™
detcon inc.
Detcon MicroSafe
IR-640 Carbon Dioxide Sensor (0-5%CO2)
IR642 Carbon Dioxide Sensor (10%-100%)
Operator’s Installation & Instruction Manual
November 26, 2007 • Document #2196 • Version 6.4
CAUTION:
Before operating the Model IR-640/IR-642 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 Trouble Shooting Guide
3.15 Spare Parts List
3.16 Warranty
3.17 Service Policy
3.18 Software Flow Chart
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.2
3.0 DESCRIPTION
Detcon MicroSafe™ Model IR-640, carbon dioxide gas sensors are non-intrusive “Smart” sensors designed to detect
and monitor CO2gas in air over the 0-5% range. The Detcon MicroSafe™ Model IR-642 CO2 gas sensor measures
in the 10-100% Range. 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 f lexibility 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 CO2. 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.
Typical ranges of detection are 0-0.30%, 0-0.50%, 0-1.00%, 0-2.00%, 0-3.00% and 0-5% with the IR640. Typical
Ranges with the IR642 are 0-10%, 0-25%, 0-50%, 0-100%. Other ranges may be accommodated and all ranges are
covered by this manual. To determine the range of detection, refer to the instructions found in section 3.8.
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 CO2as 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
CO2absorbs light. The “reference” pyroelectric detector is covered by a filter specific to the non-absorbing part of the
IR spectrum. When CO2is 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 CO2concentration.
Detcon Model IR-640/IR-642 Carbon Dioxide 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
F
LT
A
LM
1
C
AL
MicroSafe™ CO2 Gas Sensor
HOUS TON, TEX AS
PGM 2
PGM 1
A
LM
2
M
ODEL
I
R-640
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
Optical Filter
CO
2
CO
2
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-640/IR-642 Carbon Dioxide 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
CO2 Not Present
CO2 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 CO2diffuses through a sintered stainless steel f lame 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 CO2absorbs light. The “reference” pyroelectric
detector is covered by a filter specific to the non-absorbing part of the IR spectrum. When present, CO2absorbs 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 CO2. The ratio of the “active” and
“reference” detector signal outputs is then used to compute CO2concentration. 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 CO2, as shown in the illustration below. Typical zero calibration intervals would be 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.
The MicroSafe™ IR-640/IR-642 is factory calibrated for a specific CO2 range (see section 3.8 to determine range). The detector will be factory calibrated for the range specified at time of order. If a CO2range other than that specified at time of order
is desired, 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 corrosion. These deposits may reduce the optical reflectivity inside the sensor, and although accurate readings are continually maintained, excessive loss in useable signal eventually gives way to noise and unstable readings. The optical sensor may, over long
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-640/IR-642 has an extensive list of Fault Diagnostics to alert and pin-point operational problems. See section
3.10
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.5
3.2 APPLICATION
Functional
Block
Diagram
Functional
Block
Diagram
Analog 4-20 mA Out
Power In
Relays Out
Pre-Amp Display
Tem per atu re
Compensation
Alarm & Fault
Relays
RS-485 & 4-20mA
Micro-
processor
Tran smit ter
Power Supply
Optical
Sensor
I/O Circuit
Protection
Serial RS-485 Out
0
4
8
12
16
20
2
0406080100
% of Range of Detection
mA DC Signal Output
Output Response Curve
Model IR-640/IR-642 MicroSafe™ sensors are designed to detect and monitor CO2gas in ambient air. Minimum sensitivity and scale resolution is 0.01%. 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.
3.3 SPECIFICATIONS
Method of Detection
NDIR Optical
Electrical Classification
Class I; Groups B, C, D; Div. 1.
Response Time
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.6
T50 < 15 seconds; T90 < 35 seconds
Clearing Time
0% < 35 seconds
9
Repeatability
± 3% FS
Range
0 - 0.3/0.5/1/2/3/5% withthe IR-640
0-10/0-25/0-50/0-100% with the IR-642
Operating Temperature
-40° to +175° F
Accuracy
± 5% FS
Sensor Warranty
5 year pro-rated
Power Consumption
Normal operation = 95 mA (2.3 watts); Full alarm = 123 mA (<3 watts)
Zero Drift
< 0.05% 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 flow 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:
“0.00 % CO2”. The mA current output corresponds to the monitoring level and range of 0-100% FS = 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 CO2gas 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% of full-scale range of CO2. “AUTO SPAN”
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.7
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..
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: “CO2 RANGE 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 @ #.##%”
* Identification of the RS-485 ID number setting. The menu item appears as: “485 ID SET @ ##”
* Sensor temperature in °C appears as: “TEMPERATURE ## °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% of full-scale range. For CO2gas sensors, the level is factory
set at 20% of full-scale range. The menu item appears as: “SET ALM1 @ #.##%”
3.4.3.3 Alarm 2 Level Adjustment
The alarm 2 level is also adjustable over the range 10 to 90% of full-scale range. For CO2 gas sensors, the level is
factory set at 60% of full-scale range. The menu item appears as: “SET ALM2 @ #.##%”
3.4.3.4 Calibration Level Adjustment
The Calibration level is adjustable from 10% to 90% of full-scale range. 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-640/IR-642 CO2 sensor assemblies require three conductor connection between power supplies
and host electronic controllers. Wiring designators are
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.
This wiring table is based on stranded tinned copper wire and is designed to serve as a reference only.
(4-20 mA output)
+
(DC), –(DC) , and mA(sensor signal). Maximum single
Note 3: The supply of power must be from an isolating source with over-current protection as follows:
AWG
Over-current Protection AWG Over-current Protection
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.8
22 3A 16 10A
EYS
Seal
Fitting
Drain
“T”
Plug any unused ports.
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
3.5.2 Sensor Location
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 or generation sources within the industrial process
(3) Ventilation or prevailing wind conditions
(4) Personnel exposure
(5) Accessibility for routine maintenance
A& B
(IN) and A& B(OUT).
Density
be located within 2-4 feet of grade as CO2will tend to settle in low lying areas.
Leak Sources
tions 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
manner where the migration of gas clouds is quickly detected.
Personnel Exposure
sonnel 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:
- Placement of sensors relative to the density of CO2is such that sensors for the detection of CO2should
- Most probable leak sources within an industrial process include f langes, valves, and tubing connec-
- Normal ventilation or prevailing wind conditions can dictate efficient location of gas sensors in a
- The undetected migration of gas clouds should not be allowed to approach concentrated per-
In all installations, the sensor element in SS housing points down relative to grade (Fig. 1). Improper sensor
Figure #1
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
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
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.9
Consideration should be given to easy access by maintenance personnel as well as the consequences of close prox-
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 AL M- 2 A LM -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.
M
ounting Holes
8 1/4"
6 1/8"
5
1/2"
3/4" NPT
Rainshield/
Splashguard
2"
2 1/8"
imity to contaminants that may foul the sensor prematurely.
Note:
An appropriate conduit seal must be located within 18" of the sensor assembly. Crouse Hinds type EYS2,
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 IR640-RS) is remotely mounted away from the transmitter (Model IR-640-RT).
Figure #2
a) Remove the junction box cover and un-plug the control circuit by grasping the two thumb screws and pulling outward.
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.
d) Position gold plated jumper tabs located on the connector board in accordance with desired Form C dry con-
Figure #3
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.10
tact outputs: NO = Normally Open; NC = Normally closed (see figure 3).
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
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 full-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
settings of the alarms (jumpers removed) are normally de-energized relays, non-latching relays, and alarm points
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
Figure #4
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, CO2 monitoring will
require alarms to fire in
“ASCENDING”
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 hexadecimal 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 hexadecimal table listed below. If RS-485 communications are not
used, leave the dip switches in the default position which is zero/zero (0)-(0).
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.11
gas conditions.
Figure #5
Hexadecimal 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
g) Replace the plug-in control circuit and replace the junction box cover.
3.5.6 Remote Mounting Applications
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 IR640/IR-642 sensor in a remote-mount configuration in which the sensor (Model IR-640-RS) and the transmitter
(Model IR-640-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-640/IR-642 “Fault” LED is off.
b) A reading of 0.00% CO2 should be indicated upon conclusion of a 12 second “warming up” cycle.
NOTE: All alarms will be disabled for 1 minute after power up. In the event of power failure, the alarm disable peri-
od will begin again once power has been restored.
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.12
Magnetic Programming Tool
1234
RED
BRN
WHT
BLK
Remote Transmitter
IR-640-RT
Remote Sensor
IR-640-RS
WHT
BLK
YEL
BLU
RED
BRN
56
YEL
BLU
Figure #5A
Material Requirements
* Detcon PN 3270 MicroSafe™ Programming Magnet
* Digital volt/ohm meter.
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.
Figure #6
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
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.13
detcon inc.
Program Switch #2
F
LT
ALM
1
C
AL
M
icroSafe™ CO
2
Gas Sensor
HOUS TON , TEX AS
P
GM 2
PGM 1
ALM
2
MODEL IR-640
CONTRAST
Alarm & Cal LEDs
P
rogram Switch #1
Menu Driven Display
Plug-in Microprocessor Control Circuit
Display Contrast Adjust
Figure #7
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 carbon dioxide
gas.
Material Requirements
* Detcon PN 6132 Threaded Calibration Adapter
* Span Gas 50% of full-scale range CO2in air at a controlled flow rate of 200ml/min.
a) Attach the calibration adapter to the threaded sensor housing. Apply the test gas at a controlled f low rate of
200 ml/m. Observe that the LCD display increases to a level of 20% of full-scale range or higher.
b) Remove the test gas and observe that the LCD display decreases to “0.00 % CO2”
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 CO2 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
full-scale 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 CO2gas present.
a) Enter the calibration menu by holding the programming magnet stationary over “PGM 1” (see figure 7) for 3 sec-
b) Next, enter the zero menu by holding the magnet stationary over “PGM 1” for 3 seconds until the display
onds until the display reads “1-ZERO 2-SPAN”, then withdraw the magnet. Note that the “CAL” LED is on.
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, “0.00 % CO2”.
NOTE 1: If the circuitry is unable to adjust the zero to the proper setting the sensor will enter a calibration
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.14
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: 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% of full-scale range. In this instance, a
span gas containing a concentration equal to 50% of full-scale range is required. If a span gas containing 50% of
range 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 @ x.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
x.xx% CO2” then withdraw the programming magnet. The x’s here indication the gas concentration requested.
g) Apply the calibration gas at a flow rate of 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, “0.00 % CO2”.
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).
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.15
Span calibration is complete.
3.7.3
1. Upon entering the calibration menu, the 4-20 mA signal drops to 2 mA and is held at this level until you
2. If during calibration the sensor circuitry is unable to attain the proper adjustment for zero or span, the sensor will
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.
Additional Notes
return to normal operation.
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.
3.8 STATUS OF PROGRAMMING, ALARMS, CALIBRATION LEVEL, RS-485 ID, 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 @ x.xx%”
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 @ x.xx%”
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.
3.9 PROGRAMMING ALARMS
“CO2 RANGE V6.0”
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.16
3.9.1 Alarm Levels
Both alarm 1 and alarm 2 levels are factory set prior to shipment. Alarm 1 is set at 20% of full-scale range; alarm 2
at 60% of full-scale range. Both alarms can be set in 0.01% increments from 10 to 90% of full-scale range. 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 @ x.xx%”, 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 @ x.xx%”, 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.
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.
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:
3.10 PROGRAM FEATURES
Model IR-640 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% of the full-scale range, it will cause the display to flash “OVERRANGE” 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
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.17
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
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-640/IR-642 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 –0.02%, 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
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.18
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.
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
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.19
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
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-640/IR-642 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 declassif ication of the area is required.
To adjust the display contrast, remove the enclosure cover and use a jewelers screwdriver to turn the contrast
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.20
adjust screw located beneath the metallic face plate. The adjustment location is marked “CONTRAST”. See figure 7
for location.
3.13 OPTICAL SENSOR REPLACEMENT PROCEDURE
Should the optical gas sensor element (part number 370-365878-111 or 370-287724-232) 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 370-365878-111
).
232
or 370-287724-
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.
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.21
2. Verify required DC power is applied to correct terminals.
. Swap with a known-good transmitter to determine if transmitter is faulty.
3
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
1. Check condulet for accumulated water.
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
390-000088-000 IR sensor housing assembly (plug-in detector PN370-365878-111 or 370-287724-232,
not included)
370-365878-111 Field replaceable optical plug in sensor (for .3 to 5% range)
370-287724-232 Field replaceable optical plug in sensor (for 10 to 100% range)
926-405500-RANGE IR-640 Plug-in control circuit
926-425500-RANGE IR-640 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).
Detcon Model IR-640/IR-642 Carbon Dioxide Sensor PG.22
Spash Guard
Rain Shield
Enclosure less cover
I
R Connector Board
C
ali br at io n Ad ap te r
E
nclosure glass lens cover
Plug-in control circuit
Field replaceable plug-in optical sensor
IR Sensor Housing Assembly
P
rogramming Magnet
C
ondensation
P
revention Packet
(
replace annually)
Figure #8
3.16 WARRANTY
Detcon, Inc., as manufacturer, warrants each NDIR optical plug in sensor (part no. 370-365878-111 or 370-287724-
232), for a pro-rated five year period under the conditions described as follows: The warranty period begins on the
date of shipment to the original purchaser and ends five 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 five 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-640/IR-642 Carbon Dioxide Sensor PG.23
NORMAL
OPERATION
CALIBRATION
PGM1 (3) PGM2 (3)
PGM1 (M) PGM2 (M)
PGM1 (3)
SET ALM1 @ ##%
INC
DEC
PGM1 (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
S
ET ALARM 1 LEVEL
CO2 RANGE V#.#
PGM1 (3) PGM2 (M)
V
IEW PROG STATUS
ALM1 SET @ ##%
ALM2 SET @ ##%
PGM1 (M) PGM2 (M)
PGM1 (3)
SET ALM2 @ ##%
INC
DEC
PGM1 (3) PGM2 (M)
S
ET ALARM 2 LEVEL
PGM2 (3) PGM2 (3) PGM2 (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)
PGM2 (30) PGM2 (M)
ALARM RESET
ALARM RESET
485 ID SET @ #
OPT IC S AT ##%
TEMPERATURE ##∞C
PGM1 (M) PGM2 (M)
PGM1 (3)
CAL LEVEL @ ##%
INC
DEC
PGM1 (3) PGM2 (M)
S
ET CAL LEVEL
PGM2 (3)
phone 888-367-4286, 713-559-9200 • fax 281-292-2860 • www.detcon.com • sales@detcon.com
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-640/IR-642 Carbon Dioxide Sensor PG.24
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