be used to reset the alarms of all Model 12B controllers
(figure 4). The reset function is effective when the Model 12B’s respective alarms have been programmed in the
latching position and alarm conditions have passed. Each Model 12B controller has its own alarm reset switch
which is discussed further in section 2.0.

Model 812B-FB NEMA 4 Control Enclosure PG.6

Figure 3

Figure 4

POWER

ON/OFF

812B-FB

FUSE

2 AMP

FUSE

PRESS

ALARM

DISABLE

Alm Reset

812B-FB

1.6 INSTALLATION

1. Securely mount the 812B-FB enclosure in accordance with the drawing in figure 5.

NNoottee::

Reference figure 6 for wiring terminations.

CCaauuttiioonn::

Observe correct polarity when terminating all input/output field wiring. Failure to do so may result in

circuit damage on power up.

2. Connect 117VAC input to the terminal strip labeled “VAC IN” (L1, N, GND).

3. If applicable, connect a 24VDC source or standby battery to the terminal strip labeled “VDC IN” (+ and –).

4. Refer to installation and wiring detail of remote mount sensor assemblies as detailed in section 3.0. Terminate

field wiring from sensors to the 812B-FB motherboard. Terminals are labeled “Sensor” (mA, + and –).

5. If applicable, terminate the discrete 4-20 mA outputs to external device(s). Terminals are labeled “4-20mA Out”

(+ and –).

6. If applicable, terminate the RS-485 serial output to external device(s). Terminals are labeled “RS-485” (A+, B–,

and Shield).

7. Based on the application and use of relay contact outputs, complete all wiring terminations prior to application

of power. Shut-in controls may be omitted until system test is complete. Terminals are labeled “ALARM 1”
(Com & NO/NC), “ALARM 2” (Com & NO/NC), “ALARM 3” (Com & NO/NC), and “Fault” (Com &
NO/NC). Relay contact outputs may be discrete or zoned via the gold-plated jumper tabs. Relay contact outputs
may be used in conjunction with the multiple alarm relay circuit as described in section 1.3.

Model 812B-FB NEMA 4 Control Enclosure PG.7

Figure 5

20.75

Mounting Holes - 7/16" Dia.

19.25

12.5

15.75

9.75

8. If applicable, connect a normally open momentary remote mounted switch to the terminal strip labeled “Alarm Reset”.

1.7 S

TART U

P

Upon completion of all field wiring: Depress the power switch located on the front panel. Note that each Model
12B controller digital display illuminates. Varying readings may occur during sensor warm-up. A 10 second alarm
delay will occur on power up. Refer to section 3.0 for additional sensor start-up detail.

1.8 MAINTENANCE & REPAIR

The Detcon Model 812B-FB’s modular design allows for minimum down time during maintenance and/or repair.
The model 12B control modules may be changed by simply loosening its mounting screw and sliding the module
out of its card cage. See section 3.0 for more information on the 12B control module.

Replacement of the power switch, fuse holder, or alarm disable switch is accomplished by: removing the 10 screws
that secure the 812B-FB face plate; disconnecting the three plugs from their respective headers; remove the wires
from the plug of the component to be replaced; snap the component out of the 812B-FB face plate and then
reassembly with the new component. Reference figure 2 for wiring details.

Replacement of the power supply is accomplished by: removing the 10 screws that secure the 1212F-FB face plate;
disconnecting the three plugs from their respective headers; disconnect the two power supply plugs from their
respective headers; remove the three screws that hold the power supply bracket the PCB motherboard; remove the
four screws that hold the power supply bracket to the power supply; disconnect the wires from the power supply
and then reassembly with the new power supply. Reference figure 2 for wiring details.

Model 812B-FB NEMA 4 Control Enclosure PG.8

Figure 6

Alm Reset

VDC IN

VAC IN

L1

N

GND

RS-485

A (+)

B (–)

Shld

Alm Pwr

VDCVAC

L1

N

GND

Alm Coil Pwr

Sensor

mA

Com

NO/NC

Alm 3

Com

NO/NC

Alm 2

Com

Alm 1

NO/NC

Com

Fault

NO/NC

Out

4-20mA

Zone Programming Jumpers

CH1 CH2 CH8

VDC

1.9 SPARE PARTS LIST

Part # Description
5026 Multiple alarm relay circuit
0295 5 amp micro fuse
3618-MAP-24 130 watt, 24 VDC switcher power supply
0224 Gold plated jumper tab
2812 24 VDC lamp for power and alarm disable switch
0298 2 amp 3AG slow blow fuse
320-3217-1 Power switch assembly
320-3217-2 Alarm Disable switch assembly
2806 Green switch cap (for power switch)
2807 Red switch cap (for alarm disable switch)
3280 Fuse holder

1.10 WARRANTY

Detcon Inc., as manufacturer, warrants under intended normal use each new Model 812B-FB NEMA 4X control
enclosure to be free from defects in material and workmanship for a period of one year. The warranty period begins
from the date of shipment to the original purchaser and ends one year thereafter. All warranties and service policies
are FOB the Detcon Inc. facility located in The Woodlands, Texas.

Model 812B-FB NEMA 4 Control Enclosure PG.9

Shipping Address: 3200 A-1 Research Forest Dr., The Woodlands, Texas 7381

Mailing Address: P.O. Box 8067, The Woodlands, Texas 77387-8067

phone [phone] • fax [phone] • www.detcon.com • [e-mail]