Scott QuadScan II 7400 Operation & Maintenance Manual
Warning: Read & understand
QuadScan II
MODEL 7400
Four Channel Receiver and Controller
Operation & Maintenance Manual
Rev: 7400 Rev F
Date: 5/02/08
ECN 129028
Part Number: 087-0023
contents of this manual prior to
opera
result in serious injury or death.
tion. Failure to do so could
TABLE OF CONTENTS
I
NTRODUCTION
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1
Important Safety Issues & Warnings
Unpacking
G
eneral Description
Figure 1 - Model 7400 QUAD-SCAN II Complete Assembly
QUICK START
Quick Start Programming Menu Tree
RECEIVER/CONTROLLER
General
NEMA-4X Wall Mounted Enclosure
Figure 2- Model 7400 QuadScanII
Figure 2A – Enclosure Side View
Display/Function Assembly
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1
1
2
3
4
5
8
8
9
9
9
Figure 3 - Model 7400 Front Panel Push Buttons
CPU/Power Supply Boards
Figure 4 - Terminal Strip Layout
INSTALLATION
Selecting the Physical Location
Methods of Physical Mounting
Figure 5 - Mounting Dimensio
Directions for Wiring
Figure 6 - Terminal Block Arrangement on Main I/O – Power Supply Board
Figure 7 – Transmitter Wiring to Model 7400
Figure 8 - Wiring of Normally Open Field Contact into Model 7400
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ns of Model 7400
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Table of Contents
1
SYSTE
Figure 9 - Battery Backup (P/N 096-0719)
Outline & Interconnection Wiring
M OPERATION
General
Display Readings
Visual Indications
Current Loops
Current Loop Outputs
Alarm and Re
Figure 10 - Alarm Set For Increasing or Decreasing Gas Concentrations
Latching Alarms
Energized Relays (Fail Safe)
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(LEDs)
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lay Operation
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Common Alarm Relays
Fail Relay
Horn and Horn Relay
Inhibiting Alarms
Sensor Damping Constant
Zero DB
SETUP AND PROGRAMMING.....................................................................................................28
Power Up
Programming Setup
SECURITY MENU
SYSTEM MENU
CHANNEL MENU
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OPTIONAL REMOTE RELAYS.....................................................................................................52
General
Specific
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Table of Contents
2
SYST
NEMA-4X Enclosure
Circuit Board
Cable
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Figure 11 - Remote Relay Enclosure – Front View
Installation
Figure 12 - Remote Relay Assembly Outline Dimensional & Installation Drawing (P/N 096-2691)
Wiring
Figu
Remote Relay Operation
Figure 14 - Remote Relay Settings
Remote Relay Setup and
Programming
EM MAINTENANCE
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re 13 - Interconnect Wiring Between 7400 & Remote Relay Assembly
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Factory Default
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General
Alarm/Relay Check
TROUBLESHOOTING..................................................................................................................65
General
Channel Test Setup
Table 2 - Identify and Loc
SPARE PARTS
SCOTT HEALTH & SAFET
CONTACTING SCOTT HEA
TECHNICAL SPECIFICAT
FACTORY DEFAULT SETT
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ate Possible Malfunctions During System Failure
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Y WARRANTY
LTH & SAFETY
IONS
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INGS
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Table 3 - Factory Default Settings for Receiver/Controller
CUTOMER WORK SHEET
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Table of Contents
3
LISTING PROGRAMMING SELECTIONS Channel 1
LISTING PROGRAMMING SELECTIONS Channel 2
LISTING PROGRAMMING
LISTING PROGRAMMING SELECTIONS Channel 4
LISTING PROGRAMMING SELECTIONS REMOTE RELAYS
APPENDIX A
Programming Example 1
Programming Example 2
Programming Example 3
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SELECTIONS Channel 3
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108
Table of Contents
4
Introduction
Important Safety Issues & Warnings
The following symbols are used in this manual to alert the user of important instrument ope
This symbol is intended to alert the user to the presence of important operating and maintenance
(servicing) instructions.
Shock Hazard – Disconnect or turn off power before servicing this instrument.
Do not open the case when the uni
Notify all personnel that the unit is out of service before removing from service
Unpacking
All QuadScan II Receivers/Controllers are individually packaged. If the optional remote relay an
it will also be packaged with the receiver/controller. If the optional battery back-up unit is purchased, it will be
packaged separately.
rating issues:
t is powered. Do not open the case in a hazardous environment.
d cable is purchased,
Open each box carefully and remove the items. Identify all items shown in
list for completeness. Examine each item for external damage. If there is any damage or if any item is missing, notify
the factory at:
Scott Health & Safety Customer Service
4320 Goldmine Rd. Monroe, NC 28110 USA
Phone: (704)291-8300
For web and email :
www.scotthealthandsafety.com
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Fax: (704)291-8340
Figure 1
and check yo
ur order and packing
General Description
The QuadScan II Receiver/Controller provides the electronic interface with the remotely located gas transmitters
(oxygen, or combustible). It also provides a conti
alarm displays, and alarm functions which can initiate corrective actions when any undesirable gas concentration is
detected
The receiver/controller is offered in a unique configuration, p
or 3 channels to be purchased within the 4 channel unit. Only the number of channels purchased will be activated for
monitoring in this unit.
If you wish to activate additional channels when less
to purchase the activation codes.
A NEMA-4X wall mounted enclosure contains the microprocessor controlled electronics, displays, and terminal blocks
used for the power input, transmitter 4-20 mA current loop inputs and outputs, relay contact outputs, and remote relay
outputs.
nuous digital display of each monitored gas concentration, various
roviding a complete four channel unit, but will allow 1, 2,
than 4 are purchased, contact the Scott Health & Safety factory
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gures 10 & 11 for Mounting Details &
Model 7400 QUAD-SCAN II
(See Fi
Remote Relay Box P/N 096-2691
Comes with 10 feet of Cable
Wiring Interconnect)
Battery Backup P/N 096-0719
(See Figure 14 for Mounting Details & Wiring
Interconnect)
Figure 1 - Model 7400 QUAD-SCAN II Complete Assembly
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Quick Start
1. Install per the physical installation information found in this ma
mounting requirements.
2. The 7400 can be powered with either 100-270VAC or 24VDC. Refer to Electrical drawings for information
about the power input wiring. Wire according to National Electric Code
Do not apply p
transmitters.
3. Connect your gas transmitter(s) to the 7400. Refer to
into your system at this stage
4. Touch the
through 4. Press the
display next to the channel identification number.
5. Follow the menu trees menus [refer
pre-configured for your specific application, refer to “
save your programming and finish press the
ENTER
must be completely programmed before you can proceed to another channel.
Setup
key and this will complete your programming. When programming other channels, each channel
key to enter t
ENTER
ower until you have finished wiring the complete system, including
Figure 7
)
he programming mode. Use the
key once the correct channel is in “Setup” mode. This is seen on the LCD
to “
Setup & Programming
Factory Default Settings
Escape
key until
nual. Refer to Installation drawings for
. (
No relay contacts should be hard wired
Up
or
Down
key to program channels 1
” for complete details]. Unless your unit was
” for factory default values. To
SAVE SETTIN
GS?
is displayed. Press the
Model 7400 Function Keys
6. Connect common relays [refer “Terminal Block Arrangement” figure for connections]. Refer to “
Relay Operation
7. If optional remote relays are to be used, connect per the “Optional Remote Relays” section of this manual.
8. For proble
Scott Health & Safety representative or the Scott Customer Support team.
ms in startup, refer to the “Troubleshooting” section of this manual. Otherwise contact your local
” for further details on relay functionality.
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Alarm and
Quick Start Programming Menu Tree
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System Menu
Touch Enter Key
Version 1.# (1)
Move through options with
UP/Down Key
Adjust Contrast
Inhibit
: None/All
Set Local Relays
Relay: Common Fail
Failsafe: Yes (3)
F1
Relay: Common Warn
Failsafe: Yes/No
W1
Relay: Common Alarm
Failsafe: Yes/No
A1
Relay: Common Horn
Failsafe: No (3)
W1
Press Escape Key then UP key to
advance to next menu
Set Remote Relays
Remote Relay 1 – 8
Move through all 8 relays with UP
key. Press ENTER to adjust.
Failsafe: Yes/No
W1 (4)
Press Enter k
relay 1 - 8
Time:
##:##
Date:
## / ## / ####
(6)
(2)
Units
F2
F3
F4 (4)
W2 W3 W4 (4)
A2 A3
A1
A4 (4)
... W4
ey to step back to
A4 (4)
(5)
Cal Loop Input
Channel Menu
Touch Enter Key
ON/OFF/IHB: ON
Move through options with
UP/Down Key
Sensor
Full Scale:
Tag:
Damping (S):
Zero DB (%FS): 0 – 5
Inhibit(mA):
Fault(mA):
Setup Warning
Warn Set: ###
Warn Reset: ###
Warn Delay: 0 –10 sec.
Warn Hold: 0 – 7200 sec.
Warn Latch: Yes/No
Setup Alarm
Same values available under
Warning
Cal Loop Output
: 4-
: %/PPM / PPB /None
Six character name
20mA (1
###
0 -10
2.0 – 20.0
0.1 – 20.0
(2)
(2)
)
Security Menu
Touch Enter Key
Security Options
Move through options with
UP/Down Key
Change Password
Lock System
Notes:
1. These values are factory set and cannot be adjusted.
2. To access the submenu associated with these parameters, press the ENTER key. To bypass the
parameters, press the UP/DOWN
key to go back to the main menu.
3. The common fail relay can only be programmed as failsafe. The common horn relay can only be
programmed as non-failsafe (otherwise the horn enunciator woul
continue with the programming.
key. Once a submenu value has been programmed, press the ESCAPE
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d always be on). Press the ENTER key to
4. The relays can be configured for any configuration desired. W = warn, A = alarm, F = fail and the numbers 1
–
4 designate channel number. & = And logic,
“
Remote Relay Operation” for additional information. Press the ENTER key when the programming is
complete and the UP/DOWN key to go to a different menu.
= Or logic and ( ) are use
d to group channels. Refer to the
5. The SET REMOTE RELAYS menu is only available if this option is phys
controller. Otherwise the menu is not displayed.
6. The CONTRAST menu is selected by pressing the ENTER key and then adjusting the contrast with the
UP/DOWN key.
ically connected to the 7400
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Receiver/Controller
General
The QuadScan II Receiver/Controller i
transmitter. The unit has 3 major components:
NEMA-4X wall mounted enclosure
Display/function assembly
CPU/power supply boards
All setup functions are completely programmable usi
internal alarm horn is mounted within the enclosure providing 85 db at 1 ft.
Four 5A SPDT relays are included which are common to all 4 channels. Relays provide the following:
FAIL
WARN
ALARM Activates on a programmed set point corresponding to an increasing or decreasing gas
s a 4 channel gas receiver designed to operate with any 2, 3, or 4 wire gas
ng the switches located on the display/function assembly. An
Activates on
power loss.
Activates on a programmed set point corresponding to an increasing or decreasing gas
concentration, flame signal or any other analog signal.
concentration, flame signal or any other analog signal.
a failure of the current loop signal from the field device or an internal failure such as
Note:
setpoint when monitor
a decreasing gas concentration application such as oxygen, the alarm set point is set lower (e.g. 16%
v/v) than the warn set point (e.g. 19.5% v/v). Although, the alarm set po
detect rising oxygen concentration and the warn setpoint programmed to detect decreasing oxygen
concentration.
HORN
Programmed to activate on for warn, alarm or both.
An optional remote relay assembly in a NEMA-4X wall mount encl
outputs are required. There are six 5A SPDT and two 5A DPDT relays. These relays can be assigned or zoned to
any input channel.
The Quadscan II receiver controller will not operate with out a source of electri
for short term outages either provide another source of electricity such as a battery backup. An optional battery
backup assembly is also available providing 2.5 amp-hours of DC power to the unit. Factory suppl
Health & Safety P/N 004-0002) is a Sonnenschein Part No. A212/35, 12 volt 2.5 amp hour battery.
Warning: Replace the battery only with the same type and rating.
Alarm set points are typically programmed for a higher gas concentration than the warn
ing an increasing gas concentration, including toxic and combustible gases. For
int can be programmed to
osure can be provided when individual alarm
city. If you require an electricity source
ied battery (Scott
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Failure to do so may be dangerous. Dispose of batteries per applicable
Scott Health & Safety or your local Scott authorized distributor.
NEMA-
The enclosure measures 9.32 inches high x 9.19 inches wide x 5.38 inches deep (233 mm x 203 mm x 136 mm). It
provides a watertight, dust tight and corrosion resistant enclosure for outdoor or indoor mounting.
4X Wall Mounted Enclosure
A door covers the digital/function front panel and can open to the left or
right for easy mounting in restricted areas. All displays; gas
concentration,
through the clear opening in the enclosure door. A cover plate is
located at the bottom front area of the enclosure and when it is
removed, access is available for all the terminal strips used for input
an
d output wiring. See Figure 2A
cover plate.
Figure 2- Model 7400 QuadScan II
alarm LEDs, and the function switches, are visible
local, state and federal regulations or contact
for correct installation of bottom
Figure 2A – Enclosure Side View
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Display/Function Assembly
The individual visual display of absolute value of the gas c
active channels provides the status of the gas/flame detection system.
Operator intervention and/or automatic alarm corrections can be made from the information displayed by this unit.
Gas Concentrat
of the four.
Individual Channel Status is displayed by a 2 color LED for each active channel:
Channel OK
Current Loop Fault Flashing yellow (flashin
ion is displayed on a LCD in units of PPM, PPB, % and none (flame applications) in any combination
Green
yellow).
oncentrations, alarm status, and channel status for all
g until the reset button is pressed, and then it becomes solid
Channel Inhibited
Individual alarm statuses are displayed for warn and alarm events by a yellow (warn) and re
each active channel. The individual alarm LEDs flash when an alarm condition is detected and remain flashing until
acknowledged by the reset button.
The function section of the unit is used for all programming and setup requirements. Five tactile feel switches are
provided to implement the following functions:
SETUP
the right on the LCD each time the switch is activated.
UP To scroll up through the various channels or programming options
DOWN
ENTER
Flashing yellow/green (an inhibited channel cannot be set to steady color)
d (alarm) colored LED for
To activate programming entry to the system. This also moves the alphanumeric selection one position to
.
To scroll down through the various channels or programming options.
To enter the required programmed option selected from the UP or DOWN switches.
ESCAPE
eventually return to the gas concentration display.
To return to a prev
ious menu or selection each time the switch is activated. This will
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NOTE: During the programming mode, if a switch is not activated for 20 minutes, the display automatically returns to
the gas concent
ration display and all previous programming will be lost.
Figure 3 - Model 7400 Front Panel Push Buttons
CPU/Power Supply Boards
The power supply board is located on the inside back surface of the enclosure. The CPU/display board is located
directl
y behind the display/function panel. They are connected together via a ribbon cable.
The CPU board is used to store the system configuration, operation data and all parameters entered from the function
switches on the display/function assembly.
All inform
allows all information to remain stored during a power disconnect.
The power supply board accepts AC and DC power inputs to the system and supplies the va
and the transmitter loops. The system will operate on any AC voltage between 90 to 280 VAC, 50/60 Hz. or DC
voltage between 10 to 30 VDC (nominal 24 VDC). When a battery backup system is connected to the unit and if the
AC power
There are 4 common relays located on the power supply board providing SPDT 5A contacts. The warn and alarm
relays can be programmed for normally energized (fail safe) or normally de-energized operation as well as
latching/non-latching. The fail relay operates in a normally energized (failsafe) mode only. The horn relay operates in
a normally de-energized mode only.
ation is stored in non–volatile electronically erasable programmable read only memory (EEPROM), which
should fail, the system will automatically switch over to DC power without interruption.
rious circuit requirements
When any of the following conditions exist, the relay
Fail – When the 4-20 mA loop from the transmitter falls to the programmed fault level.
Warn – When a gas concentration exceeds a pre- set programmed level (set point), this is normally not a
hazardous condition. When this happen,
monitored.
Alarm – When a gas concentration exceeds a pre-set programmed level (set point) which is set higher or lower
for oxygen monitoring than the warn relay. When this happens,
Horn – This relay provides a contact for a remote horn and will change state on either/or warn or alarm condition.
The local buzzer will also activate. The horn relay will de-energize (turn off) once the silence/rese
pushed
EVEN WHEN A WARN/ALARM EVENT IS STILL OCCURRING.
contacts change state:
the increasing or decreasing gas level concentration needs to be closely
corrective action should take place.
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t button is
Terminal blocks are provided for the following input and output requirements:
TB1 – 2, 3, or 4 wire 4 – 20 mA inputs for Channels 1 and 2
TB2 – 2, 3, or 4 wire 4 – 20 mA inputs for Cha
TB3 – AC power input
TB4 – Battery backup input
TB5 – 2 wire 4 – 20 mA outputs for 4 channels
TB6 – Remote relay outputs for 8 relays
TB7 – Contact outputs for fail, warn, alarm, and horn relays provide normally closed (NC), common (C) and
no
rmally open (NO) contacts for customer use.
WARNING
SHOCK
HAZARD:
RISK OF ELECTRICAL
SHOCK- DISCONNECT
OR TURN OFF POWER
BEFORE SERVICING
THIS EQUIPMENT.
nnels 3 and 4
Figure 4 - Terminal Strip Layout
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Installation
The installation information is presented in three sections:
Selecting the appropriate physical location
Methods of physical mounting
Directions for wiring
N
ote: Remote relay installation is covered in a separate section.
Selecting the Physical Location
The specific location for the receiver/controller is the responsibility of the user.
Use the following guideline to determine the appropriate location for th
Do not exceed the temperature range of -13º F to 122º F (-25º C to 50º C)
Must be located in non-hazardous areas
Should avoid extreme vibration, dampness and temperature variations
Avoid direct sunlight or provide a sun screen
Should have easy vi
sibility and access for the operator
e unit:
Must allow sufficient clearance for wiring, maintenance, set up and programming
WARNING
reading may be low resulting in
Met
hods of Physical Mounting
The enclosure dimensions are 9.3 inches high x 9.2 inches wide x 5.4 inches deep and weighs 4 lbs. (237mm H x
233mm W x 137mm D and 1.75 Kg) Refer to
Locate the 6
the following steps before moving to the job site. The display/function assembly and bottom front cover plate will need
to be removed from the base
power hasn’t been wired in yet.
connector.
1. The display/function assembly can be removed
mounting holes at the desired location and drill for the proper bolt size. It may be advisable to perform
located on the
: If the equipment is not installed as prescribed by the manufacturer, the accuracy of the
Figure 5
enclosure to access the mounting holes. Unless this is an instrument relocation, the
Be sure power is removed from the unit before disconnecting the flat ribbon
right side,
closest to the back of the enclosure.
for recommended clearances and mounting hole locations.
by inserting a small blade screwdriver into the 3/8 "long slot
2. Insert the screwdriver into the slot and lever it outwards, dislodging the hinged section of the base enclosure.
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3. Move t
4. Tilt the assembly away from the base enclosure and unplug the ribbon cable from the display circuit board.
5. On the
Use the following steps to attach the assembly to the base:
1. Position the display assembly over the base.
2. On the left side, move the hinge section out from the assembl
3. Push the top of the hinge section in towards the side of the assembly, locking the left side to the base.
he hinged section away from the side of the enclosure, disengaging it from the base.
Power must be off before removing ribbon cable.
left side, follow steps 1 – 3. The assembly will then lift clear of the base.
Caution: All circuit board components are now exposed. Extreme care must be taken not to
damage these components.
Using #8 mounting screws or bolts, mount the enclosure to
mounting holes in the enclosure.
the wall or other suitable structure via the 6
y and make sure it has engaged the hinge rod.
4. Pull the right side of the assembly away from the base and reconnect the ribbon cable.
5. On th
Note:
or conduits when mounting the enclosure. Use all NEMA-4X rated comp
rating of the enclosure.
e right side, follow steps 2 – 4 to complete closing the assembly to the base.
The bottom of the enclosure is pre-drilled for cable entry. Clearance should be allowed for the cables
onents for cable entry to maintain the
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Figure 5 - Mounting Dimensions of Model 7400
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Directions for Wiring
Remove the cover plate located at the front bottom of the enclosure; this will expose all terminal blocks. The
–
power supply board is labeled with the appropriate function and wire designation to implement correct wire hook up.
Refer to
holes in the
Incoming AC power to Termina
or circuit breaker and is to meet all requirements of applicable local and state electrical codes. The power switch
and/or circuit breaker are to have proper electrical r
switch/circuit breaker in close proximity to the 7400 Receiver. Power ON is to be so designated with an “I” and power
OFF with an “O”. Wiring from the power source to the 7400 receiver is to be service rated in accordance with local
and state electrical codes.
Refer to
and Controller.
Figure 6
Figure 7
for the terminal block layout. Route the power, ground, relay and signal wires through the entry
bottom of the enclosure. Note: Power, grounding and relay wiring must be separated from signal wiring.
CAUTION: Common relay contacts and optional remote relay contacts to be wired to external
devices should not be connected at this time. Programming must
are connected.
relays to activate. If alarm by pass systems are in place and can be activated, this caution can be
ignored.
for the current loop wiring from transmitter to Model 7400 Quad Scan II.- Four Channel Receiver
be completed before wires
Connecting the wires before programming is complete, may cause alarms and
l Block TB3 (See
Figure 6
) is to be connected from a certified/approved power switch
atings to operate as a mains disconnect device. Locate the power
main I/O
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Figure 6 - Terminal Block Arrang
ement on Main I/O – Power Supply Board
CAUTION: All relay contacts are rated 5A Resistive Load. Any in-rush current above this value
can cause damage to the unit
Dry Contact Input Wiring
Dry-contact inp
smoke or fire detectors.
uts can be applied into the model 7400 analog input channel. This can be done, for example, for
Figure 8
illustrates how to wire a normally open dry contact into the analog input.
Figure 7 – Transmitter Wiring to Model 7400
.
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IMPORTANT: This application requires 24VDC +2
case when the AC is used to power the 7400.
values significantly different than 24VDC.
To use this application, the full scale range i
approximately 100% of scale when the field contacts operate. Connect resistors and relay as in the figure.
s set to 0 – 100%. The reading will be 0 with no alarm condition and
% to be present between +24 and COM as is typically the
Operating the 7400 off of battery backup could provide voltage
Figure 8 - Wiring of Normally Open
Field Contact into Model 7400
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Figure 9 - Battery Backup (P/N 096-0719)
Outline & Interconnection Wiring
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System Operation
General
The QuadScan II allows up to 4 inputs of 0/4 - 20 mA and converts these inputs to digital displays on a LCD. An input
cu
rrent of 4 mA corresponds to a display of 0.00, and an input current of 20 mA corresponds to the programmed full
scale digital display. Displays are checked against programmed alarm levels (set points) to illuminate LEDs, activate
relays, and sound the in
current loops.
Display Readings
The LCD is capable of displaying digital ranges from 000 to 1999. A decimal point may appear in the digital display,
which is set aut
digital ranges are shown below.
omatically by the programmed channel full-scale display. Possible full-scale displays with respective
Full Scale
1.00 – 9.99
10.0 – 99.9
100 –
1999
ternal horn. The input current loops are also used to generate isolated 4 - 20 mA output
Decimal Precision
2 digits
1 digit
0 digits
-
The decimal point is fixed and does not change once set.
The LCD may be programmed for one of the three gas concentration units or none at all.
% Percent
PPM Parts Per Million
PPB Parts Per Billion
none
Contrast may be set for the LCD during setup and programming, which may provide a clearer view of the digital
display from various angles.
The LCD can be programmed with up to a maximum of six (6) alphanumeric characters to display specific customer
information such as transmitter location, area identification etc.
Visual Indications (LEDs)
The visual indications located on the digital/function assembly are divided into two distinct sections; channel status
and alarm status. These sections are l
--
ocated just below the LCD.
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Channel Status
The channel status essentially provides a summary of the health of each active channel. Four LEDs are used,
one for each of the 4 channels. Each LED provides 3 functions:
Channel OK - Green
Channel in Fail - F
Channel Inhibited - Flashing yellow/green
Alarm Status
Each channel has 2 LEDs, warn (yellow), for low alarm status and alarm (red)
for high alarm status. The operation of these LEDs are contro
indication (gas concentration ) and the alarm settings(set points). During normal
operation these LEDs are not illuminated, when an alarm condition is detected,
its respective LED will illuminate in a flashing mode.
The warn LED can be
be illuminated at the same time, depending on the level of the gas concentration
detected. The LEDs will remain flashing until the alarm condition has passed or
until the alarm reset pushbutton is
pressed, the LEDs will remain illuminated but not flashing. If the alarm is programmed as latching, the LED will
extinguish only after pressing the alarm reset when alarm condi
point). Warn represents the first stage of alarm while alarm represents a more serious event.
illuminated by itself or both the warn and alarm LEDs can
pressed. If the alarm condition is still present after the alarm reset has been
lashing yellow, (solid yellow when reset button is pressed)
lled by the display
tions are not present (above or below the reset
Current Loops
During factory calibration, each current loop is exposed to a precise 4.00mA and 20.00mA input sig
stores as digital values in EEPROM. These values are then used to determine the unknown input current during
normal operation. The computed mA input value is then used for computing the digital display, where 4mA is
equivalent to 0.00, an
nal which the CPU
d 20.00mA is equivalent to the programmed full-scale display.
WARNING
the programmable fault level. The factory default level is 3.5mA but can be pr
Applications such as oxygen deficiency monitoring must have the FAULT level programmed below 4 mA.
When the input signal reaches the fault level, the relays are turned off after the alarm reset button is pressed.
Therefore sett
: In normal operation the 4
ing the alarm level below 4mA (0.0% v/v O2) will prevent the 7400 from shutting off the warn and
alarm relays accidentally.
-20mA input current loop is checked for a signal that falls down to or below
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ogrammed as low as 1.0mA.
Oxygen applications monitoring both increasing AND decreasing oxygen
concentration must have the INHIBIT level programmed below 4
signal reaches the inhibit level, the relays are turned off. Therefore setting the alarm level
below 4mA (0.0% v/v O2) will prevent the 7400 from shutting off the warn and alarm relays
accidentally.
mA.
When the input
Current Loop Outputs
Each channel
following conditions:
Alarm inhibit:
Channel Off:
Input Under range (below 4mA):
Internal Faults:
provides a 2 wire isolated current loop output which follows the current loop input, except during the
C
Alarm and Relay Operation
When an increasing or decreasing toxic, explosive, or oxygen deficient gas condition or flame is detected, the
QuadScan II provides the means to alert to this potential ha
associated with toxic or combustible gas atmospheres, while decreasing concentrations are associated with oxygen
deficient atmospheres.
An alarm due to an increasing concentration is activated (changes sta
above the set point and is inactive when the digital indication is at or below the reset point. Flame detectors provided
by Scott Health & Safety provide an increased output analog signal when a flame is
Current loop output goes to programmed inhibit level.
Current loop output goes to programmed inhibit
Current loop output follows the current loop input until it reaches the
programmed fault level. At that stage, the value remains at the fault level no matter how
far down the current input goes.
urrent loop output goes to the programmed fault mA level.
level.
zard. An increasing gas concentration is normally
te) when the displayed digital indication is at or
detected.
An alarm due to a decreasing concentration is activated (changes state) when the digital indication is at or below the
set point and inactive when the digital indication is at or above the reset point.
Protection is provided by the activation (ch
devices such as deluge systems, shut down systems, horns, beacons, etc. Two common relays (warn and alarm)
each with 5A SPDT contacts provide this interface. An optional relay assemb
can be configured for any channel.
Set Point - A programmed numerical value that is compared to the actual gas concentration or percentage of full
scale. When the concentration is equal to this numerical value, the associated relay activates (changes state)
immediately. (See Set Delay).
Set Delay
concentration is established at or above the set point (toxic/ co
point (oxygen deficient applications) for that specific programmed period of time.
(Off Time) - A delayed relay activation can be programmed for a specific time delay until a constant gas
ange of state) of alarm relays, which can be used to activate protective
mbustible or flame applications) or at or below the set
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ly provides eight additional relays that
This timed delay can prevent nuisance alarms that may occur due to such things as lightening storms, etc. The off
tim
until the time expires.
e delay can be programmed for up to 10 seconds, and once activated the timer is decremented once a second
If the channel is not inhibited (channel status LED flashing),
the associated relay(s) will be affected (non-energized
relays
will be energized, and energized relays will be de
energized). Timer activation can be set to 0 at which time
relay activation will be immediate as described under Set
Point.
Reset Point - A programmed numerical value, which is
compared to the actual ga
concentration is equal to this numerical value, the
associated relay de-activates (changes state) immediately
(See Reset Delay). This is sometimes referred to as
hysteresis.
s concentration. When the
-
Reset Delay
be programmed for a specific time delay to provide
additional on time for exhaust fans or other corrective
devices.
The on time delay can be programmed for up to 7200
seconds (2 hours) and once activated the timer is
decremented once a second until th
When the reset timer has expired, the alarm(s) are
deactivated and the channel warn and alarm LEDs are
turned off, unless the alarm(s) are programmed for latching.
Latching alarms require depressing the alarm reset in order
to deactivate t
while the reset timer is in the process of counting down will
automatically expire the timer. The alarm will be
deactivated. Timer activation can be set to zero (0)
disabling this feature.
(On Time) - A delayed relay de-activation
e time expires.
he alarm. Pressing the alarm reset button
can
Figure 10 - Alar
m Set For Increasing or Decreasing Gas Concentrations
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Latching Alarms
Latching alarms describe the behavior of the software emulating a self latching relay. The coil is energized through
one of its own contacts, thereby holding itself energized. This typ
circuit for the relay to be de-energized. This is the function of the alarm reset button.
energized. This describes a non-failsafe relay. When an alarm relay is programmed to be fail
its coil remains energized in normal, no alarm condition, and de-energizes during an alarm. This
permits the relay contacts to be used to detect power failures as well as their assigned function.
Safety Suggestion!
relays, failsafe, so that power failures may be sensed. A separate power source is required for the
alarm devices, e.g. horns & lights, if used to detect power failures.
e of relay requires an interruption in the latching
This feature is implemented in software for alarms warn and alarms programmed with the latching
option. Once an
state even though the original alarm conditions have returned to normal. The LED and relay(s) will
not be returned to normal until the alarm condition has subsided and the alarm reset button has
been pressed.
Energized Relays (Fail Safe)
Normally, an alarm relay will remain de-energized until an alarm occurs, at which time the coil is
alarm has occurred, the associated LED and relay(s) will be held in their alarm
It is a safe practice to make all
optional remote relays programmed as fault
safe,
The common fault relay is energized (fai
The warn and alarm relays by factory default are set for de-energized operation but can be programmed otherwise.
Note: Any relay, programmed as energized (fail safe), will have contact operation reversed to the te
strip labeling. All labeled normally open (NO) contacts will operate as normally closed (NC) and all labeled
(NC) contacts will operate as (NO).
Common Alarm Relays
There are four SPDT common alarm relays located on the CPU/power supply board.
Faul
t Relay Activated when any channel fault is detected.
Warn Relay Typically activated when any channel low alarm set point is exceeded. This relay can be
programmed to activate off any one channel or group of channels for either warn and/or
alarm level.
A
larm Relay Typically activated when any channel high alarm set point is exceeded. This can be
programmed to activate off any one channel or group of channels for either warn and/or
alarm level.
Horn Relay This relay can be programmed to activate off any
warn and/or alarm level.
lsafe) and cannot be programmed otherwise
rminal
one channel or group of channels for either
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All relay contacts are rated 5 A
250VAC.
The warn and alarm relays can be programmed for
energized (failsafe) or de-energized (non-failsafe). This
is done in the SYS
latching operation is programmed for each channel
input. This is done in the CHANNEL MENU. When
programmed for latching operation, the reset button
must be depressed to release the relay from this
condition, but will only rel
condition has passed. It is possible to have one or more
channels programmed as latching and one or more
programmed as non-latching. When this happens, if
channel inputs from both groups go into alarm/warn
then the latching pro
non-latching program.
Different corrective actions are normally required when
sensor/transmitters are located in dissimilar areas. Set
points could differ for the gases being monitored,
therefore, the common relays will not provide the
required results when this situation occurs. However
Scott Health & Safety has anticipated such situations
and can provide an optional remote relay assembly,
allowing alternative alarm combinations.
TEM MENU. The latching or non
gram takes precedence over the
Resistive
ease the relay if the alarm
24 VDC
-
-
Fail Relay
The common fail relay is provid
the energized state (failsafe). The remote relay
assembly allows for a relay to be configured as a non
failsafe fault output. There are no set or reset timers
associated with fail alarms. When a fault is detected,
fail alarms are ac
conditions are cleared, fail alarms are immediately de
activated.
When a fault condition is detected, the channel status
LED will change from a solid green to a flashing
yellow/green. It turns solid yellow if acknowled
state from energized to de-energized.
If a channel is in a warn or a warn and alarm condition when a fault occurs on that channel, Table 1 defines the
relay(s) state when in a latched or
ed only to be used in
-
Table 1 – Relay States
tivated immediately. When the fault
-
ged by pressing the reset button.) The common fail relay will change
unlatched programmed mode.
(when in a Latched or Unlatched
programmed mode)
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