Detcon IR-622 User Manual

detcon inc.

™

Detcon MicroSafe

IR-622 Combustible Hydrocarbon Sensor (0-100% LEL)

Operator’s Installation & Instruction Manual

November 26, 2007 • Document #2195 • Version 6.3

CAUTION:

Before operating the Model IR-622 sensor, read this manual thoroughly and verify that the con­figuration of default factory settings are appropriate and correct for your application. The set­tings include: relay contact outputs (section 3.5.5d), alarm settings (section 3.5.5e and 3.9), and
RS-485 ID (section 3.5.5f and 3.12).

Table of Contents

3.0 Description

3.1 Principle of Operation

3.2 Application

3.3 Specifications

3.4 Operating Software

3.5 Installation

3.6 Start-up

3.7 Calibration

3.8 Status of Programming, Alarms, Calibration Level, RS-485 ID, and Sensor Life

3.9 Programming Alarms

3.10 Program Features

3.11 RS-485 Protocol

3.12 Display Contrast Adjust

3.13 Optical Sensor Replacement

3.14 Troubleshooting

3.15 Spare Parts List

3.16 Warranty

3.17 Service Policy

3.18 Software Flow Chart

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.2

3.0 DESCRIPTION

Detcon MicroSafe™ Model IR-622, combustible hydorcarbon gas sensors are non-intrusive “Smart” sensors
designed to detect and monitor combustible hydorcarbon gas in air over the range of 0-100% lower explosive limit
(LEL). One of the primary features of the sensor is its method of automatic calibration which guides the user
through each step via instructions displayed on the backlit LCD. The sensor features field adjustable, fully program­mable alarms and provides relays for two alarms plus fault as standard. The sensor comes with two different out­puts: analog 4-20 mA, and serial RS-485. These outputs allow for greater flexibility in system integration and instal­lation. The microprocessor supervised electronics are packaged as a plug-in module that mates to a standard con­nector board. Both are housed in an explosion proof condulet that includes a glass lens window which allows for
the display of sensor readings as well as access to the sensor’s menu driven features via a hand-held programming
magnet.

The sensor technology is a field proven “plug-in replaceable” non-dispersive infrared (NDIR) optical type. NDIR
optical sensors show an excellent response to a long list of combustible hydrocarbon gases. This technique is non­selective and may be used for the detection and monitoring of many target combustible hydrocarbon gases. As
compared to catalytic bead sensors, with NDIR there is no risk of sensor poisoning, no risk of high concentration
saturation, and no need for O2 to be present. The NDIR type sensor is characteristically stable for both span and
zero and is capable of providing reliable performance with low maintenance requirements for periods approaching
5 years in most industrial environments.

3.0.1 Non-dispersive Infrared (NDIR) Optical Sensor

The Detcon NDIR sensor is designed as a miniature single piece “plug-in replaceable” component, which can easily be
changed out in the field. The NDIR sensor consists of an infrared lamp source, two pyroelectric detectors, and an
optical gas sample cavity. The lamp source produces infrared radiation which interacts with the target gas as it travels
through the optical gas sample cavity. The infrared radiation contacts each of two pyroelectric detectors at the comple­tion of the optical path. The “active” pyroelectric detector is covered by a filter specific to the part of the IR spectrum
where the target gas absorbs light. The “reference” pyroelectric detector is covered by a filter specific to the non­absorbing part of the IR spectrum. When the target gas is present, it absorbs IR radiation and the signal output from
the “active” pyroelectric detector decreases accordingly while the “reference” detector output remains unchanged. The
ratio of the “active” and “reference” detector outputs is then used to compute the target gas concentration.

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.3

3.0.2 Microprocessor Control Circuit

NC

ALARM 1

WHT

BLK

YEL

BLU

MA

VDC Power In

Optional RS-485

Terminating Resistor

Use 120 ohm

NO

NC

NO

NC

NO

NO/NC

COM

NO/NC

COM

NO/NC

COM

FAULT ALM -2 ALM -1

Alarm Dry Contacts

ALARM 2

FAULT

R1

R2

A

B

A

B

4-20 mA Output

RS-485 In

RS-485 Out

Optional 4-20 mA
Signal Developing Resistor
Use 250 ohm 1/4w

JU

M

P

E

R

S

U

N

-U

S

E

D

RED

BRN

Jumper Programmable Alarm Outputs
Normally Open or Normally Closed

Sensor

Place un-used alarm programming
jumper tabs here

detcon inc.

Program Switch #2

FLT

ALM

1

CAL

MicroSafe™ LEL Gas Sensor

HOUS TON, TEX AS

PGM 2

PGM 1

ALM

2

MODEL IR-622

CONTRAST

Alarm & Cal LEDs

Program Switch #1

Menu Driven Display

Plug-in Microprocessor Control Circuit

Display Contrast Adjust

Porous Membrane

Optical Filter

Active Detector

Lamp

Reference Detector

Optical Sample Gas Chamber

H

CHH

H

H

CHH

H

Optical Filter

The control circuit is microprocessor based and is packaged as a plug-in field replaceable module, facilitating easy
replacement and minimum down time. Circuit functions include a basic sensor pre-amplifier, sensor temperature
measurement, on-board power supplies, microprocessor, back lit alpha numeric display, alarm status LED indica­tors, magnetic programming switches, an RS-485 communication port, and a linear 4-20 mA DC output.

3.0.3 Base Connector Board

The base connector board is mounted in the explosion proof enclosure and includes: the mating connector for the
control circuit, reverse input and secondary transient suppression, input filter, alarm relays, lugless terminals for all
field wiring, and a terminal strip for storing unused programming jumper tabs. The alarm relays are contact rated 5
amps @ 250 VAC, 5 amps @ 30 VDC and coil rated at 24 VDC. Gold plated program jumpers are used to select
either the normally open or normally closed relay contacts.

3.0.4 Explosion Proof Enclosure

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.4

The sensors are packaged in a cast metal explosion proof enclosure. The enclosure is fitted with a threaded cover

IR Lamp Source

Reference Detector Output

Active Detector Output

Target Gas Not Present

Gas Present

Principle of Operation

Sample

Gas

that has a glass lens window. Magnetic program switches located behind the transmitter module face plate are acti­vated through the lens window via a hand-held magnetic programming tool allowing non-intrusive operator inter­face with the sensor. All calibration and alarm level adjustments can be accomplished without removing the cover
or declassifying the area. Electrical classification is Class I; Groups B, C, D; Div. 1.

3.1 PRINCIPLE OF OPERATION

The target gas diffuses through a sintered stainless steel flame arrestor and into the volume of the sample gas opti­cal cavity. A lamp source provides a cyclical IR radiation source which travels through the optical gas sample cavity
and terminates at two pyroelectric detectors. The “active” and “reference” pyroelectric detectors each give an output
which measures the intensity of the radiation contacting their surface. The “active” pyroelectric detector is covered
by an optical filter specific to the part of the IR spectrum where the target gas absorbs light. The “reference” pyro­electric detector is covered by a filter specific to the non-absorbing part of the IR spectrum. When present, the tar­get gas absorbs a fraction of the IR radiation and the signal output from the “active” pyroelectric detector decreases
accordingly. The signal output of the “reference” detector remains unchanged in the presence of the target gas. The
ratio of the “active” and “reference” detector signal outputs is then used to compute the target gas concentration.
By using the ratio of the active/reference signal outputs, measurement drift caused by changes in the intensity of
the lamp source and changes in the optical path are negated.

3.1.2 Characteristics

The NDIR optical sensor element maintains strong sensitivity to combustible hydrocarbon gases in air in the lower explo-

sive range (0-100% LEL), as shown in the illustration below. When compared with the typical catalytic bead LEL sensor,
the NDIR sensor exhibits excellent long-term zero and span stability. Typical zero calibration intervals would be monthly
to quarterly and typical span calibration intervals would be semi-annual to annual. However, actual field experience is
always the best determination of appropriate calibration intervals.

NOTE:

The IR-622 detector will not respond to combustible gases such as H2, NH3, CO, etc, which are not hydrocarbons.

The MicroSafe™ IR-622 is factory calibrated for a specific target gas. Unless otherwise specified, the detector will be factory
calibrated for methane service. If a combustible hydrocarbon gas other than methane is being measured, contact Detcon for
the appropriate field-replaceable electronics/software upgrade.

The NDIR optical sensor readings can be adversely affected by dust, dirt and oil mist accumulation as well as severe corro-

sion. These deposits may reduce the optical reflectivity inside the sensor, and although accurate readings are continually main-

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.5

tained, excessive loss in useable signal eventually gives way to noise and unstable readings. The optical sensor may, over long

Functional

Block

Diagram

Functional

Block

Diagram

Analog 4-20 mA Out

Power In

R

elays Out

P

re-Amp Display

T

emperature

Compensation

A

larm & Fault

Relays

RS-485 & 4-20mA

M

icro-

processor

Tran smit ter

Power Supply

Optical
Sensor

I/O Circuit
Protection

Serial RS-485 Out

0

4

8

12

16

20

20 40 60 80 100

mA DC Signal Output

Output Response Curve

periods of time (3-7 years), lose its IR lamp source filament, and in this case an optical sensor modular replacement is
required. The IR-622 has an extensive list of Fault Diagnostics to alert and pin-point operational problems. See section 3.10

3.2 APPLICATION

Model IR-622 MicroSafe™ sensors are designed to detect and monitor combustible hydrocarbon gas in ambient air in
the range of 0-100% LEL. Minimum sensitivity and scale resolution is 1%. Operating temperature range is -40° F. to
+175° F. While the sensor is capable of operating outside these temperatures, performance specifications are verified
within the limit.

3.2.1 Sensor Placement/Mounting

Sensor location should be reviewed by facility engineering and safety personnel. Area leak sources and perimeter mounting
are typically used to determine number and location of sensors. The sensors are generally located 2 - 4 feet above grade.

3.2.2 Response to Different Gases

The MicroSafe™ IR-622 responds to all combustible hydrocarbon gases, but at different signal strengths. In order to maintain
accurate readings, the detector must be calibrated to the specific target gas of interest.

The MicroSafe™ IR-622 is factory calibrated for the specific target gas chosen at the time of order. Unless otherwise speci­fied by the customer, the detector will be factory calibrated for methane service. Once installed in the field, if a combustible
hydrocarbon gas other than the gas specified at the time of order is being measured, contact Detcon for the appropriate field­replaceable electronics/software upgrade. The calibration gas used to span the IR-622 must be the same gas type as the target
gas being measured.

3.3 SPECIFICATIONS

Method of Detection

NDIR Optical

Electrical Classification

Class I; Groups B, C, D; Div. 1.

Response Time

T50 < 15 seconds; T90 < 35 seconds

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.6

Clearing Time

90% < 35 seconds

epeatability

R

± 3% FS

Range

0-100% (lower explosive limit) LEL

Operating Temperature

-40° to +175° F

Accuracy

± 3% FS

Sensor Warranty

5 year pro-rated

Power Consumption

Normal operation = 95 mA (2.3 watts); Full alarm = 123 mA (<3 watts)

Zero Drift

< 5% per year

Output

3 relays (alarm 1, alarm 2, and fault) contact rated 5 amps @ 250 VAC, 5 amps @ 30 VDC;
Linear 4-20 mA DC; RS-485 Modbus™

Input Voltage

22.5-28 VDC

3.4 OPERATING SOFTWARE

Operating software is menu listed with operator interface via the two magnetic program switches located under the
face plate. The two switches are referred to as “PGM 1” and “PGM 2”. The menu list consists of 3 items which
include sub-menus as indicated below. (Note: see the last page of this manual for a complete software f low chart.)

01. Normal Operation

a) Current Status

02. Calibration Mode

a) Zero
b) Span

03. Program Menu

a) Program Status
b) Alarm 1 Level
c) Alarm 2 Level
d) Calibration Level

3.4.1 Normal Operation

In normal operation, the display tracks the current status of the sensor and gas concentration and appears as:
“0 % LEL”. The mA current output corresponds to the monitoring level and range of 0-100% = 4-20 mA.

3.4.2 Calibration Mode

Calibration mode allows for sensor zero and span adjustments. “1-ZERO 2-SPAN”

3.4.2.1 Zero Adjustment

Zero is set in ambient air with no combustible gas present or with zero gas applied to the sensor. “AUTO ZERO”

3.4.2.2 Span Adjustment

Unless otherwise specified, span adjustment is performed at 50% LEL methane in air. “AUTO SPAN”

3.4.3 Program Mode

The program mode provides a program status menu, allows for the adjustment of alarm set point levels, and the
selection of the calibration gas level setting..

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.7

3.4.3.1 Program Status

The program status scrolls through a menu that displays:
* The gas type, range of detection and software version number. The menu item appears as: “LEL 0-100 V6.0”
* The alarm set point level of alarm 1. The menu item appears as: “ALM1 SET @ ##%”
* The alarm firing direction of alarm 1. The menu item appears as: “ALM1 ASCENDING” or descending.
* The alarm relay latch mode of alarm 1. The menu item appears as: “ALM1 NONLATCHING” or latching.
* The alarm relay energize state of alarm 1. The menu item appears as: “ALM1 DE-ENERGIZED” or energized.
* The alarm set point level of alarm 2. The menu item appears as: “ALM2 SET @ ##%”
* The alarm firing direction of alarm 2. The menu item appears as: “ALM2 ASCENDING” or descending.
* The alarm relay latch mode of alarm 2. The menu item appears as: “ALM2 LATCHING” or nonlatching.
* The alarm relay energize state of alarm 2. The menu item appears as: “ALM2 DE-ENERGIZED” or energized.
* The alarm relay latch mode of the fault alarm. The menu item appears as: “FLT NONLATCHING” or latching.
* The alarm relay energize state of the fault alarm. The menu item appears as: “FLT ENERGIZED” or deenergized.
* The calibration gas level setting. The menu item appears as: “CalLevel @ xx%”
* Identification of the RS-485 ID number setting. The menu item appears as: “485 ID SET @ ##”
* Sensor temperature in °C appears as: “TEMPERATURE xx °C”
* The estimated remaining sensor life. The menu item appears as: “OPTICS AT 100%”

3.4.3.2 Alarm 1 Level Adjustment

The alarm 1 level is adjustable over the range 10 to 90%. For combustible gas sensors, the level is factory set at
20%. The menu item appears as: “SET ALM1 @ 20%”

3.4.3.3 Alarm 2 Level Adjustment

The alarm 2 level is also adjustable over the range 10 to 90%. For combustible gas sensors, the level is factory set at
60%. The menu item appears as: “SET ALM2 @ 60%”

3.4.3.4 Calibration Level Adjustment

The Calibration level is adjustable from 10% to 90% LEL. The menu item appears as: “CalLevel @ ##%”

3.5 INSTALLATION

Optimum performance of ambient air/gas sensor devices is directly relative to proper location and installation practice.

3.5.1 Field Wiring Table

Detcon Model IR-622 combustible gas sensor assemblies require three conductor connection between power sup­plies and host electronic controllers. Wiring designators are
single conductor resistance between sensor and controller is 10 ohms. Maximum wire size for termination in the
sensor assembly terminal board is 14 gauge.

AWG Meters Feet

20 240 800
18 360 1200
16 600 2000
14 900 3000

Note 1:

Note 2: Shielded cable may be required in installations where cable trays or conduit runs include high voltage

lines or other sources of induced interference.

Note 3: The supply of power must be from an isolating source with over-current protection as follows:

AWG

22 3A 16 10A
20 5A 14 20A

18 7A 12 25A
The RS-485 (if applicable) requires 24 gauge, two conductor, shielded, twisted pair cable between sensor and host
PC. Use Belden part number 9841. Two sets of terminals are located on the connector board to facilitate serial loop
wiring from sensor to sensor. Wiring designators are

This wiring table is based on stranded tinned copper wire and is designed to serve as a reference only.

Over-current Protection AWG Over-current Protection

(4-20 mA output)

A& B

+

(DC), –(DC) , and mA(sensor signal). Maximum

(IN) and A& B(OUT).

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.8

3.5.2 Sensor Location

EYS

Seal

Fitting

Drain

“T”

Plug any unused ports.

Selection of sensor location is critical to the overall safe performance of the product. Five factors play an important
role in selection of sensor locations:

(1) Density of the gas to be detected
(2) Most probable leak sources within the industrial process
(3) Ventilation or prevailing wind conditions
(4) Personnel exposure
(5) Accessibility for routine maintenance

Density

- Placement of sensors relative to the density of the target gas is such that sensors for the detection of
heavier than air gases should be located within 2-4 feet of grade as these heavy gases will tend to settle in low lying
areas. For gases lighter than air, sensor placement should be 4-8 feet above grade in open areas or in pitched areas
of enclosed spaces.

Leak Sources

- Most probable leak sources within an industrial process include f langes, valves, and tubing connec­tions of the sealed type where seals may either fail or wear. Other leak sources are best determined by facility engi­neers with experience in similar processes.

Ventilation

- Normal ventilation or prevailing wind conditions can dictate efficient location of gas sensors in a

manner where the migration of gas clouds is quickly detected.

Personnel Exposure

- The undetected migration of gas clouds should not be allowed to approach concentrated per­sonnel areas such as control rooms, maintenance or warehouse buildings. A more general and applicable thought
toward selecting sensor location is combining leak source and perimeter protection in the best possible configuration.

Note:

In all installations, the sensor element in SS housing points down relative to grade (Fig. 1). Improper sensor

orientation may result in false reading and permanent sensor damage.

3.5.3 Local Electrical Codes

Sensor and transmitter assemblies should be installed in accordance with all local electrical codes. Use appropriate

Figure #1

conduit seals. Drains & breathers are recommended. The sensor assemblies are designed to meet NEC and CSA
requirements for Class I; Groups B, C, D; Div. 1 environments.

3.5.4 Accessibility

Consideration should be given to easy access by maintenance personnel as well as the consequences of close prox­imity to contaminants that may foul the sensor prematurely.

Note:

EYD2 or equivalent are suitable for this purpose.

3.5.5 Installation Procedure

Note: See section 3.5.6 for special information on remote mounting applications in which the sensor (Model IR­622-RS) is remotely mounted away from the transmitter (Model IR-622-RT).

An appropriate conduit seal must be located within 18" of the sensor assembly. Crouse Hinds type EYS2,

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.9

a) Remove the junction box cover and un-plug the control circuit by grasping the two thumb screws and pulling outward.

NC

ALARM 1

WHT

BLK

YEL

BLU

MA

VDC Power In

Optional RS-485

Terminating Resistor

Use 120 ohm

NO

NC

NO

NC

NO

NO/NC

COM

NO/NC

COM

NO/NC

COM

FAULT ALM-2 AL M-1

Alarm Dry Contacts

ALARM 2

FAULT

R1

R2

A

B

A

B

4-20 mA Output

RS-485 In

RS-485 Out

Optional 4-20 mA
Signal Developing Resistor
Use 250 ohm 1/4w

JUMPERS

UN-USED

RED

BRN

Jumper Programmable Alarm Outputs
Normally Open or Normally Closed

Sensor

Place un-used alarm programming
jumper tabs here

4

3/4"

3/4" NPT

1/4" Dia.

Mounting Holes

8 1/4"

6

1/8"

5

1/2"

3/4" NPT

Rainshield/

Splashguard

2

"

2 1/8"

b) Securely mount the sensor junction box in accordance with recommended practice. See dimensional drawing (Fig. 2).
c) Observing correct polarity, terminate 3 conductor field wiring, RS-485 wiring, and applicable alarm wiring to the

sensor base connector board in accordance with the detail shown in Figure 3. Normally open and normally closed
Form C dry contacts (rated 5 amp @ 120VAC; 5 amp @ 30VDC) are provided for Fault, Alarm 1, and Alarm 2.

Figure #2

Note:

Per U.L. approval, these relays may only be used in connecting to devices that are powerd by the

voltages.

d) Position gold plated jumper tabs located on the connector board in accordance with desired Form C dry con-

tact outputs: NO = Normally Open; NC = Normally closed (see figure 3).

Note

: If a voltage signal output is desired in place of the 4-20mA output, a 1/4 watt resistor must be installed
in position R2 of the terminal board. A 250Ω resistor will provide a 1-5V output (– to mA). A 100Ω resistor will
provide a .4-2V output, etc. This linear signal corresponds to 0-100% of scale (see figure 3).

e) Program the alarms via the gold plated jumper tab positions located on the CPU board (see figure 4). Alarm 1

and Alarm 2 have three jumper programmable functions: latching/non-latching relays, normally energized/nor­mally de-energized relays, and ascending/descending alarm set points. The fault alarm has two jumper program­mable functions: latching/non-latching relay, and normally energized/normally de-energized relay. The default

Figure #3

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.10

same

settings of the alarms (jumpers removed) are normally de-energized relays, non-latching relays, and alarm points

Preamp Board - Side View

RS-485 ID Set Dip Switches

Control Circuit - Side View

Preamp Board

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

SW2SW1

FAULT

ALARM 1

Latch

Energize

Latch

Ascending

Energize

ALARM 2

Latch

Ascending

Energize

CPU Board - Top View

Alarm Programming Jumpers

Control Circuit - Side View

CPU Board

that activate during descending gas conditions.

If a jumper tab is installed in the latch position, that alarm relay will be in the latching mode. The latching
mode will latch the alarm after alarm conditions have cleared until the alarm reset function is activated. The non­latching mode (jumper removed) will allow alarms to de-activate automatically once alarm conditions have cleared.

If a jumper tab is installed in the energize position, that alarm relay will be in the energized mode. The ener­gized mode will energize or activate the alarm relay when there is no alarm condition and de-energize or de-acti­vate the alarm relay when there is an alarm condition. The de-energized mode (jumper removed) will energize or
activate the alarm relay during an alarm condition and de-energize or de-activate the alarm relay when there is
no alarm condition.

If a jumper tab is installed in the ascending position, that alarm relay will be in the ascending mode. The
ascending mode will cause an alarm to fire when the gas concentration detected is greater than or equal to the
alarm set point. The descending mode (jumper removed) will cause an alarm to fire when the gas concentration
detected is lesser than or equal to the alarm set point. Except in special applications, combustible gas monitor­ing will require alarms to fire in

“ASCENDING”

gas conditions.

Any unused jumper tabs should be stored on the connector board on the terminal strip labeled “Unused
Jumpers” (see figure 3).

f) If applicable, set the RS-485 ID number via the two rotary dip switches located on the preamp board (see figure

5). There are 256 different ID numbers available which are based on the hexidecimal numbering system. If RS­485 communications are used, each sensor must have its own unique ID number. Use a jewelers screwdriver to
set the rotary dip switches according to the hexidecimal table listed below. If RS-485 communications are not

used, leave the dip switches in the default position which is zero/zero (0)-(0).

g) Replace the plug-in control circuit and replace the junction box cover.

Figure #5

Figure #4

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.11

3.5.6 Remote Mounting Applications

Hexidecimal Table

ID# SW1 SW2

none 00

101
202
303
404
505
606
707
808

909
10 0A
11 0B
12 0C
13 0D
14 0E
15 0F
16 10
17 11
18 12
19 13
20 14
21 15
22 16
23 17
24 18
25 19
26 1A
27 1B
28 1C
29 1D
30 1E
31 1F
32 20
33 21
34 22
35 23
36 24
37 25
38 26
39 27
40 28
41 29
42 2A

ID#

SW1 SW2

43 2B
44 2C
45 2D
46 2E
47 2F
48 30
49 31
50 32
51 33
52 34
53 35
54 36
55 37
56 38
57 39
58 3A
59 3B
60 3C
61 3D
62 3E
63 3F
64 40
65 41
66 42
67 43
68 44
69 45
70 46
71 47
72 48
73 49
74 4A
75 4B
76 4C
77 4D
78 4E
79 4F
80 50
81 51
82 52
83 53
84 54
85 55

ID#

SW1 SW2

86 56
87 57
88 58
89 59
90 5A
91 5B
92 5C
93 5D
94 5E
95 5F
96 60
97 61
98 62

99 63
100 64
101 65
102 66
103 67
104 68
105 69
106 6A
107 6B
108 6C
109 6D
110 6E
111 6F
112 70
113 71
114 72
115 73
116 74
117 75
118 76
119 77
120 78
121 79
122 7A
123 7B
124 7C
125 7D
126 7E
127 7F
128 80

ID#

SW1 SW2

129 81
130 82
131 83
132 84
133 85
134 86
135 87
136 88
137 89
138 8A
139 8B
140 8C
141 8D
142 8E
143 8F
144 90
145 91
146 92
147 93
148 94
149 95
150 96
151 97
152 98
153 99
154 9A
155 9B
156 9C
157 9D
158 9E
159 9F
160 A0
161 A1
162 A2
163 A3
164 A4
165 A5
166 A6
167 A7
168 A8
169 A9
170 AA
171 AB

ID#

SW1 SW2

172 AC
173 AD
174 AE
175 AF
176 B0
177 B1
178 B2
179 B3
180 B4
181 B5
182 B6
183 B7
184 B8
185 B9
186 BA
187 BB
188 BC
189 BD
190 BE
191 BF
192 C0
193 C1
194 C2
195 C3
196 C4
197 C5
198 C6
199 C7
200 C8
201 C9
202 CA
203 CB
204 CC
205 CD
206 CE
207 CF
208 D0
209 D1
210 D2
211 D3
212 D4
213 D5
214 D6

ID#

SW1 SW2

215 D7
216 D8
217 D9
218 DA
219 DB
220 DC
221 DD
222 DE
223 EF
224 E0
225 E1
226 E2
227 E3
228 E4
229 E5
230 E6
231 E7
232 E8
233 E9
234 EA
235 EB
236 EC
237 ED
238 EE
239 FF
240 F0
241 F1
242 F2
243 F3
244 F4
245 F5
246 F6
247 F7
248 F8
249 F9
250 FA
251 FB
252 FC
253 FD
254 FE
255 FF

Some sensor mounting applications require that the gas sensor head be remotely mounted away from the sensor
transmitter. This is usually true in instances where the gas sensor head must be mounted in a location that is diffi­cult to access. Such a location creates problems for maintenance and calibration activities. Detcon provides the IR­622 sensor in a remote-mount configuration in which the sensor (Model IR-622-RS) and the transmitter (Model IR­622-RT) are provided in their own condulet housing and are interfaced together with a six conductor cable.
Shielded cable is required and must be installed in its own (unshared) conduit (use Alpha Wire Company #6342
cable). A maximum of 100 feet of separation is allowed. Reference figure 5A for wiring diagram.

3.6 START UP

Upon completion of all mechanical mounting and termination of all field wiring, apply system power and observe
the following normal conditions:

a) IR-622 “Fault” LED is off.
b) A reading of 0% LEL should be indicated upon conclusion of a 12 second “warming up” cycle.

NOTE:

od will begin again once power has been restored.

Material Requirements

* Detcon PN 3270 MicroSafe™ Programming Magnet
* Digital volt/ohm meter.

All alarms will be disabled for 1 minute after power up. In the event of power failure, the alarm disable peri-

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.12

Magnetic Programming Tool

1234

RED

BRN

WHT

BLK

Remote Transmitter

IR-622-RT

Remote Sensor

IR-622-RS

WHT

BLK

YEL

BLU

RED

BRN

56

YEL

BLU

Figure #5A

3.6.2 Programming Magnet Operating Instructions

Operator interface to MicroSafe™ gas detection products is via magnetic switches located behind the transmitter
face plate. DO NOT remove the glass lens cover to calibrate or change programming parameters. Two switches
labeled “PGM 1” and “PGM 2” allow for complete calibration and alarm level programming without removing the
enclosure cover, thereby eliminating the need for area de-classification or the use of hot permits.

A magnetic programming tool (see figure 6) is used to operate the switches. Switch action is defined as momentary
contact, 3 second hold, and 30 second hold. In momentary contact use, the programming magnet is waved over a
switch location. In 3 second hold, the programming magnet is held in place over a switch location for 3 or more
seconds. In 30 second hold, the programming magnet is held in place over a switch location for 30 or more sec­onds. Three and thirty second hold is used to enter or exit calibration and program menus while momentary con­tact is used to make adjustments. The location of “PGM 1” and “PGM 2” are shown in figure 7.

NOTE: If, after entering the calibration or program menus, there is no interaction with the menu items for more
than 30 seconds, the sensor will return to its normal operating condition.

3.6.3 Initial Operational Tests

After a warm up period has been allowed for, the sensor should be checked to verify sensitivity to combustible

Figure #6

hydrocarbon gas.

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.13

detcon inc.

P

rogram Switch #2

FLT

ALM

1

CAL

M

icroSafe™ LEL Gas Sensor

HOUS TON , TEX AS

PGM 2

P

GM 1

ALM

2

MODEL IR-622

CONTRAST

Alarm & Cal LEDs

Program Switch #1

Menu Driven Display

Plug-in Microprocessor Control Circuit

Display Contrast Adjust

Figure #7

NOTE: If the sensor has been configured for calibration with a gas other than methane you will need to use
that gas. See section 3.7 for further information on calibration gas.

Material Requirements

* Detcon PN 6132 Threaded Calibration Adapter
* Span Gas 50% LEL methane in air at a controlled flow rate between 200 ml/min.

a) Attach the calibration adapter to the threaded sensor housing. Apply a the test gas at a controlled f low rate of

200 ml/m. Observe that the LCD display increases to a level of 20% or higher.

b) Remove the test gas and observe that the LCD display decreases to “0 % LEL”

.

c) If alarms are activated during the test, and have been programmed for latching operation, reset them according to

the instructions in section 3.9.2.

Initial operational tests are complete. Detcon combustible gas sensors are pre-calibrated prior to shipment and will,
in most cases, not require significant adjustment on start up. However, it is recommended that a complete calibra­tion test and adjustment be performed within 24 hours of installation. Refer to calibration instructions in later text.

3.7 CALIBRATION

Material Requirements

* Detcon PN 3270 MicroSafe™ Programming Magnet
* Detcon PN 6132 Threaded Calibration Adapter
* Span Gas containing the applicable calibration gas in air. Span gas concentration is recommended at 50% of

range (which is the factory default) at a controlled f low rate of 200 ml/min. Other concentrations can be used
as long as they fall within 10% to 90% of range. See section 3.7.2 for details.

3.7.1 Calibration Procedure - Zero

NOTE: Before performing a zero calibration, be sure there is no background target gas present.

a) Enter the calibration menu by holding the programming magnet stationary over “PGM 1” (see figure 7) for 3 sec-

onds until the display reads “1-ZERO 2-SPAN”, then withdraw the magnet. Note that the “CAL” LED is on.

b) Next, enter the zero menu by holding the magnet stationary over “PGM 1” for 3 seconds until the display

reads: “ZERO 0%”, then withdraw the magnet. The sensor has now entered the auto zero mode. When it is
complete the display will read “ZERO COMPLETE” for 5 seconds and then return to the normal operations
menu, “0 % LEL”.

NOTE 1: If the circuitry is unable to adjust the zero to the proper setting the sensor will enter a calibration
fault mode which will cause the display to alternate between the sensor’s current status reading and the calibra­tion fault screen which appears as: “CAL FAULT” (see section 3.7.3).

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.14

NOTE 2: When a “cal fault” occurs, the sensor microprocessor retains its previous calibration references.
Zero calibration is complete.

3.7.2 Calibration Procedure - Span

CAUTION:

Verification of the correct calibration gas level setting and calibration span gas concentration is

required before “span” calibration. These two numbers must be equal.

Calibration consists of entering the calibration function and following the menu-displayed instructions. The display
will ask for the application of span gas in a specific concentration. This concentration is equal to the calibration gas
level setting. The factory default setting for span gas concentration is 50% LEL. In this instance, a span gas contain­ing a concentration equal to 50% LEL is required. If a span gas containing 50% LEL is not available, other concen­trations may be used as long as they fall within 10% to 90% of range. However, any alternate span gas concentra­tion value must be programmed via the calibration gas level menu before proceeding with span calibration. Follow
the instructions below for span calibration.
a) Verify the current calibration gas level setting as indicated by the programming status menu. To do this, follow

the instructions in section 3.8 and make note of the setting found in listing number 14. The item appears as

“CalLevel @ xx%”.

b) If the calibration gas level setting is equal to your calibration span gas concentration, proceed to item “f”. If

not, adjust the calibration gas level setting so that it is equal to your calibration span gas concentration, as
instructed in items “c” through “e”.

c) Enter the programming menu by holding the programming magnet stationary over “PGM 2” for 30 seconds

until the display reads “VIEW PROG STATUS”, then withdraw the magnet. At this point you can scroll
through the programming menu by momentarily waving the programming magnet over “PGM 1” or “PGM 2”.
The menu options are: View Program Status, Set Alarm 1 Level, Set Alarm 2 Level, Set Gas Factor, Set Cal
Factor, and Set Cal Level.

d) From the programming menu scroll to the calibration level listing. The menu item appears as: “SET CAL

LEVEL”. Enter the menu by holding the programming magnet stationary over “PGM 1” for 3 seconds until
the display reads “CalLevel @ ##%”, then withdraw the magnet. Use the programming magnet to make an
adjustment to “PGM 1” to increase or “PGM 2” to decrease the display reading until the reading is equal to the
desired calibration span gas concentration. Exit to the programming menu by holding the programming magnet
over “PGM1” for 3 seconds.

e) Exit back to normal operation by holding the programming magnet over “PGM 2” for 3 seconds, or automati-

cally return to normal operation in 30 seconds.

f) From the calibration menu “1-ZERO 2-SPAN” (section 3.7.1-a) proceed into the span adjust function by

holding the programming magnet stationary over “PGM 2” for 3 seconds until the display reads “APPLY
xx% LEL” then withdraw the programming magnet. The x’s here indication the gas concentration requested.

g) Apply the calibration gas at a flow rate of between 200 milliliters per minute. As the sensor signal changes, the

display will change to “SPAN XX%”. The “XX” part of the reading indicates the actual gas reading which will
increase until the sensor stabilizes. When the sensor signal is stable it will auto span to the request concentra­tion and the display will change to “SPAN COMPLETE” for two seconds and then “REMOVE GAS”.
Remove the gas. When the signal level has fallen below 10% of full scale, the display will return to the normal
operation menu, “0 % LEL”.

NOTE 1: If the circuitry is unable to adjust the span to the proper setting the sensor will enter into the calibra­tion fault mode which will cause the display to alternate between the sensor’s current status reading and the cal­ibration fault screen which appears as: “CAL FAULT” (see section 3.7.3).

NOTE 2: If, after entering the span function, more than one minute elapses before calibration gas is applied,
the sensor will enter the calibration fault mode which will cause the display to alternate between the sensor’s
current status reading and the calibration fault screen which appears as: “CAL FAULT” (see section 3.7.3).

Span calibration is complete.

3.7.3

Additional Notes

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.15

1. Upon entering the calibration menu, the 4-20 mA signal drops to 2 mA and is held at this level until you
return to normal operation.

2. If during calibration the sensor circuitry is unable to attain the proper adjustment for zero or span, the sensor will
enter into the calibration fault mode which will activate fault alarm functions (see section 3.10) and cause the dis­play to alternate between the sensor’s current status reading and the calibration fault screen which appears as:
“CAL FAULT”. If this occurs you may attempt to recalibrate by entering the calibration menu as described in
section 3.8.1-a. If the sensor fails again, defer to technical trouble shooting.

3.7.4 Calibration Frequency

In most applications, quarterly zero calibration and annual span calibration intervals will assure reliable detection.
However, industrial environments differ. Upon initial installation and commissioning, close frequency tests should
be performed monthly. Test results should be recorded and reviewed to determine a suitable calibration interval.

3.8 STATUS OF PROGRAMMING, ALARMS, CALIBRATION LEVEL, RS-485 ID, TEMPERATURE, AND SENSOR LIFE

The programming menu has a programming status listing that allows the operator to view the gas, range, and soft­ware version number of the program, as well as the current alarm settings, calibration gas level setting, RS-485 ID
number, sensor temperature, and estimated remaining sensor life. The programming menu also allows the calibra­tion gas level setting (see section 3.72), and alarm levels (see section 3.9).

The following procedure is used to view the programming status of the sensor:

a) First, enter the programming menu by holding the programming magnet stationary over “PGM 2” for 30 sec-

onds until the display reads “VIEW PROG STATUS”, then withdraw the magnet. At this point you can
scroll through the programming menu by momentarily waving the programming magnet over “PGM 1” or
“PGM 2”. The menu options are: View Program Status, Set Alarm 1 Level, Set Alarm 2 Level, and Set Cal
Level.

b) Next, scroll to the “VIEW PROG STATUS” listing and then hold the programming magnet over “PGM 1”

for 3 seconds. The menu will then automatically scroll, at five second intervals, through the following informa­tion before returning back to the “VIEW PROG STATUS” listing.

The gas type, range of detection and software version number. The menu item appears as:

1 ­2 - The alarm set point level of alarm 1. The menu item appears as: “ALM1 SET @ 20%”
3 - The alarm firing direction of alarm 1. The menu item appears as: “ALM1 ASCENDING”
4 - The alarm relay latch mode of alarm 1. The menu item appears as: “ALM1 NONLATCHING”
5 - The alarm relay energize state of alarm 1. The menu item appears as: “ALM1 DE-ENERGIZED”
6 - The alarm set point level of alarm 2. The menu item appears as: “ALM2 SET @ 60%”
7 - The alarm firing direction of alarm 2. The menu item appears as: “ALM2 ASCENDING”
8 - The alarm relay latch mode of alarm 2. The menu item appears as: “ALM2 LATCHING”
9 - The alarm relay energize state of alarm 2. The menu item appears as: “ALM2 DE-ENERGIZED”
10 - The alarm relay latch mode of the fault alarm. The menu item appears as: “FLT NONLATCHING”
11 - The alarm relay energize state of the fault alarm. The menu item appears as: “FLT ENERGIZED”
12 - The calibration gas level setting. The menu item appears as: “CalLevel @ xx%”
13 - Identification of the RS-485 ID number setting. The menu item appears as: “485 ID SET @ 1”
14 - Sensor temperature in °C appears as: “TEMPERATURE xx °C”
15 - The estimated remaining sensor life. The menu item appears as: “OPTICS AT 100%”

c) Exit back to normal operations by holding the programming magnet over “PGM 2” for 3 seconds, or automati-

cally return to normal operation in 30 seconds.

“LEL 0-100 V6.0”

3.9 PROGRAMMING ALARMS

3.9.1 Alarm Levels

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.16

Both alarm 1 and alarm 2 levels are factory set prior to shipment. Alarm 1 is set at 20%; alarm 2 at 60%. Both
alarms can be set in 1% increments from 10 to 90%. The following procedure is used to change alarm set points:

a) First, enter the programming menu by holding the programming magnet stationary over “PGM 2” for 30 sec-

onds until the display reads “VIEW PROG STATUS”, then withdraw the magnet. At this point you can
scroll through the programming menu by momentarily waving the programming magnet over “PGM 1” or
“PGM 2”. The menu options are: View Program Status, Set Alarm 1 Level, Set Alarm 2 Level, and Set Cal
Level.

b) ALARM 1 LEVEL

“SET ALARM 1 LEVEL”. Enter the menu by holding the programming magnet stationary over “PGM 1”
for 3 seconds until the display reads “SET ALM1 @ 20%”, then withdraw the magnet. Use the programming
magnet to make an adjustment to “PGM 1” to increase or “PGM 2” to decrease the display reading until the
reading is equal to the desired alarm set point. Exit to the programming menu by holding the programming
magnet over “PGM1” for 3 seconds, or automatically return to the programming menu in 30 seconds.

c) ALARM 2 LEVEL

“SET ALARM 2 LEVEL”. Enter the menu by holding the programming magnet stationary over “PGM 1”
for 3 seconds until the display reads “SET ALM2 @ 60%”, then withdraw the magnet. Use the programming
magnet to make an adjustment to “PGM 1” to increase or “PGM 2” to decrease the display reading until the
reading is equal to the desired alarm set point. Exit to the programming menu by holding the programming
magnet over “PGM1” for 3 seconds, or automatically return to the programming menu in 30 seconds.

d) Exit back to normal operations by holding the programming magnet over “PGM 2” for 3 seconds, or automati-

cally return to normal operation in 30 seconds.

3.9.2 Alarm Reset

An alarm condition will cause the applicable alarm to activate its corresponding relay and LED. If alarm 1, alarm 2,
or fault alarms have been programmed for latching relays, an alarm reset function must be activated to reset the
alarms after an alarm condition has cleared. To reset the alarms, simply wave the programming magnet over either
“PGM 1” or “PGM 2”, momentarily, while in normal operations mode and note that the corresponding alarm
LED(s) turn off.

From the programming menu scroll to the alarm 1 level listing. The menu item appears as:

From the programming menu scroll to the alarm 2 level listing. The menu item appears as:

3.9.3 Other Alarm Functions

Alarms are factory programmed to be non-latching, de-energized; and to fire under ascending gas conditions. The
fault alarm relay is programmed as normally energized which is useful for detecting a 24VDC power source failure.
All alarm functions are programmable via jumper tabs. Changing alarm functions requires the sensor housing to be
opened, thus declassification of the area is required. See section 3.5.5-e for details.

3.10 PROGRAM FEATURES

Model IR-622 MicroSafe™ Sensors incorporate a comprehensive program to accommodate easy operator interface
and fail-safe operation. Program features are detailed in this section. Each sensor is factory tested, programmed, and
calibrated prior to shipment.

Over Range

When the sensor detects gas greater than 100% LEL, it will cause the display to flash “100 % LEL” on and off.

Optics Life

The Optics Life feature is a reference based on the signal output from the optical sensor. When an optical sensor
life of 25% or less remains, the optical sensor should be replaced within a reasonable maintenance schedule.

Calibration Fault

If during calibration the sensor circuitry is unable to attain the proper adjustment for zero or span, the sensor will
enter into the calibration fault mode and cause the display to alternate between the sensor’s current status reading and

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.17

the calibration fault screen which appears as: “CAL FAULT.2”.

The following conditions will cause a calibration fault:
1 - Zero calibration cannot converge.
2 - Auto span cannot converge (too noisy or too unstable).
3 - Span gas is not applied before 1 minute elapses.

Fail-Safe/Fault Supervision

Model IR-622 MicroSafe™ sensors are programmed for fail-safe operation. All of the fault conditions listed below
will activate the fault relay, illuminate the fault LED, cause the mA output to drop to zero (0) mA, and cause the
display to read its corresponding fault condition.

Memory Error

If the processor can’t save values to memory, the display will indicate: “MEMORY ERROR”.

Zero Fault

If the sensor should drift below –10%, the display will indicate: “ZERO FAULT”.

Lamp Fault

If the lamp signal is lost, the display will indicate: “LAMP FAULT.2”.

Reference Peak High Fault

If the reference peak signal is too high (>3600), the display will indicate: “SIGNAL FAULT.31”.

Active Peak High Fault

If the active peak signal is too high (>3600), the display will indicate: “SIGNAL FAULT.32”.

Reference Peak Low Fault

If the reference peak signal is too low (<500), the display will indicate: “SIGNAL FAULT.41”.

Active Peak Low Fault

If the active peak signal is too low (<500), the display will indicate: “SIGNAL FAULT.42”.

Reference Peak to Peak Low Fault

If the reference peak to peak signal is too low (<200), the display will indicate: “SIGNAL FAULT.51”.

Active Peak to Peak Low Fault

If the active peak to peak signal is too low (<200), the display will indicate: “SIGNAL FAULT.52”.

3.11 RS-485 PROTOCOL

Detcon MicroSafe™ sensors feature Modbus™ compatible communications protocol and are addressable via rotary
dip switches for multi-point communications. Other protocols are available. Contact the Detcon factory for specific
protocol requirements. Communication is two wire, half duplex 485, 9600 baud, 8 data bits, 1 stop bit, no parity,
with the sensor set up as a slave device. A master controller up to 4000 feet away can theoretically poll up to 256
different sensors. This number may not be realistic in harsh environments where noise and/or wiring conditions
would make it impractical to place so many devices on the same pair of wires. If a multi-point system is being uti­lized, each sensor should be set for a different address. Typical address settings are: 01, 02, 03, 04, 05, 06, 07, 08, 09,
0A, 0B, 0C, 0D, 0E, 0F, 10, 11, etc.

In most instances, RS-485 ID numbers are factory set or set during installation before commissioning. If required,
the RS-485 ID number can be set via rotary dip switches located on the preamp circuit board. However, any change
to the RS-485 ID number would require the sensor housing to be opened, thus declassification of the area would
be required. See section 3.5.4-f for details on changing the RS-485 ID number.

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.18

The following section explains the details of the Modbus™ protocol that the IR-622 MicroSafe™ sensor supports.

Code 03 - Read Holding Registers, is the only code supported by the transmitter. Each transmitter contains 6 hold­ing registers which reflect its current status.

Register #

High Byte Low Byte

40000 Gas type Sensor Life

Gas type is one of the following:
01=CO, 02=H2S, 03=SO2, 04=H2, 05=HCN, 06=CL2, 07=NO2, 08=NO, 09=HCL, 10=NH3, 11=LEL, 12=O2

Sensor life is an estimated remaining use of the sensor head, between 0% and 100%
Example: 85=85% sensor life

Register # High Byte Low Byte
40001 Detectable Range

i.e. 100 for 0-100 ppm, 50 for 0-50% LEL, etc.

Register #

High Byte Low Byte

40002 Current Gas Reading

The current gas reading as a whole number. If the reading is displayed as 23.5 on the display, this register would
contain the number 235.

Register #

High Byte Low Byte
40003 Alarm 1 Setpoint
This is the trip point for the first alarm.

Register # High Byte Low Byte
40004 Alarm 2 Setpoint

This is the trip point for the second alarm.

Register #

High Byte Low Byte
40005 Status Bits Status Bits

High Byte
Bit 7 Not used, always 0
Bit 6 Not used, always 0
Bit 5 Not used, always 0
Bit 4 Not used, always 0
Bit 3 1-Unit is in calibration 0-Normal operation
Bit 2 1-Alarm 2 is ascending 0-Alarm 2 is descending
Bit 1 1-Alarm 2 is normally energized 0-Alarm 2 is normally de-energized
Bit 0 1-Alarm 2 is latching 0-Alarm 2 is non-latching

Low Byte
Bit 7 1-Alarm 2 Relay is energized 0-Alarm 2 Relay is not energized
Bit 6 1-Alarm 1 is ascending 0-Alarm 1 is descending
Bit 5 1-Alarm 1 is normally energized 0-Alarm 1 is normally de-energized

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.19

Bit 4 1-Alarm 1 is latching 0-Alarm 1 is non-latching
Bit 3 1-Alarm 1 Relay is energized 0-Alarm 1 Relay is not energized
Bit 2 1-Fault is normally energized 0-Fault is normally de-energized
Bit 1 1-Fault is latching 0-Fault is non-latching
Bit 0 1-Fault Relay is energized 0-Fault Relay is not energized

The following is a typical Master Query for device # 8:

Field

Name HEX DEC RTU
Slave Address 08 8 0000 1000
Function 03 3 0000 0011
Start Address Hi 00 0 0000 0000
Start Address Lo 00 0 0000 0000
No. of Registers Hi 00 0 0000 0000
No. of Registers Lo 06 6 0000 0110
CRC ## #### ####
CRC ## #### ####

The following is a typical Slave Response from device # 8:

Field

Name HEX DEC RTU
Slave Address 08 8 0000 1000
Function 03 3 0000 0011
Byte Count 0C 12 0000 1100
Reg40000 Data Hi 02 2 0000 0010
Reg40000 Data Lo 64 100 0110 0100
Reg40001 Data Hi 00 0 0000 0000
Reg40001 Data Lo 64 100 0110 0100
Reg40002 Data Hi 00 0 0000 0000
Reg40002 Data Lo 07 7 0000 0111
Reg40003 Data Hi 00 0 0000 0000
Reg40003 Data Lo 0A 10 0000 1010
Reg40004 Data Hi 00 0 0000 0000
Reg40004 Data Lo 14 20 0001 0100
Reg40005 Data Hi 05 5 0000 0101
Reg40005 Data Lo 50 80 0101 0000
CRC ## #### ####
CRC ## #### ####

Additional Notes:
The calibration LED will light when the transmitter is sending a response to a Master Query.
Communications are 9600 baud, 8 data bits, 1 stop bit, No parity, half duplex 485.

3.12 DISPLAY CONTRAST ADJUST

Model IR-622 MicroSafe™ sensors feature a 16 character backlit liquid crystal display. Like most LCDs, character
contrast can be affected by viewing angle and temperature. Temperature compensation circuitry included in the
MicroSafe™ design will compensate for this characteristic, however temperature extremes may still cause a shift in
the contrast. Display contrast can be adjusted by the user if necessary. However, changing the contrast requires that
the sensor housing be opened, thus declassification of the area is required.

To adjust the display contrast, remove the enclosure cover and use a jewelers screwdriver to turn the contrast
adjust screw located beneath the metallic face plate. The adjustment location is marked “CONTRAST”. See figure 7
for location.

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.20

3.13 OPTICAL SENSOR REPLACEMENT PROCEDURE

Should the optical gas sensor element (part number 370-365871-212) require replacement, use the following proce­dure:
1 - (A) If the sensor is mounted in a classified area, system power to the transmitter must first be removed before

proceeding further.

(B) If in an unclassified area, remove front enclosure cover and unplug transmitter module.
2 - Remove lower half of sensor housing using an alan wrench (3 screws).
3 - Remove existing optical sensor and replace with new optical sensor (part number 370-365871-212).
4 - Re-install lower half of sensor housing.
5 - Restore system power (if classified) or plug in transmitter module and replace enclosure cover (if unclassified).
6 - As the unit reports “WARMING UP” message, use the magnetic programming tool and swipe across PGM1 or

PGM2. This will take the unit into a one-time gain setting mode which takes 1 minute to complete.
7 - Perform a new zero calibration followed by a new span calibration (see section 3.7).

3.14 TROUBLE SHOOTING GUIDE

Calibration Faults (CalFault.2)
Calibration Faults (Zero or Span) can be cleared by successfully repeating the calibration attempt. Refer to the appropriate sec­tion in the Operator Manual and follow procedure.

Clearing Faults (Memory Error, LampFault.2, and Signal Faults.XX)
If a Fault Diagnostic occurs (Memory Error, Lamp Fault, or Signal Fault.XX) it may be a permanent problem or temporary. If
it is a temporary fault, it may be cleared using the following 1) and 2) actions. If it can not be cleared then it is a permanent
problem and advanced troubleshooting may be necessary.

1) Unplug and replug transmitters to cycle power. Determine if fault has cleared.

2) Re-initialize unit by unplugging and re-plugging transmitter and then immediately swiping your magnet over PGM1. The
unit will go into an initializing mode and reset the optical gain settings. Observe unit as the gain setting (GN) is counted down
and Ia or Ir is counted up to 2700. Record the gain set value last reported as Ia or Ir reaches 2700. Next record the final Ia and
Ir values which are displayed next. Finally record the temperature which is displayed last. Determine if fault has cleared.

Normal Readings are defined below and should be recorded to discuss with Detcon Technical Service Staff:

Gain Set:55-130
Ir: 2000-2700
Ia: 1800-2700
Temp: 32C 40C (approximately 10C higher than ambient temperature)

3) Contact Detcon for service and repair if above mentioned troubleshooting actions have not solved problem.

Zero Fault
Zero Fault is an indication that the zero level has drifted below –10% of range.
Zero Fault can be cleared by re-calibrating zero in target gas “free” air.

Non-readable display

1. If display has blue background when hot, install sunshade to reduce temperature.

2. If poor contrast, adjust contrast pot accordingly.

Nothing Displayed – Transmitter not responding

1. Verify condulet has no accumulated water or abnormal corrosion.

2. Verify required DC power is applied to correct terminals.

3. Swap with a known-good transmitter to determine if transmitter is faulty.

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.21

Bad 4-20 mA output or RS485 Output

1. Check that wiring is connected to correct terminal outputs.

2. Swap with a known-good transmitter to determine if transmitter is faulty

Unstable output/Sudden Spiking/Nuisance Alarms

. Check condulet for accumulated water.

1

2. Check transmitter and Terminal PCB for abnormal corrosion.

3. Determine if problem correlates with condensation cycles.

4. Add/change Detcon condensation prevention packet.

5. Check for unstable power supply.

6. Check for inadequate grounding.

7. If correlates with radio communications then use Detcon RFI filter accessory.

8. Contact Detcon for assistance in optimizing shielding, grounding, and RFI protection.

Excessive Span Drift or Slow Response

1. Verify correct cal gas flow rate and proper use of the cal gas adapter.

2. Check validity of cal gas via the expiration date and use pull tube if necessary.

3. Check for obstructions through s/s sinter element (including being wet).

4. Replace plug-in sensor if Optics Life is <25%.

Drifting Zero
It may be the correct reading if there are real gas leaks or the sensor was zero calibrated when actual gas was present and subse­quently cleared.

1. Recalibrate zero using target gas “free” sample.

2. Replace plug-in sensor if Optics Life is <25%.

3.15 SPARE PARTS LIST

613-010000-000 Sensor rain shield
613-120000-000 Sensor splash guard
943-000006-132 Threaded Calibration Adapter
390-000087-000 IR sensor housing assembly (plug-in detector PN 370-365871-212, not included)
370-365871-212 Field replaceable NDIR optical plug in sensor
926-225500-100 IR-622 Plug-in control circuit
500-002042-000 IR Connector board
327-000000-000 Programming Magnet
897-850800-000 3 port enclosure less cover
897-850700-000 Enclosure glass lens cover
960-202200-000 Condensation prevention packet (replace annually).

3.16 WARRANTY

Detcon, Inc., as manufacturer, warrants each NDIR optical plug in sensor (part no. 370-365871-212), for a pro-rated
five year period under the conditions described as follows: The warranty period begins on the date of shipment to

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.22

Spash Guard

Rain Shield

Enclosure less cover

IR Connector Board

Cal ib ra tio n A da pte r

Enclosure glass lens cover

P

lug-in control circuit

Field replaceable plug-in optical sensor

I

R Sensor Housing Assembly

P

rogramming Magnet

Condensation
P

revention Packet

(

replace annually)

Figure #8

the original purchaser and ends f ive years thereafter. The sensor element is warranted to be free from defects in
material and workmanship. Should any sensor fail to perform in accordance with published specif ications within
the warranty period, return the defective part to Detcon, Inc., 3200 A-1 Research Forest Dr., The Woodlands, Texas
77381, for necessary repairs or replacement.

3.17 SERVICE POLICY

Detcon, Inc., as manufacturer, warrants under intended normal use each new MicroSafe™ plug-in control circuit to
be free from defects in material and workmanship for a period of two years from the date of shipment to the origi­nal purchaser. Detcon, Inc., further provides for a five year fixed fee service policy wherein any failed transmitter
shall be repaired or replaced as is deemed necessary by Detcon, Inc., for a fixed fee of $65.00. The fixed fee service
policy shall affect any factory repair for the period following the two year warranty and shall end f ive years after
expiration of the warranty. All warranties and service policies are FOB the Detcon facility located in The
Woodlands, Texas.

3.18 SOFTWARE FLOW CHART

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.23

NORMAL

OPERATION

CALIBRATION

PGM1 (3) PGM2 (3)

PGM1 (M) PGM2 (M)

PGM1 (3)

SET ALM1 @ ##%

INC

DEC

P

GM1 (3)PGM2 (M)

1-ZERO 2-SPAN

LEGEND

PGM1 - program switch location #1

PGM2 - program switch location #2

(M) - momentary pass of magnet

(3) - 3 second hold of magnet

(30) - 30 second hold of magnet

INC - increase

DEC - decrease

# - numeric value

AUTO ZERO

AUTO SPAN

SET ALARM 1 LEVEL

LEL 0-100 V#.#

P

GM1 (3)PGM2 (M)

VIEW PROG STATUS

ALM1 SET @ ##%

ALM2 SET @ ##%

PGM1 (M) PGM2 (M)

PGM1 (3)

SET ALM2 @ ##%

INC

DEC

P

GM1 (3)PGM2 (M)

SET ALARM 2 LEVEL

P

GM2 (3)

P

GM2 (3)

P

GM2 (3)

CAL LEVEL @ ##%

ALM1 (Firing Direction)

ALM1 (Latch State)

ALM1 (Energize State)

ALM2 (Firing Direction)

ALM2 (Latch State)

ALM2 (Energize State)

FLT (Latch State)

FLT (Energize State)

PGM1 (3) PGM1 (M)

P

GM2 (30) PGM2 (M)

ALARM RESET

A

LARM RESET

485 ID SET @ #

OPT IC S AT # #%

TEMPERATURE ##∞C

PGM1 (M) PGM2 (M)

PGM1 (3)

CAL LEVEL @ ##%

INC

DEC

P

GM1 (3)PGM2 (M)

SET CAL LEVEL

P

GM2 (3)

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

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

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

Detcon Model IR-622 Combustible Hydrocarbon Sensor PG.24