UTC Fire and Security Det-Tronics R8471B User manual

Instructions 95-8401
H2S Controller
R8471B
2.1 8/07 95-8401

Table Of Contents
Section I - General Information
DESCRIPTION .................................................................................................1
FEATURES...........................................................................................................1
APPLICATION INFORMATION............................................................................1
SPECIFICATIONS................................................................................................2
Controller.......................................................................................................2
Sensor ...........................................................................................................3
SYSTEM OPERATION.........................................................................................3
Sensor ...........................................................................................................3
Optional Transmitters ...................................................................................4
Controller.......................................................................................................4
Section II - System Installation
INSTALLATION ....................................................................................................9
Sensor Location.............................................................................................9
General Wiring Requirements.....................................................................10
Sensor Wiring .............................................................................................10
Controller Wiring .........................................................................................12
Controller Programming...............................................................................15
INSTALLATION CHECKLIST.............................................................................16
Section III - System Startup
STARTUP PROCEDURE...................................................................................16
SETPOINT ADJUSTMENT.................................................................................17
Setpoint Display Mode.................................................................................17
Setpoint Adjustment Procedure...................................................................17
CALIBRATION....................................................................................................18
Calibration Procedure..................................................................................18
Current Output Calibration...........................................................................20
Section IV - System Maintenance
ROUTINE MAINTENANCE................................................................................20
Manual Check of Output Devices................................................................20
Checkout in Normal Mode...........................................................................20
Hydrophobic Filter ......................................................................................20
Sensing Element Replacement...................................................................21
TROUBLESHOOTING .......................................................................................22
REPLACEMENT PARTS....................................................................................22
DEVICE REPAIR AND RETURN .......................................................................23
ORDERING INFORMATION..............................................................................24
Accessories .................................................................................................24
Calibration Equipment .................................................................................24
Replacement Parts......................................................................................24
APPLICATION ASSISTANCE.............................................................................24

Section I
General Information
DESCRIPTION
The R8471B Hydrogen Sulfide (H2S) Controller is a
single channel, rack mounted device that operates
in the ranges of 0 to 100, 0 to 50 or 0 to 20 parts per
million (ppm). The controller provides continuous
monitoring of a Det-Tronics electrochemical H2S
sensor or any H2S sensor/transmitter assembly
capable of generating a 4 to 20 ma dc signal.
Controller response includes actuation of solid state
or optional relay outputs for direct control of field
response devices, a full array of faceplate indicators,
as well as an optional 4 to 20 milliampere output for
transmitting system information to other devices.
FEATURES
•Controller accepts a 4 to 20 ma input, ensuring
compatibility with a Det-Tronics electrochemical H2S
sensor or a variety of H2S sensor/transmitter assem-
blies.
•Digital display, bar graph display, and high intensity
LEDs indicate important system status information.
•AutoCal feature provides easy and accurate calibra-
tion.
•Microprocessor based controller is easily field pro-
grammable.
•Base model is furnished with solid state alarm and
fault outputs.
•Premium model is furnished with relay outputs and a
4 to 20 ma dc output.
•Current output is selectable for isolated/non-isolated
operation.
•Rack compatible with Det-Tronics R7400 series
flame controllers.
•Variety of racks available in 4U or 3U height configu-
ration.
APPLICATION INFORMATION
Hydrogen sulfide is a colorless, highly toxic gas. It
is frequently found in oil and natural gas, sewage
disposal or treatment systems, as well as a variety
of industrial processes. Typical operations that
encounter H2S include:
• Oil and natural gas exploration and production
• Refineries
• Sewers
• Sewage treatment plants
• Chemical plants
• Paper mills.
The ability to electronically monitor the level of H2S is
essential in many potentially hazardous environments.
In low concentrations hydrogen sulfide has the odor
of rotten eggs. However, at higher concentrations
or after prolonged exposure, it deadens the sense
of smell. Therefore, depending on human senses
alone to estimate the concentration of H2S is totally
unreliable.
2.1 ©Detector Electronics Corporation 2007 8/07 95-8401
INSTRUCTIONS
H2S Controller
R8471B

95-840122.1
The actual effect of H2S on an individual depends on
several factors:
1. Concentration level of the exposure
2. Length of time exposed
3. Exposure frequency
4. Ability to tolerate H2S.
Table 1 shows some of the effects of breathing H2S
gas.
SPECIFICATIONS
CONTROLLER
OPERATING VOLTAGE—
24 vdc. Can operate in the range of 18 to 32 vdc.
NOTE
When an I.S. barrier is used, the input voltage
(measured at the controller) must be between 23
and 26.6 vdc to ensure proper operation of the
sensor and barrier.
POWER CONSUMPTION (controller only)—
Base model: 0.7 watt nominal, 1.3 watts maxi-
mum (25 ma nominal, 50 ma maxi-
mum at 24 vdc).
Premium model: 1.2 watts nominal, 3.5 watts maxi-
mum (50 ma nominal, 145 ma max-
imum at 24 vdc).
Maximum startup current is 0.6 ampere for 10
milliseconds. Power supplies with fold back current
limiting are not recommended.
MAXIMUM RIPPLE—
Ripple should not exceed 5 volts peak-to-peak. The
sum of dc plus ripple must be ≥18 vdc and ≤32 vdc.
TEMPERATURE RANGE—
Operating: +32°F to +140°F (0°C to +60°C)
Storage: –49°F to +185°F (–45°C to +85°C).
HUMIDITY RANGE—
5 TO 99% R.H., non-condensing.
OPERATING RANGE—
0 to 100, 0 to 50 or 0 to 20 ppm.
ACCURACY—
±3% of full scale over specified temperature range.
SOLID STATE OUTPUTS (Base model only)—
The outputs are open collector transistors with a 100K
resistor from the collector to emitter with the emitter
grounded, rated 100 milliamperes at 32 volts dc
maximum.
RELAY CONTACTS (Premium model only)—
Selectable normally open/normally closed contacts
rated 5 amperes at 30 vdc/250 vac.
CURRENT OUTPUT (Premium model only)—
4 to 20 milliamperes dc current, with a maximum
external loop resistance of 600 ohms at 20 to 32 vdc.
DIMENSIONS—
See Figure 1.
SHIPPING WEIGHT (approximate)—
2.0 pounds (0.9 kilogram).
SYSTEM APPROVAL—
The R8471B Controller, base and premium model in
3U and 4U height, has been tested and approved by
FMA. It can be used with any FMA approved sensing
device capable of generating a 4 to 20 ma input.
FMA approval of the R8471B Controller, however,
does not include or imply approval of input devices
such as sensors or transmitters, or devices connected
to the controller outputs. To maintain FMA system
approval, all equipment connected to the controller
must be FMA approved.
NOTE
Ensure sensor hazardous (classified) location
rating is applicable for the intended use.
Concentration Effect
1 ppm Detectable by odor.
10 ppm Allowable for 8 hours exposure
(OSHA).
Over 20 ppm Protective equipment required.
100 ppm Kills smell in 3 to 15 minutes.
May burn eyes and throat.
200 ppm Kills smell rapidly. Burns eyes
and throat.
500 ppm Victim loses sense of reasoning
and balance. Respiratory distur-
bances in 2 to 15 minutes.
Prompt artificial resuscitation
needed.
700 ppm Victim becomes unconscious
quickly. Breathing will stop and
death will result if not rescued
promptly. Immediate artificial re-
suscitation required.
1,000 ppm Unconscious at once. Permanent
brain damage or death will result
unless rescued promptly.
Table 1—Effects of H2S

95-840132.1
SENSOR
OPERATING RANGE—
0 to 100 ppm.
TEMPERATURE RANGE—
Continuous operation: –40°F to +105°F
(–40°C to +40°C).
Intermittent operation: –40°F to +130°F
(–40°C to +55°C).
Recommended storage: +32°F to +68°F
(0°C to +20°C).
HUMIDITY RANGE—
Continuous: 15 to 90% RH.
Intermittent: 0 to 99% RH.
ACCURACY—
±10 percent of applied gas concentration or ±3 ppm,
whichever is greater.
RESPONSE TIME—
20 percent full range within 12 seconds, 50 percent
full range within 30 seconds when H2S concentration
equal to full scale is applied.
DRIFT—
Less than 2 ppm per month.
ENCLOSURE MATERIAL—
316 stainless steel.
SENSOR RATINGS—
The C7064E (explosion proof) is CSA certified and
designed to meet FM requirements for Class I,
Division 1, Groups C and D.
The C7064C (intrinsically safe) is CSA certified and
FM approved for Class I, Division 1, Groups A, B, C
and D.
DIMENSIONS—
See Figure 2 for dimensions of the C7064E Sensor
and Figure 3 for dimensions of the junction box.
SHIPPING WEIGHT (Approximate)—
2.5 pounds (1.1 kilograms).
SYSTEM OPERATION
SENSOR
The C7064C (intrinsically safe) and C7064E
(explosion proof) H2S Sensors use an electrochemical
sensing element to detect the presence of hydrogen
sulfide gas. The electrochemical sensing element
provides improved accuracy and reliability, and
also extended calibration intervals when compared
➛
➛
9.3 (23.6)
1.0
(2.5)
7.0*
(17.8)
➛
➛
➛
➛
A1526 *4U DIMENSIONS SHOWN, 3U HEIGHT IS 5.2 (13.3)
4.05
(10.3)
3/4 INCH
STANDARD PIPE THREAD
A1347
1.75
(4.5)
2.0
(5.0)
Figure 2—Sensor Dimensions in Inches (Centimeters)
3.77
(9.6)
1.28
(3.3)
3.46
(8.8)
4.7
(11.9)
2.7
(6.9)
5.2
(13.2)
5.86
(14.9)
B2281
Figure 3—Junction Box Dimensions in Inches (Centimeters)
Figure 1—Controller Dimensions in Inches (Centimeters)

95-840142.1
to ordinary solid state type sensors. A significant
property of the sensing element is its highly
specific response to H2S. Since many commonly
encountered gases have little if any effect on the
electrical response of the sensor, false indications
caused by the presence of these gases are greatly
reduced. In addition, high concentrations of H2S do
not adversely affect the sensor.
The sensor housing contains the transmitter circuitry
for generating a linear 4 to 20 milliampere dc output
signal, corresponding to levels of H2S from 0 to full
scale.
The sensor uses a hydrophobic filter to protect the
electrochemical sensing element from contamination
by dirt and moisture. Unlike metal filters that
significantly restrict the passage of H2S gas to the
sensing element when the surface is coated with
water, the hydrophobic filter sheds water and will not
inhibit the flow of H2S gas to the sensing element.
As with any filter, the hydrophobic filter must be kept
free of contaminants to allow H2S gas to reach the
sensing element.
The hydrophobic filter and electrochemical sensing
element can be replaced quickly and conveniently in
the field.
NOTE
If an intrinsically safe sensor is used with the
R8471B, it must be powered through an approved
barrier in order to maintain its intrinsically safe
rating.
Sensor Cross Sensitivity
Table 2 shows the response of a typical
electrochemical H2S sensor when exposed to
100 ppm concentrations of various commonly
encountered substances. Note that 100 ppm
concentrations of some substances are not normally
present in most applications involving H2S detection
systems.
OPTIONAL TRANSMITTERS
The sensor contains the transmitter circuitry for
generating a 4 to 20 ma signal, eliminating the
need for a separate transmitter. If the application
requires calibration at the sensor location or various
other special transmitter features such as relay
contacts or visible annunciators, a variety of Det-
Tronics transmitters are available for use with either
electrochemical or solid state H2S sensors. Refer to
the “Ordering Information” section of this manual for
more information.
CONTROLLER
Faceplate Description
The controller faceplate provides LEDs for
identifying status conditions, a digital display and
bar graph display for indicating the sensor input,
and pushbuttons for programming, calibrating and
resetting the system. See Figure 4 for the location of
indicators and pushbuttons.
1. Digital Display – The digital display provides a
continuous reading (in ppm) of the sensor input
in both the Normal and Calibrate modes. In the
event of a fault, it identifies the nature of the fault
using an alpha-numeric code. In other operat-
ing modes it shows the alarm setpoints and pro-
grammed calibration gas concentration. A nega-
tive zero drift condition is indicated by a minus
(–) sign in the left hand digit. Since this display
is always lit, it also functions as a power indicator
(except during the power-up time delay, when the
FAULT LED is on and the digital display is off).
NOTE
In the event of an over-range condition, the digital
display flashes and the highest reading latches on
until reset. The user must exercise caution if an
over-range reading is indicated, since a dangerous
condition could exist. The hazardous area should
be checked with a portable detection instrument to
determine the actual level of H2S gas present.
2. Bar Graph Display – The 20 segment bar graph
display provides a reading of sensor input in
increments of 5% of full scale.
3. High Alarm LED – Flashes in response to a sen-
sor signal that exceeds the high setpoint.
4. Auxiliary Alarm LED – Flashes in response to a
sensor signal that exceeds the auxiliary setpoint.
5. Low Alarm LED – Flashes in response to a sen-
sor signal that exceeds the low setpoint.
Table 2—Cross Sensitivity of Electrochemical Sensor to
100 ppm Concentrations
0 ppm <1 ppm <15 ppm <–30 ppm –20 ppm
HCN CO SO2NO2Cl2
C
2H4NO
H
2
HCl

95-840152.1
NOTE
The alarm LEDs flash when the setpoint is
exceeded and are on steady (until reset) when
the H2S level drops below the setpoint, whether
the corresponding alarm output is latching or non-
latching.
6. CAL LED – Illuminated while the controller is in
the calibrate mode.
NOTE
In the Setpoint Display or Setpoint Adjust mode, a
flashing alarm LED identifies the particular setpoint
currently being indicated on the digital display. A
flashing CAL LED indicates that the programmed
calibration gas concentration in ppm is currently
being shown on the digital display.
7. FAULT LED – Flashes upon detection of a system
fault and is on steady during the power-up time
delay.
8. RESET Pushbutton – Used for various system
programming and calibration functions as well as
for resetting the controller.
9. SET Pushbutton – Used for various system pro-
gramming and calibration functions.
Setpoints
The R8471B Controller has independent Low, High,
and Auxiliary alarm setpoints, with corresponding
outputs.
The programmed calibration gas concentration in
ppm is also displayed and adjusted with the alarm
setpoints. This value must be equal to the ppm
concentration of the calibration mixture that is used
for the span adjustment.
The adjustment range in ppm is:
The alarm setpoints and calibration gas concentration
can be checked by pressing the RESET pushbutton
located on the front panel of the controller. See
“Setpoint Adjustment” and “Calibration” sections of
this manual for additional information.
Outputs
The R8471B Controller is available in a Base version
and a Premium version. The differences between
the two models are the output configuration and
programming options.
BASE MODEL
The base controller is furnished with open collector
transistor outputs (rated 100 milliamperes at 32 volts
dc) for the Low alarm, High alarm, Auxiliary alarm,
and Fault circuits. The normally de-energized alarm
outputs are energized when their corresponding
setpoints are exceeded. The fault output is normally
energized and becomes de-energized upon detection
of a system fault. The low alarm, auxiliary alarm, and
fault outputs are non-latching. The high alarm output
is latching.
PREMIUM MODEL
The premium model is furnished with a set of four
relays in place of the four solid state outputs. The
relays have SPST contacts rated 5 amperes at 30 vdc
or 250 vac.
This model also includes a selectable isolated/non-
isolated 4 to 20 ma dc current output for transmitting
system information to other devices. The linear 4
FAULT LED
CAL LED
BAR GRAPH
DIGITAL DISPLAY
AUXILIARY LED
HIGH LED
RESET
PUSHBUTTON
SET
PUSHBUTTON
LOW LED
A1429
1
2
3
9
5
6
7
8
4
Figure 4—Controller Front Panel
Range: 0 to 100 0 to 50 0 to 20
Low alarm: 5 to 40 1 to 25 0.5 to 10
High alarm: 10 to 60 2 to 45 1 to 18
Aux. alarm: 5 to 99 1 to 45 0.5 to 18
Cal. gas: 30 to 99 15 to 45 6 to 18

95-840162.1
to 20 ma output corresponds to levels from 0 to full
scale. If a system fault is detected, the output drops
to less than 1.0 ma. The current output can be
calibrated in the field to ensure maximum accuracy.
(Refer to the “Calibration” section of this manual for
details.)
PROGRAMMING OPTIONS
(PREMIUM MODEL ONLY)
Each of the four relays is field selectable for either
normally open or normally closed contacts using
jumper plugs located on the printed circuit board
inside the controller. (See Table 3.)
The alarm relays are also switch programmable for
either normally energized or normally de-energized
operation (programmable as a group only, not
individually) . The fault relay is normally energized.
The low and auxiliary alarm relays are programmable
for either latching or non-latching operation. The
high alarm relay is always latching and the Fault
relay is non-latching. Latching relays are reset using
either the RESET pushbutton on the front panel of the
controller or an external reset switch.
The 4 to 20 ma circuit is selectable for isolated or
non-isolated operation.
Automatic Diagnostics and Fault Identification
The microprocessor based controller features self-
testing circuitry that continuously checks for problems
that could prevent proper system response. When
power is applied, the microprocessor automatically
tests memory. In the Normal operating mode, it
continuously monitors the input signal from the
sensor/transmitter to ensure proper functioning. In
addition, a “watchdog” timer is maintained to ensure
that the program is running correctly. If a fault should
occur:
— The FAULT LED flashes.
— The digital display identifies the nature of the fault
using an alpha-numeric code. Refer to Table 4 for
an interpretation of the codes.
— The normally energized Fault output is de-ener-
gized.
— The dc current output drops to less than 1 ma.
NOTE
The fault code will be shown for about 2 seconds
out of every 5 seconds. The gas concentration at
the sensor will be displayed during the remaining
time. If more than one fault should occur, the
highest priority fault will be displayed. (Table 4 lists
the faults in order of priority.)
Table 3—Selectable Relay Options
Relay Selectable Selectable Selectable
Normally Normally Latch/
Open/Closed Energized/ Non-Latch
De-Energized
Low Y Y1Y
1
High Y Y1N
2
Auxiliary Y Y1Y
1
Fault Y N3N
4
Y = Yes N = No
1Selectable as a group, not individually 2Latching only
3Normally energized only 4No latching option
Table 4—System Status Codes
Status Condition
F9X Initialization failure. (Subcodes are as follows.)
F91 EPROM sumcheck failure.
F92 System failure during startup - current too high or
too low.
F93 Watchdog timer failure.
F94 RAM failure.
F95 Internal 5 volt power supply failure during startup.
F96 External 24 volt power supply failure during startup.
F97 Controller type invalid. Error in data from RAM.
F98 Watchdog timer reset the controller.
F70 External reset button has been activated for 15
seconds or longer. Self-clearing when button is
released.
F60 External 24 vdc power input is not in the 18 to 32
vdc range.
F50 Internal 5 volt power supply is not in the 4.75 to
5.25 volt range.
F40 Sensor fault (after startup). Input is above 35 ma
or below 2 ma.
F30 Negative zero drift. Sensor input is –9% full scale
or lower.
F2X Calibration error. (Subcodes are as follows.)
F20 General calibration fault, or calibration aborted due
to a higher priority fault.
F21 Time ran out while waiting for the user to apply gas
to the sensor.
F22 Sensor input is too low. The sensor cannot
generate enough offset to get an accurate
calibration. Replace sensor.
F23 Sensor is too sensitive for the controller to read
100% full scale. Replace sensor.
F24 Zero gas level too high, or sensor zero input over
limit.
F10 Sensor reaching end of life. Consider replacing the
sensor within the next two calibration periods.

95-840172.1
An alarm condition will normally over-ride a fault
condition unless the fault condition occurred first.
F10 and F2X will not over-ride an alarm. Faults that
affect the actual function of the controller (F50, F60,
F70, F9X) can impair the ability of the controller to
maintain an alarm output.
All faults automatically reset except the F9X, F20,
and F10 faults. After the fault condition has been
corrected, the fault output automatically switches to
the normal (energized) state, the dc current output
returns to normal, and the FAULT LED turns off.
Clearing F9X faults requires removing operating
power from the controller for approximately one
second.
CAUTION
The fault detection circuitry does not monitor the
operation of external response equipment or the
external wiring to these devices. It is important that
these devices be checked periodically to ensure
that they are operational.
Operating Modes
NOTE
The following section is intended to acquaint the
operator with the basic operation of the controller.
For complete step-by-step programming and
calibration procedures, refer to the corresponding
sections in this manual.
The controller can operate in any of the following
modes. Operating modes other than Normal are
selected by pressing the appropriate pushbutton(s)
located on the controller front panel. See Figure 5.
NORMAL
In the Normal operating mode with no alarm
condition:
— Digital display is on and indicates the sensor input
in ppm.
— Bar graph display reads the same as the digital
display.
— All LEDs are off.
— Alarm outputs are in their normal state (energized
or de-energized as programmed).
— DC current output signal level corresponds to sen-
sor input.
— Fault output is energized.
In the Normal operating mode with a low and/or auxil-
iary alarm condition occurring:
— Digital display and bar graph display indicate the
sensor input in ppm.
POWER-UP
TIME DELAY
NORMAL RESET
< 0.5 SEC. 1.0 SEC.
HOLD RESET
7 SEC.
SET
1.0 SEC. NO
YES
0.5 SEC 9.0 SEC.
BASIC
RESET FORCED RESET
RELEASE
RESET
RELEASE
RESET
RELEASE
RESET
SETPOINT
DISPLAY
HOLD
RESET
HOLD
RESET
HOLD
RESET
SENSOR
REPLACE
SETPOINT
ADJUST
CURRENT
CALIBRATE
RESET
PUSHED WITH
SET?
CALIBRATE
SET*
RESET
*MUST BE PRESSED BEFORE THE ZERO
CALCULATIONS ARE COMPLETED.
C1385
Figure 5—R8471B Controller Flow Chart

95-840182.1
— Low and/or Auxiliary LED flashes.
— Low and/or Auxiliary alarm output changes state.
— DC current output signal level corresponds to sen-
sor input.
— Fault output energized and LED off.
When the signal decreases below the low or auxiliary
setpoint:
— Digital display, bar graph display, and 4 to 20 ma
output continue to track the sensor input.
— With latching operation programmed: No change
to alarm outputs.
— With non-latching operation programmed: Alarm
outputs return to their normal state.
— Low and Auxiliary LEDs are on steady until reset.
In the Normal operating mode and a high alarm con-
dition occurring:
— Same as a low or auxiliary alarm condition, but
High LED and high alarm output are affected.
When the signal decreases below the high alarm set-
point:
— The high alarm is always latching and unaffected
by the latching/non-latching programming for the
low and auxiliary alarms. High LED is on steady
until reset.
In the event of a system fault:
— The normally energized Fault output is de-ener-
gized and the FAULT LED is illuminated.
RESET
The Reset mode is entered by pressing the
RESET button located on the front panel of the
controller. (See Figure 5.) When the RESET button
is momentarily depressed, all LEDs turn off and all
outputs return to their normal condition if no alarms or
faults are occurring (basic reset). When the RESET
button is held for 0.5 second, the LEDs turn off and
the outputs return to their normal condition even if
an alarm or fault condition still exists (forced reset).
Remote reset capability is also provided. (Remote
reset performs a forced reset.)
NOTE
The remote reset performs a reset function only.
It cannot be used for entering other controller
operating modes.
SETPOINT DISPLAY MODE
If the RESET button is held for approximately
one second, the controller enters the Setpoint
Display mode. In this mode, the digital display
sequentially shows the programmed alarm setpoints
and calibration gas concentration. Each value
is displayed for approximately 2 seconds. After
completing the sequence, the controller automatically
returns to the Normal operating mode if the RESET
button is no longer being depressed.
This mode is used only for displaying the setpoints.
Use the “Setpoint Adjust” mode for changing setpoint
and calibration gas values.
CALIBRATE
The R8471B Controller uses a fully automatic
calibration procedure that requires no adjustments
by the operator. The Calibrate mode is entered
by pressing and holding the RESET button until
completion of the “Setpoint Display” sequence
described above (approximately 9 seconds). The
controller performs the Zero adjustments, then signals
the operator when to apply and also when to remove
the calibration gas. Upon completion of a successful
calibration, the controller automatically returns to the
Normal operating mode.
If the operator fails to complete the calibration
procedure, if an error in calibrating occurs, or if a
successful calibration cannot be completed, the
microprocessor will automatically return to the Normal
mode (after 10 minutes or when the gas level drops
below the lowest setpoint) and continue to use the
previous calibration data. A fault indication (“F2X”
status) will be displayed until a reset occurs. If the
microprocessor determines that the sensing element
is approaching the end of its useful life, “F10” will
be indicated on the digital display. Refer to the
“Calibration” section of this manual for complete
information regarding calibration.
While in the Calibrate mode, all controller outputs
are inhibited, the CAL LED is illuminated, and the dc
current output goes to a preset level (adjustable from
0 to 20 ma).

95-840192.1
SENSOR REPLACEMENT
This mode inhibits all controller outputs to allow
replacement of the sensing element without removing
power from the controller. In addition, this mode
automatically sets the factory default values for
sensor calibration. Alarm setpoints and calibration
gas concentration are not affected.
CAUTION
Upon entering the Sensor Replacement mode, all
previously entered sensor calibration information
is lost. Sensor calibration must be performed,
even if the sensing element was not replaced.
To enter the Sensor Replacement mode, either enter
the Calibrate mode as described above and press the
SET button, or hold the RESET button for 7 seconds
while in the power-up time delay. To exit this mode,
press the RESET button. Upon exiting the Sensor
Replacement mode, the controller returns to normal
operation after a time delay (five minutes or as soon
as no alarm setpoints are exceeded).
SETPOINT ADJUST
The Setpoint Adjust mode is entered by depressing
the SET button for approximately one second. In this
mode the alarm setpoints and calibration gas level
are sequentially displayed on the digital display for
approximately five seconds and the corresponding
LED flashes. To change the setpoint, depress the
RESET button to increase the displayed value or the
SET button to decrease the value. If no changes
are made for 5 seconds, the microprocessor
automatically advances to the next setpoint. At
the end of the sequence, the microprocessor
automatically returns to the Normal operating mode.
DC CURRENT OUTPUT CALIBRATION
This mode is used to calibrate the 4 to 20 ma dc
output. To enter this mode, hold the SET button,
then press RESET. First the 0 ppm value (4 ma) is
generated for approximately 7 seconds while the
Low LED flashes. Then the full scale value (20 ma)
is generated while the High LED flashes. Finally the
current output level during calibration is generated
while the CAL LED flashes. The microprocessor
automatically returns to the normal operating mode
at the end of the sequence. Adjustments to the
current output level are made by pressing the RESET
(increase) or SET (decrease) button. This procedure
requires a dc current meter to monitor the actual
controller dc milliampere output.
Section II
System Installation
INSTALLATION
NOTE
The C7064E Sensor is not included in the FMRC
approval.
NOTE
Refer to the sensor manual for complete
information regarding sensor installation.
SENSOR LOCATION
Proper location of the sensor is essential for providing
maximum protection. The formula for determining
the most effective number and placement of sensors
varies depending on the conditions at the job site.
The individual performing the installation must rely
on experience and common sense to determine
the number of sensors needed and the best sensor
locations to adequately protect the area.
The following factors are important and should be
considered for every installation:
1. Since hydrogen sulfide is heavier than air, it will
normally tend to settle near the floor or ground,
unless it is heated, mixed with other gases that
are lighter than air, or prevented from doing so by
air movement.
2. How rapidly will the H2S gas diffuse into the air?
Select a location for the sensor as close as practi-
cal to an anticipated source.
3. Ventilation characteristics of the immediate area
must also be considered. Air movement will
cause the gas to accumulate more heavily in one
area than another. Sensors should be placed
where the most concentrated accumulation of
hydrogen sulfide gas is anticipated. Also con-
sider the fact that some ventilation systems do not
operate continuously.
4. The sensor should be located where it is safe from
potential sources of contamination.
5. The sensor should be pointed down to prevent
the buildup of contaminants on the filter.
6. The sensor must be accessible for testing and
calibration.

95-8401102.1
7. Exposure to excessive heat or vibration can
cause premature failure of electronic devices,
and should be avoided if possible. Shielding
the device from intense sunlight will reduce solar
heating and can increase the life of the unit.
Remember, the finest detection system is of little
value if the H2S gas cannot readily come into contact
with the sensor.
GENERAL WIRING REQUIREMENTS
NOTE
The wiring procedures in this manual are intended
to ensure proper functioning of the device under
normal conditions. However, because of the
many variations in wiring codes and regulations,
total compliance to these ordinances cannot be
guaranteed. Be certain that all wiring complies with
applicable regulations that relate to the installation
of electrical equipment in a hazardous area. If in
doubt, consult a qualified official before wiring the
system.
The use of shielded cable is highly recommended for
wiring the H2S detection system to protect against
interference caused be extraneous electrical “noise”.
In applications where the wiring cable is installed in
conduit, the conduit must not be used for wiring to
other electrical equipment.
Since moisture can be detrimental to electronic
devices, it is important that moisture not be allowed
to come in contact with the electrical connections of
the system. Moisture in the air can become trapped
within sections of conduit. Therefore, the use of
conduit seals is required to prevent damage to
electrical connections caused by condensation within
the conduit.
These seals must be watertight and explosion-proof
and are to be installed even if they are not required
by local wiring codes. A seal must be located as
close to the device as possible. In no case should
this seal be located more than 18 inches (46 cm) from
the device. When an explosion-proof installation is
required, an additional seal may be needed at any
point where the conduit enters a non-hazardous area.
Always observe the requirements of local codes.
When pouring a seal, a fiber filler is required to
assure proper formation of the seal. The seals should
never be poured in temperatures that are below
freezing, since the water in the sealing compound
will freeze and the compound will not dry properly.
Contamination problems can then result when
temperatures rise above the freezing point and the
compound thaws.
The shielding of the cable should be stripped back
to permit the seal to form around the individual leads,
rather than around the outside of the shield. This will
prevent any siphoning action that can occur through
the inside of the shield.
It is recommended that conduit breathers also be
used. In some applications, alternate changes in
temperature and barometric pressure can cause
“breathing”, which allows the entry and circulation
of moist air throughout the conduit. Joints in the
conduit system and its components are seldom tight
enough to prevent this “breathing.” Moisture in the
air can condense at the base of vertical conduit runs
and equipment enclosures, and can build up over a
period of time. This can be detrimental to electronic
devices. To eliminate this condition, explosion-
proof drains and breathers should be installed to
automatically bleed off accumulated water.
Two wire cable is used for connecting the sensor to
the controller. Two conductor cable with a foil shield
is recommended. The shield of the cable should be
open at the sensor junction box and connected to
earth ground at the controller.
The maximum distance between the sensor
and controller is limited by the resistance of the
connecting wiring, which is a function of the gauge
of the wire being used. Table 5 shows the maximum
wiring distance allowed for a given wire size. If a
sensor/ transmitter assembly is being used, refer
to the transmitter manual for specific instructions.
SENSOR WIRING
1. Determine the best mounting locations for the
sensors by following the previously discussed
guidelines for locating sensors. Whenever prac-
tical, sensors should be placed where they are
easily accessible for calibration.
2. The sensor junction box can be mounted to a wall
or post, or it can be suspended by the conduit.
The junction boxes should be electrically con-
nected to earth ground.
Table 5—Maximum Wiring Distances – Controller to Sensor
Maximum Sensor
Wire Size to Controller
(AWG) Distance
Feet Meters
18 5700 1750
16 9000 2800

95-8401112.1
The sensor must be oriented with the filter pointing
down. Position the junction box with the conduit
connected to the upper opening. The sensor will be
installed in the lower opening on the junction box.
3. Remove the cover from the junction box.
NOTE
Do not apply power to the system with the junction
box cover removed unless the area has been de-
classified.
4. Remove the cap from the sensor housing. See
Figure 6.
5. Remove the sensing element assembly from its
packaging. Determine proper orientation for the
assembly, then carefully plug it into the sensor
housing.
NOTE
Handle the sensing element assembly carefully.
To avoid possible damage, observe the normally
accepted procedures for handling electrostatic
sensitive devices. See form 75-1005 for additional
information.
6. Place the cap back on the sensor housing.
Tighten only until snug. Do not over tighten.
7. Attach the sensor to the junction box. The sen-
sor should be tight to ensure an explosion-proof
installation, however, do not over tighten.
NOTE
Coat the sensor threads with an appropriate
grease to ease installation, and also lubricate the
junction box cover threads to ensure a water-
tight enclosure. The recommended lubricant is a
silicone free polyalphaolefin grease, part number
005003-001, available from Detector Electronics.
8. Connect the sensor wires to the terminal block
marked “to sensor.” (See Figure 7.) Connect the
controller wiring to the terminal block marked “to
controller.” Connect the shield to earth ground at
the controller. Under normal conditions, the other
end of the shield should not be connected at the
sensor junction box unless such a connection is
required by local wiring codes.
The wiring code is:
Red lead = “+”
Black lead = “–”
Green lead = Chassis (earth) ground.
In order to maintain the intrinsically safe rating of the
C7064C Sensor, it must be wired through an approved
I.S. barrier. See Figure 8.
NOTE
When an I.S. barrier is used, the input voltage
(measured at the controller) must be between 23
and 26.6 vdc to ensure proper operation of the
sensor and barrier.
B1203
SENSOR HOUSING
SENSING ELEMENT ASSEMBLY
CAP
HYDROPHOBIC FILTER
Figure 6—Exploded View of Sensor

95-8401122.1
9. Check the sensor wiring to ensure proper connec-
tions, then pour the conduit seals and allow them
to dry (if conduit is being used).
10. Place the cover back on the junction box.
CONTROLLER WIRING
NOTE
The controller contains semiconductor devices
that are susceptible to damage by electrostatic
discharge. An electrostatic charge can build
up on the skin and discharge when an object is
touched. Therefore, use caution when handling,
taking care not to touch the terminals or electronic
components. For more information on proper
handling, refer to Service Memo form 75-1005.
Field Wiring Connector
The controller is furnished with a field wiring
connector backplate that incorporates pressure type
screw terminals for connecting the external wiring
and a circuit board edge connector for attaching
to the controller. The use of a mounting rack is
recommended for mounting the controller. The
backplate is attached to the back of the rack to allow
easy removal of the controller without disturbing the
wiring. See Figures 9 and 10.
The controller is designed for installation in a non-haz-
ardous area.
Figure 11 shows the terminal configuration for the
R8471B H2S Controller.
Terminals 1 and 2 – 4 to 20 ma dc output.
Non-Isolated Current Output -
If the 4 to 20 ma current loop
is to be non-isolated, wire the
current loop as shown in Figure
12. Note that terminal 2 is not
used with a non-isolated current
loop. Program the controller
for a non-isolated current loop
as described in the “Controller
Programming” section of this
manual.
Isolated Current Output - If an
isolated current loop is desired,
wire the current loop as shown
in Figure 13 and program the
controller for an isolated cur-
rent loop as described in the
“Controller Programming” sec-
tion of this manual. Note that
this wiring scheme requires an
external power source for the
isolated current output.
CURRENT OUTPUT
CHASSIS GROUND
POWER
SENSOR
EXTERNAL RESET
HIGH ALARM
HIGH ALARM / OC
AUX. ALARM
AUX. ALARM / OC
LOW ALARM
LOW ALARM / OC
FAULT
FAULT / OC
1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
–
+
+
–
+
–
18 TO 32
VDC
POWER
SIGNAL
24
VDC*
+
–
C7064C
SENSOR
2
A1704
R8471B CONTROLLER
BLK
RED
GREEN
+
–
MTL 787S
OR
MTL 788
OC = OPEN COLLECTOR OUTPUT
(BASE MODEL ONLY)
*WHEN USING AN I. S. BARRIER,
INPUT VOLTAGE MUST BE 23 TO 26.6 VDC.
Figure 8—R8471B Controller and C7064C Sensor
Used with I.S. Barrier
SENSOR
GROUND
BLK (–) TO TERMINAL 7
RED (+) TO TERMINAL 6
WIRING TO CONTROLLER
GROUND JUNCTION BOX
ACCORDING TO LOCAL CODES
B1528
RED
BLK
GRN
=
=
=
+
–
GROUND
FIBER FILLER
SEALING COMPOUIND
Figure 7—Sensor Wiring

95-8401132.1
Figure 10—Clip Positioning for Q4003 and Q4004 Mounting Racks
Figure 9—Dimensions of the Q4003 and Q4004 Mounting Racks
(A)
(B)
(C)
1.48 (37.59)
(D)
B1475
ALL CONTROLLER CAGES REQUIRE
A MINIMUM OF 10.12 INCHES (257.1 MM)
DEPTH CLEARANCE
(E)
1
A1476
FIRE CONTROLLERS ARE APPROX. TWO INCHES
WIDE AND REQUIRE TWO GUIDE RAILS FOR
INSERTION. PLACE THE RETAINING CLIP BETWEEN
RAILS TO FORM SETS, LEAVE A GAP BETWEEN SETS.
SET SETGAP
123 2
THE Q4004 CONTROLLER CAGE HAS BEEN MODIFIED
TO ACCOMMODATE EITHER FIRE OR GAS CONTROLLERS
OR ANY COMBINATION OF THE TWO.
BY FOLLOWING THE INSTRUCTIONS BELOW, THE CAGE
CAN BE SET UP TO ANY CONFIGURATION.
2TO INSERT A BLANK PANEL, PLACE A CLIP IN
THE TOP BRACKET IN LINE WITH THE CLIP IN THE
BOTTOM BRACKET.
3
GAS CONTROLLERS ARE APPROX. ONE INCH WIDE
AND REQUIRE ONE RAIL FOR INSERTION. PLACE CLIPS
IN LINE WITH GUIDE RAILS, CAGES WILL ACCEPT AS
MANY GAS CONTROLLERS AS RAILS PROVIDED.
CONTROLLER
POSITIONS FOR: HT: DIM. (A) DIM. (B) DIM. (C) DIM. (D) DIM. (E)
FIRE GAS INCH MM INCH MM INCH MM INCH MM INCH MM
8 16 4U 19.00 482.6 18.30 464.8 17.36 440.9 4.00 101.6 6.97 177.1
6 12 4U 15.06 382.6 14.36 364.7 13.42 340.9
4 8 4U 11.13 282.6 10.43 264.9 9.49 241.1
3 6 4U 9.16 232.7 8.46 214.9 7.52 191.0
2 4 4U 7.19 182.7 6.49 164.9 5.55 141.0
1 2 4U 5.22 132.6 4.52 114.8 3.58 90.9
16 3U 19.00 482.6 18.30 464.8 17.36 440.9 2.25 57.15 5.22 132.6
12 3U 15.06 382.6 14.36 364.7 13.42 340.9
8 3U 11.13 282.6 10.43 264.9 9.49 241.1
6 3U 9.16 232.7 8.46 214.9 7.52 191.0
4 3U 7.19 182.7 6.49 164.9 5.55 141.0
2 3U 5.22 132.6 4.52 114.8 3.58 90.9

95-8401142.1
Terminal 3 – Chassis ground. Ground the
cable shield at this terminal.
NOTE
If local wiring codes permit and if a ground fault
monitoring system is not being used, the minus
side of the dc power source can be connected
to chassis (earth) ground. Alternatively, a 0.47
microfarad, 100 volt capacitor can be installed
(terminal 5 to ground) for best immunity against
electromagnetic interference.
Terminal 4 – Connect to the positive (+)
side of the 18 to 32 vdc power
source.
Terminal 5 – Connect to the negative (–) side
of the dc power source.
Terminal 6 – Connect to the red (+) lead of
the sensor. If a separate trans-
mitter is used, no connections
are made to this terminal.
Terminal 7 – Connect to the black (–) lead of
the sensor or the 4 to 20 ma dc
signal input from the transmitter/
sensor assembly.
Terminal 8 – A normally open momentary clo-
sure switch can be connected
between this terminal and the
negative (–) side of the power
source for remote reset.
Terminals 9 and 10 – High Alarm Output.
Terminals 11 and 12 – Auxiliary Alarm Output.
Terminals 13 and 14 – Low Alarm Output.
Terminals 15 and 16 – Fault Output.
Figure 12—A Typical System – R8471B with Relay Outputs, Non-
Isolated Current Output and C7064E Sensor
CURRENT OUTPUT
CHASSIS GROUND
POWER
SENSOR
EXTERNAL RESET
HIGH ALARM
HIGH ALARM / OC
AUX. ALARM
AUX. ALARM / OC
LOW ALARM
LOW ALARM / OC
FAULT
FAULT / OC
1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
–
+
+
–
+
–
18 TO 32
VDC
POWER
SIGNAL
2
OC = OPEN COLLECTOR OUTPUT
(BASE MODEL ONLY) B1390
Figure 11—Terminal Configuration for the R8471B
H2S Controller
CURRENT OUTPUT
CHASSIS GROUND
POWER
SENSOR
EXTERNAL RESET
HIGH ALARM
HIGH ALARM / OC
AUX. ALARM
AUX. ALARM / OC
LOW ALARM
LOW ALARM / OC
FAULT
FAULT / OC
1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
–
+
+
–
+
–
18 TO 32
VDC
POWER
SIGNAL
HIGH
ALARM
AUXILIARY
ALARM
LOW
ALARM
FAULT
RESET
24 VDC
+
–
C7064E
2
A1427
R8471B CONTROLLER
4 TO 20 MA
BLK
RED
GREEN
+–
CURRENT OUTPUT
CHASSIS GROUND
POWER
SENSOR
EXTERNAL RESET
HIGH ALARM
HIGH ALARM / OC
AUX. ALARM
AUX. ALARM / OC
LOW ALARM
LOW ALARM / OC
FAULT
FAULT / OC
1
3
4
5
6
7
8
9
10
11
12
13
14
15
16
–
+
+
–
+
–
18 TO 32
VDC
POWER
SIGNAL
HIGH
ALARM
AUXILIARY
ALARM
LOW
ALARM
FAULT
RESET
+
–
SIG
TRANSMITTER
SENSOR
2
4 TO 20 MA
A1428
R8471 CONTROLLER
*
*NO CONNECTION
+–
24 VDC
+
–
24 VDC
+
–
Figure 13—A Typical System - R8471B with Relay Outputs,
Isolated Current Output and Optional Transmitter

95-8401152.1
PREMIUM CONTROLLER
The relay outputs (terminals 9 to 16) are programmed
for the desired operation using the procedure
described in the “Controller Programming” section of
this manual.
BASE CONTROLLER
Connections to open collector transistor outputs are
made at terminals 10, 12, 14, and 16. Terminals 9,
11, 13, and 15 are not used. See Figure 14 for an
example of a typical connection to an open collector
transistor output.
NOTE
External equipment that can generate transients
when switching (such as relays) must have a
transient suppression device (diode) properly
connected across the coil at the time of installation.
This will safeguard the output transistors of the
controller against possible damage. Figure 14
illustrates an inductive load with a diode used for
transient suppression.
CONTROLLER PROGRAMMING
Refer to Figure 15 to determine the location of
programming jumpers and switches. Table 3 shows
the selectable options for each relay.
NOTE
All jumper plugs must be installed. The controller
outputs will not function properly if a jumper plug is
missing.
Normally Open/Closed Relays
The four SPST relays are individually programmed
for either normally open or normally closed contacts.
This is accomplished by placing a jumper plug on
the appropriate pair of pins. Each relay has a set of
three pins. For normally open operation, place the
plug on the NO and center pins. For normally closed
operation, place it on the NC and center pins. The
pin groups are identified as follows:
J2 – High Alarm
J3 – Auxiliary Alarm
J4 – Low Alarm
J5 – Fault
The controller is programmed at the factory for nor-
mally open relay contacts.
NOTE
“Normally Open” or “Normally Closed” refers to
the condition of the relay contacts when “Normally
de-energized” operation is selected. (Refer to
the setting of SW1-2 below.) If the relays are
“Normally Energized,” the condition of the relay
contacts will be reversed.
Latching/Non-Latching Relays
The Low and Auxiliary alarm relays are programmable
for latching or non-latching operation. The High alarm
relay is always latching. Latching relay operation is
programmed using rocker switch 1 at SW1 (SW1-1).
For latching operation, place the switch in the closed
position. For non-latching operation, place it in the
open position. This switch is set at the factory for
non-latching relay operation.
Normally Energized/De-Energized Relays
The three alarm relays are also programmable
for normally energized (fail-safe) or normally de-
energized operation. This is accomplished by
setting rocker switch 2 at SW1 (SW1-2). For normally
energized alarm relays, place the switch in the closed
position. For normally de-energized operation, place
it in the open position. This switch is set at the factory
for normally de-energized operation.
The Fault relay is always normally energized,
regardless of the setting of SW1-2.
NOTE
If the switch positions of SW1 are changed while
power is applied, power must be cycled for the
change to take effect.
4 to 20 ma Output
Isolated or non-isolated operation of the 4 to 20 ma
output is selected using a jumper plug at J1. For non-
isolated operation, as illustrated in Figure 12, place
the jumper plug in the INT (internal power source)
position. Place the plug in the EXT position for an
isolated circuit, as illustrated in Figure 13. The jumper
is set at the factory for non-isolated operation.
100K
OPEN COLLECTOR OUTPUT
1N4004
TYPICAL
+32 VDC MAXIMUM
B1289
Figure 14—Open Collector Output with Inductive Load and
Transient Suppression Device

95-8401162.1
INSTALLATION CHECKLIST
The following checklist is provided as a means of
double checking the system to be sure that all phases
of system installation are complete and have been
performed correctly.
1. Sensors are pointing down and junction boxes are
securely mounted.
2. All cable shields are properly grounded.
3. All junction box covers are tightly installed.
4. Explosion-proof conduit seals have been installed
at all junction box entries (if conduit is being
used).
5. Sensor to controller wiring is correct.
6. Power wiring to the controller is installed and
power source is operational.
7. External loads are properly connected to the con-
troller.
8. Controller is programmed as desired. Record this
information for future reference.
9. Controller is properly installed in the mounting
rack.
10. Proper ventilation is provided to prevent over-
heating of the controller.
Proceed to System Startup, Setpoint Adjustment, and
Calibration.
Section III
System Startup
STARTUP PROCEDURE
1. Output loads that are normally actuated by the
system should be secured (remove power from all
output devices) to prevent undesired activation.
2. Check all external wiring for proper connection.
Be sure that the sensor has been wired properly.
3. Before installing the controller in the mounting
rack, inspect it to verify that it has not been physi-
cally damaged in shipment. Check the jumper
plugs and rocker switches on the controller for
proper programming, then slide the controller fully
into the mounting rack.
4. Apply power to the system.
Figure 15—Programming Jumper Plugs and Switches
A1392
HIGH ALARM
SW1-1 CLOSED = LATCHING
OPEN = NON-LATCHING
SW1-2 CLOSED = NORMALLY ENERGIZED
OPEN = NORMALLY DE-ENERGIZED
LOW ALARM
FAULT
AUXILLIARY ALARM
NORMALLY
OPEN/CLOSED
RELAY CONTACTS
J1 INT = NON-ISOLATED
EXT = ISOLATED

95-8401172.1
NOTE
The controller has a power-up time delay to allow
the sensor output to stabilize before beginning
normal operation. During this time the outputs
are inhibited, the FAULT LED is illuminated, and
the current output indicates a fault condition.
The controller automatically exits the time delay
mode after 5 minutes have elapsed or as soon as
the sensor output no longer exceeds any alarm
setpoints.
5. Put the controller in the Setpoint Display mode
to determine the present alarm setpoints and
calibration gas concentration. If changes are
required, perform the Setpoint Adjustment proce-
dure.
6. Perform the calibration procedure.
7. Check the 4 to 20 ma current loop for proper cali-
bration and adjust as required.
8. Remove mechanical blocking devices (if used)
and restore power to the output loads.
SETPOINT ADJUSTMENT
The adjustment range in ppm for the alarm setpoints
and calibration gas concentration is as follows:
The factory settings in ppm are:
To check the present levels, use the “Setpoint Display
Mode” described below. To change the values, use
the “Setpoint Adjustment Procedure.”
SETPOINT DISPLAY MODE
1. To enter the Setpoint Display mode, press and
hold the RESET button until the Low LED begins
to blink (approximately one second). Release
the RESET button. The low alarm setpoint will be
shown for two seconds on the digital display.
NOTE
The RESET button should be released as soon
as the controller has entered the Setpoint Display
mode (after one second). If the button is still
depressed at the end of the Setpoint Display mode
(9 seconds), the controller will automatically enter
the Calibrate mode. If the operator is not prepared
to perform a calibration, a calibration fault will
occur. Recycle power to the controller to exit the
Calibrate mode without affecting the calibration
settings.
2. At the end of the two second interval, the Low
LED goes out, the High LED begins to blink, and
the digital display shows the high alarm setpoint.
3. Two seconds later the High LED goes out and
the Auxiliary LED blinks. The digital display now
shows the programmed auxiliary alarm setpoint.
4. Two seconds later the Auxiliary LED goes out
and the CAL LED blinks. The digital display now
shows the programmed calibration gas concen-
tration.
5. After displaying the calibration gas concentra-
tion for two seconds, the controller automatically
leaves the Setpoint Display mode and returns to
the Normal operating mode.
6. If adjustments to the setpoints are required, per-
form the Setpoint Adjustment procedure. When
the setpoint levels are acceptable, record this
information for future reference and perform the
Calibration procedure.
SETPOINT ADJUSTMENT PROCEDURE
1. Determine the required alarm setpoint levels and
calibration gas concentration.
2. Press and hold the SET button for one second.
The digital display indicates the present low
alarm setpoint and the Low LED blinks. Press the
RESET button to increase the reading or the SET
button to decrease the reading. (Holding the but-
ton will cause the reading to change rapidly.)
3. When no changes to the setpoint level have been
made for 5 seconds, the Low LED goes out, the
High LED blinks, and the digital display shows the
high alarm setpoint. Press the appropriate button
(detailed in step 2 above) to obtain the desired
reading on the digital display.
4. When no changes to the setpoint level have been
made for 5 seconds, the High LED goes out, the
Auxiliary LED blinks, and the digital display shows
Range: 0 to 100 0 to 50 0 to 20
Low alarm: 5 to 40 1 to 25 0.5 to 10
High alarm: 10 to 60 2 to 45 1 to 18
Aux. alarm: 5 to 99 1 to 45 0.5 to 18
Cal. gas: 30 to 99 15 to 45 6 to 18
Range: 0 to 100 0 to 50 0 to 20
Low alarm: 10 5 2
High alarm: 20 10 4
Aux. alarm: 20 10 4
Cal. gas: 50 25 10

95-8401182.1
the auxiliary alarm setpoint. Press the appropriate
button to obtain the desired reading on the digital
display.
5. When no changes have been made for 5 sec-
onds, the Auxiliary LED goes out, the CAL LED
blinks, and the digital display indicates the cali-
bration gas concentration. Press the appropriate
button to change the calibration gas concentra-
tion as required.
6. When no changes have been made for 5 sec-
onds, the controller automatically returns to the
Normal operating mode.
7. Record the new values for future reference.
NOTE
The alarm setpoints, calibration gas concentration,
and calibration data are stored in non-volatile
memory and are retained in the event of a power
loss. However, if power is interrupted while
performing the Setpoint Adjustment or Calibration
procedure, the entire procedure must be repeated
when power is restored.
CALIBRATION
Various factors affect the time interval between
periodic recalibrations. Exposure to certain
contaminants in the air, accumulation of contaminants
on the filter, or an extended period of normal
operation can cause changes in sensitivity. Since
each application is different, the length of time
between regularly scheduled recalibrations can
vary from one installation to the next. In general, the
more frequently a system is checked, the greater the
reliability. Calibration must be performed:
—When a new system is initially put into service
—When the sensing element is replaced
—If a transmitter or controller used in conjunction with
the sensor is replaced
—When the hydrophobic filter is cleaned or replaced.
The following calibration schedule is recommended
when placing a new sensor into operation and will
ensure reliable operation in most applications:
1. One hour after power-up
2. One week later
3. Every 30 days thereafter, or as determined by the
needs of the specific application.
IMPORTANT
To ensure adequate protection, the H2S detection
system must be calibrated on a regularly
scheduled basis.
Loss of sensitivity can be caused by various fac-
tors. One common cause is by clogging of the
hydrophobic filter by dirt, oil, paint, etc. Problems
of this nature will not be detected by the system’s
diagnostic circuitry. While performing detec-
tor calibration, the operator should examine the
hydrophobic filter of the sensor. If it cannot be
properly cleaned, it should be replaced.
The detector must be calibrated using hydrogen
sulfide mixed with either air or nitrogen. For best
results, a calibration gas concentration equal
to the high alarm setpoint or 50% of full scale is
recommended.
NOTE
If the sensing element is being replaced, refer to
the “Sensing Element Replacement” section (under
“Maintenance”) in this manual for information
regarding replacement and calibration of the
sensor.
CALIBRATION PROCEDURE
The H2S detection system can be calibrated using
either of two methods:
1. Transmitter calibration (if a transmitter is
used). This method of calibration can be per-
formed by one person. All adjustments are made
at the transmitter. Calibration of certain transmit-
ter models requires removing the enclosure cover,
therefore, the hazardous area must be de-classi-
fied.
When transmitter calibration is performed, an
initial calibration of the controller must be per-
formed in addition to the transmitter calibration.
This calibration of the controller is not the same
as “2. Controller Calibration” described below.
It involves setting factory default calibration val-
ues in the controller that will ensure accuracy
when used in conjunction with a properly cali-
brated transmitter. Since these default values do
not change, the procedure does not need to be
repeated with subsequent transmitter recalibra-
tions. This controller calibration is accomplished
by momentarily entering the Sensor Replacement
mode. Upon entering the Sensor Replacement
mode, the controller automatically sets the fac-
tory default controller calibration values. (Follow
the procedure described in the “Setting Controller
Default Values” section.)