MSR ELECTRONIC PolyGard 2 SC2 User manual

INTEC Controls | 12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: [phone] & (888) GO.INTEC | inteccontrols.com
September 07, 2022 – Revision
Toxic (E-), Combustible (P-) and Infrared (I-CO2) Gases
PolyGard®2 SC2 & AT6 Sensors
User Manual
May 2022

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Table of Contents
1 General................................................................................................................................... 5
1.1 Intended Use...........................................................................................................................................5
1.2 Safety........................................................................................................................................................5
1.3 Installers‘ and Operators‘ Responsibilities......................................................................................5
1.4 Services ....................................................................................................................................................6
1.5 Limited Warranty ...................................................................................................................................6
1.6 Part Disposal ...........................................................................................................................................6
2 Functional Description ........................................................................................................... 6
2.1 General .....................................................................................................................................................6
2.2 Measuring Mode.....................................................................................................................................6
2.3 Special Mode...........................................................................................................................................6
2.4 Sensor Element.......................................................................................................................................7
A: Catalytic Sensor Element (Pellistor) for Combustible Gases ...............................................7
B: Electrochemical Sensor Element for Toxic Gases and Oxygen ............................................7
C: Semiconductor Sensor Element for Freon Gases, Ethylene and Ammonia.......................8
D: Infrared Sensor Element for Methane, Propane and Carbon Dioxide................................8
3 Installation ............................................................................................................................. 9
3.1 Mounting Instructions...........................................................................................................................9
3.2 Mounting of Sensors .......................................................................................................................... 10
4 Electrical Connection ........................................................................................................... 11
4.1 Plug Connection (SC2) in DT6, DC6, SGC6, SCM6 ....................................................................... 11
4.2 Terminal Connection (AT6)............................................................................................................... 11
4.3 Registration of the Sensors SC2/AT6............................................................................................. 11
5 Commissioning..................................................................................................................... 12
5.1 General .................................................................................................................................................. 12
5.2 Required Instruments for Commissioning (Calibration)............................................................ 12
6 Calibration............................................................................................................................ 12
6.1 Run-in Time .......................................................................................................................................... 13
6.2 Calibration Work ................................................................................................................................. 14
6.2.1 Zero Calibration.................................................................................................................... 14
6.2.2 Gain Calibration.................................................................................................................... 14
6.2.3 Calibration (Gain) with Surrogate Gas for Catalytic Sensor Element (Pellistor)... 15
6.2.4 Extended Calibration for Semiconductor Sensor Element ........................................ 15
6.3 Calibration Analog Output................................................................................................................ 15
6.4 Exchange of Sensors .......................................................................................................................... 16
6.4.1 Sensor SC2............................................................................................................................. 16
6.4.2 Sensor AT6............................................................................................................................. 16
6.4.3 Perform Function Test......................................................................................................... 16
INTEC Controls | 12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: [phone] & (888) GO.INTEC | inteccontrols.com
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SC2-AT6 – UserManual

7 Inspection and Service.......................................................................................................... 17
7.1 Inspection ............................................................................................................................................. 17
7.2 Service and Calibration ..................................................................................................................... 17
8 Troubleshooting................................................................................................................... 18
8.1 Indications for the SC2 ...................................................................................................................... 18
8.2 Indications for the AT6 ...................................................................................................................... 18
9 Specifications....................................................................................................................... 18
9.1 General .................................................................................................................................................. 18
9.2 Digital Sensor SC2 .............................................................................................................................. 19
9.3 Analog Sensor AT6.............................................................................................................................. 19
9.4 Sensor Element.................................................................................................................................... 20
A: Catalytic Sensor Element (Pellistor) for Combustible Gases ............................................ 20
B: Electrochemical Sensor Element for Toxic Gases and Oxygen ......................................... 20
C: Semiconductor Sensor Element for Freon Gases, Ethylene and Ammonia.................... 23
D: Infrared Sensor Element for Methane, Propane and Carbon Dioxide............................. 24
10 Figures.................................................................................................................................. 25
List of Abbreviations .............................................................................................................. 26
Glossary..................................................................................................................................... 27
Revision List............................................................................................................................. 27
INTEC Controls | 12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: [phone] & (888) GO.INTEC | inteccontrols.com
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SC2-AT6 – UserManual

1 General
It is important to read this user manual thoroughly and clearly in order to understand the information
and instructions. The PolyGard®2 devices must be used within product specification capabilities.
Due to on-going product development, MSR-Electronic GmbH | INTEC Controls reserves the right to
change specifications without notice. The information contained herein is based upon data
considered to be accurate. However, no guarantee is expressed or implied regarding the accuracy
of these data.
1.1 Intended Use
The PolyGard®2 sensors are designed for the measurement of combustible, toxic gases and oxygen
as well as of refrigerants.
The digital PolyGard®2 SC2 sensor can only be operated in conjunction with the sensor boards on
DT6, DC6, SGC6, and SCM6 of the PolyGard®2 series, as the SC2 sensor is supplied with 5 V DC
by the sensor board and the data is transmitted digitally to the sensor boards via the local
bus. The SC2 is mounted on the housing of the sensor board.
The analog PolyGard®2 AT6 sensor is operated with 24 V DC and outputs an analog 4–20 mA stand-
ard signal. The individual AT6 sensor head can be mounted on all sensor boards with analog
input, or remotely on its own housing.
The PolyGard®2 sensors must not be used in potentially explosive atmospheres. The sensor must
only be employed in areas within the environmental conditions as specified in the Technical Data.
1.2 Safety
The operating instructions must be carefully read and followed by all persons who install, use,
maintain and check the product. The product can only fulfil its intended functions if it is installed,
used, maintained, serviced and checked in accordance with the instructions provided by MSR-
Electronic GmbH | INTEC Controls.
1.3 Installers‘ and Operators‘ Responsibilities
It is the installer’s responsibility to ensure that all PolyGard®2 devices are installed in compliance
with all national and local codes and OSHA requirements. Installation should be implemented only
by technicians familiar with proper installation techniques and with codes, standards and proper
safety procedures for control installations and the latest edition of the National Electrical Code
(ANSI/NFPA70).
The equipotential bonding required (also e.g. secondary potential to earth) or grounding measures
must be carried out in accordance with the respective project requirements. It is important to ensure
that no ground loops are formed to avoid unwanted interference in the electronic measuring
equip-ment.
It is also essential to follow strictly all instructions as provided in the user manual.
INTEC Controls | 12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: [phone] & (888) GO.INTEC | inteccontrols.com
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SC2-AT6 – UserManual

1.4 Services
It is recommended to check the PolyGard®2 devices regularly. Due to regular maintenance any per-
formance deviations may easily be corrected. Re-calibration and part replacement in the field may
be implemented by a qualified technician and with the appropriate tools. Alternatively, the easily
removable plug-in sensor with the sensor element may be returned for service to INTEC Controls.
1.5 Limited Warranty
MSR-Electronic GmbH | INTEC Controls warrants the PolyGard®2 sensors for a period of one (1) year
from the date of shipment against defects in material or workmanship. Should any evidence of
defects in material or workmanship occur during the warranty period, MSR-Electronic GmbH |
INTEC Controls will repair or replace the product at their own discretion, without charge. This
warranty does not apply to units that have been altered, had attempted repair, or been subject to
abuse, accidental or otherwise. The warranty also does not apply to units in which the sensor
element has been overexposed or gas poisoned. The above warranty is in lieu of all other express
warranties, obligations or liabilities.
This warranty applies only to the PolyGard®2 devices. MSR-Electronic GmbH | INTEC Controls shall
not be liable for any incidental or consequential damages arising out of or related to the use of the
PolyGard®2 devices.
1.6 Part Disposal
Within the EU, in accordance with Directive 2012/19/EU, the device must not be
disposed of as municipal waste. Return the device for disposal to your national sales
organization, which you can contact if you have any questions about disposal.
Outside the EU, you have to consider the corresponding directives.
2 Functional Description
2.1 General
The Sensor includes a µController for measurement value processing in addition to the gas sensor
element and the measuring amplifier. All data and measured values of the sensor element are stored
in a fail-safe way in the µController and are transferred via the digital interface to the sensor board.
The calibration management is also integrated in the µController (microprocessor) of the sensor.
The sensor SC2 is connected to DT6, DC6, SGC6, or SCM6.
The sensor AT6 works according to the same principle as the SC2 series with the exception that the
AT6 outputs an analog signal of 4–20 mA (2–10 V as an option).
2.2 Measuring Mode
See description of the DT6, DC6, SGC6, SCM6 devices
2.3 Special Mode
See description of the DT6, DC6, SGC6, SCM6 devices
INTEC Controls | 12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: [phone] & (888) GO.INTEC | inteccontrols.com
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SC2-AT6 – UserManual

2.4 Sensor Element
A: Catalytic Sensor Element (Pellistor) for Combustible Gases
The integrated sensor works according to the catalytic bead principle. The ambient air to be moni-
tored diffuses through the opening into the sensor. Here the combustible gases and vapours are
burned catalytically at a heated detector (Pellistor). The resulting combustion heat also heats up the
detector. This heating changes the resistance of the detector which is proportional to the concentra-
tion of the combustible gases.
In addition to the catalytic detector, the sensor also has a similarly heated inactive compensator.
Both components are part of a Wheatstone measuring bridge. Environmental influences such as tem-
perature, air humidity or thermal conductivity of the ambient air to be monitored affect both com-
ponents to the same extent so that these influences have no significant effect on the measuring
signal.
The ageing process is accelerated by the high temperatures that occur during the combustion of the
measuring gas. Therefore, a calibration of Zero and Gain must be carried out at regular intervals (see
chapter 6).
For testing the sensor, do not use a lighter. If gassed with a lighter the sensor is unusable for meas-
urement. The warranty expires by gassing with a lighter.
B: Electrochemical Sensor Element for Toxic Gases and Oxygen
The sensor element is a sealed electro-chemical cell with 3 electrodes, sensing, reference and coun-
ter or with 2 electrodes, sensing and reference. The ambient air to be monitored diffuses through a
membrane filter into the sensor element. The chemical process of the measurement is based on a
redox reaction creating a flow of electrons that leads to a DC microampere signal between the sens-
ing and reference electrodes. This signal is linear to the volume concentration of the sensed gas. The
signal is evaluated by the connected amplifier and transformed into a linear output signal.
Electrochemical processes always lead by-and-by to a loss of sensitivity. Therefore, regular calibra-
tion of zero-point and gain is necessary. See chapter 6.
There is a small quantity of corrosive liquid in the sensor element. If in case of damage
persons or objects touch the liquid, you have to clean the affected areas as fast and care-
fully as possible with tap water. Out of use sensors must be
disposed in the same way as
batteries.
INTEC Controls | 12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: [phone] & (888) GO.INTEC | inteccontrols.com
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SC2-AT6 – UserManual

C: Semiconductor Sensor Element for Freon Gases, Ethylene and Ammonia
Semiconductor gas sensors (metal oxide sensors) are electrical conductivity sensors. The resistance
of its sensitive layer changes upon contact with the gas to be detected. The gas then reacts with the
sensor surface. This reaction is reversible in the ideal case. Due to their chemical properties metal
oxide gas sensors are suitable for a wide range of applications and the detection of all reactive gases.
Depending on the materials used and the gases to be detected, common operating temperatures
in the semiconductor sensor are between 300°C (572°F) and 900°C (1652°F). The signal is double
logarithmic to the gas concentration –not linear. The current is evaluated by the subsequent
measuring amplifier and converted into a linear output signal.
Oxidation processes lead by-and-by to an unwanted influence on the alteration of the conductivity.
Therefore, regular calibrations of zero-point (Zero) and gain are necessary (see chapter 6).
Semiconductor sensors are not linear on principle. This means that the sensor would only measure
accurately on the calibrated point and not over the entire measuring range. Therefore, a linearization
is included in our software to improve this behaviour. But since the sensor resistance of a semicon-
ductor elements may be very different, it must be normalized. This can be done via the potentiome-
ter on the PCB. Thus, the different output signals can be changed accordingly and adjusted appropri-
ately.
D: Infrared Sensor Element for Methane, Propane and Carbon Dioxide
The integrated sensor is based on the principle of the infrared absorption of gases and accomplishes
highest requirements concerning accuracy, reliability and economy. The Premium IR Sensor head is
gold-plated inside in addition and therefore offers best performance characteristics in terms of drift,
stability and reproducibility. The sensor technology uses the individual absorption spectrum of the
infrared-active molecule and determines its exact concentration through its accurate, quantitative
analysis. The infrared principle nearly eliminates the cross-sensitivity to other gases.
Due to the measuring principle, these sensors require little maintenance, but MSR | INTEC Controls
recommends regular calibration of the sensors.
For all sensor elements:
Certain substances and gases in the ambient air to be monitored can affect the sensitivity
of the sensor element or destroy the sensor completely. This is called poisoning.
The following are currently known:
•Polymerising substances, such as ethylene oxide, acrylonitrile, butadiene, styrene, silicone
and silicone vapours.
•Corrosive substances, such as halogenated hydrocarbons.
•Catalytic poisons, such as sulphur and phosphor compounds, silicon compounds, metal va-
pours.
•Organic solvents
•Oils and lubricants
INTEC Controls | 12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: [phone] & (888) GO.INTEC | inteccontrols.com
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SC2-AT6 – UserManual

3 Installation
Check the order for completeness and correctness using the delivery papers and unit la-
bels.
Electronics can be destroyed by electrostatic discharge (ESD). Therefore, the installation
work should be done only by persons connected to ground, e. g. by standing on a conduc-
tive floor or by taking appropriate grounding measures (acc. to DIN EN 100015).
3.1 Mounting Instructions
See description of the DT6, DC6, SGC6, SCM6 devices. When
choosing the mounting site please pay attention to the following:
•It is mandatory to comply with the legal requirements for the installation of gas detectors.
•The optimum mounting location may vary depending on the area of application.
•The recommended mounting height depends on the relative gas density of the type of gas
to be monitored.
Depending on the relative gas density (d), the following recommendation applies:
d < 0.90: Mount 0.3–0.5 m (about 1 ft) below the ceiling
0.90 < d < 1.10:
d > 1.10:
Mount at a height of 1.2–1.8 m (5-6 ft) above floor
Mount at a height of 0.3–0.5 m (about 1 ft) above floor
Combustible Gases Chemical Formula LEL (EU) /
% vol
Sensitivity % EU %
(Factor) /Methane
Rel. Gas Density
(Air= 1)
Acetone
(CH3)2CO
2.5
40
2.00
Ammonia
NH3
14
0.60
Petrol Vapours
n.d.
Benzene
C6H6
1.2
35
2.70
Butadiene
C4H6
1.4
50
1.92
Butyl acetate
C6H12O2
1.2
25
4.01
Cyclohexane
C6H12
1.0
50
2.90
Cyclopentane
C
5
H
10
1.4
65
2.42
Ethane
C
2
H
6
2.4
60
1.05
Ethyl acetate
CH
3
COOC
2
H
5
2.0
40
3.04
Ethanol (Ethyl alcohol)
C
2
H
5
OH
3.1
45
1.59
Ethylene
C
2
H
4
2.4
70
0.97
Iso/n-Butane
C4H10
1.4
50
2.08
Iso/n-Pentane
C5H12
1.1
45
2.49
Isobutyl alcohol
C4H10O
1.4
35
2.55
Isopropyl alcohol
(CH3)2CHOH
2.0
35
2.07
LPG
55
n.d.
Methane
CH4
4.4
100
0.56
Methanol
CH3OH
6.0
75
1.10
Methyl acetate
C3H6O2
3.1
50
2.56
Methyl ethyl ketone
CH3COCH2CH3
1.5
40
2.48
n-Heptane
C7H16
0.84
35
3.46
n-Hexane
C6H14
1.0
40
2.97
Nonane
C9H20
0.7
25
4.43
Octane
C8H18
0.8
30
3.94
Propane
C3H8
1.7
55
1.55
Propene
C3H6
1.8
1.48
Toluene
C
6
H
5
CH
3
1.0
30
3.18
Hydrogen
H
2
4.0
110
0.07
Table 1: Combustible Gases
INTEC Controls | 12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: [phone] & (888) GO.INTEC | inteccontrols.com
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SC2-AT6 – UserManual

Toxic Gases Chemical Formula Rel. Gas Density (air= 1)
Ammonia
NH3
0.60
Chlorine
Cl
2
2.48
Hydrogen chloride
HCl
1.27
Hydrogen cyanide
HCN
0.93
Ethylene
C2H4
0.97
Ethylene oxide ETO
C2H4O
1.56
Formaldehyde
CH2O
1.04
Carbon dioxide
CO
2
1.53
Carbon monoxide
CO
0.97
Ozone
O3
1.66
Oxygen
O2
1.11
Sulphur dioxide
SO2
2.73
Hydrogen sulphide
H2S
1.19
Nitrogen dioxide
NO
2
2.80
Hydrogen
H
2
0.07
Table 2: Toxic Gases
Freon Gases Group Product Code Calibration Gas Rel. Gas Density (air= 1)
FR % LFL
S2020
Respective Gas
>1
FR02
S2061
R23
>1
FR03
S2063
R1234yf
>1
FR04
S2064
R123
>1
FR06
S2070
R22
>1
FR07
S2077
R134a
>1
FR08
S2080
R407c
>1
Table 3: Freon Gases
•Choose mounting location of the sensor according to the local regulations.
•Consider ventilation conditions! Do not mount the sensor near the airflow (air passages, suc-
tion holes etc.).
•Mount the sensor at a location with minimum vibration and minimum variation in temperature
(avoid direct sunlight).
•Avoid locations where water, oil etc. may influence proper operation and where mechanical
damage might be possible.
•Provide adequate space around the sensor for maintenance and calibration work.
3.2 Mounting of Sensors
The Sensor is supplied in a separate package and should be installed on the housing only during
commissioning to protect it against dirt and damage.
•Check gas type, range and calibration date of the sensor.
•Define installation place on the housing and break out knockouts.
•Tighten the Sensor with M25 hexagon lock nut.
INTEC Controls | 12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: [phone] & (888) GO.INTEC | inteccontrols.com
Specifications subject to change without notice. | GA_MC2_SC2_E,2022-05-31 | USA 220907 | Page 10 of 28
SC2-AT6 – UserManual