Redline AR420-C User manual

Read before use!
Observe all safety instructions!
Keep for future reference
Operating Instructions
Gas Measuring System
AR420-C

Table of contents
1. For your safety ..................................................................................3
1.1 Safety information and tips ..............................................................4
1.2 Intended use ................................................................................5
1.3 Other dangers.................................................................................7
1.4 Qualification of personnel ..................................................................8
2. Product description ............................................................................8
2.1 Design of the gas measuring system ....................................................8
2.2 Principle of operation .......................................................................9
2.3 Technical data ..........................................................................10
2.4 Certification ................................................................................ 15
3. Transport and installation ....................................................................... 15
3.1 Transport ................................................................................ 15
3.2 Storage ...................................................................................... 15
3.3 Installation ................................................................................ 16
3.4 Electrical connection ................................................................... 17
4. Operation........................................................................................... 18
4.1 Commissioning ............................................................................ 18
4.2 Calibration .................................................................................. 19
5. Maintenance and servicing ................................................................... 20
6. Decommissioning ............................................................................ 21
7. Assortment / overview ........................................................................... 21
7.1 Product variant ............................................................................. 21
7.2 Spare parts and accessories ............................................................... 22
8. Packaging and transport .......................................................................... 23
9. Disposal ......................................................................................... 23
10.Appendix ......................................................................................... 23
10.1 Copyright .................................................................................... 23
10.2 Warranty ............................................................................... 23
10.3 Dimensions .................................................................................. 25

1. For your safety
Observe the instructions for use
Any person handling or operating the gas measuring system must first be fully familiar
with and observe these instructions for use. The gas measuring system must only be
used as described in section 1.2.
Servicing
The gas measuring system must be inspected and serviced regularly by qualified
specialists. Repairs to the gas measuring system must only be carried out by qualified
specialists. (See sections 1.4 and 5.)
Do not operate in areas subject to explosion hazards
The gas measuring system is not approved for operation in areas subject to explosion
hazards. Do not operate it in any areas where combustible or explosive gas mixtures
are likely to occur.
WARNING!
These operating instructions do not contain all the information necessary for the safe
operation of the device. Please acquaint yourself with the regulations and operator's
obligations that apply in your area. In addition to these operating instructions, for
example, you should observe and instruct others concerning the universally valid
legal and other binding regulations for the prevention of accidents and protection
against accidents.
If there is any doubt regarding the information contained in this translation, the
German wording shall apply.

1.1 Safety information and tips
A series of warnings is used in these instructions concerning some of the risks and
dangers that may occur when using the gas measuring system. These warnings
contain "signal words" designed to draw attention to the degree of danger that is to
be expected.
These signal words and the associated hazards are as follows:
DANGER!
Indicates an imminently hazardous situation which, if not avoided, will
result in death or serious injury. This signal word is to be limited to the
most extreme situations.
WARNING!
Indicates a potentially hazardous situation which, if not avoided, could
result in death or serious injury.
CAUTION!
Indicates a potentially hazardous situation which, if not avoided, may
result in minor or moderate injury. It may also be used to alert against
unsafe practices.
IMPORTANT!
Indicates information concerning use and other useful information.

1.2 Intended use
The AR420-C gas measuring system must be used exclusively for:
Measuring the concentration of a single toxic gas or vapour in air.
Measuring the oxygen concentration in air.
There is one specific electrochemical sensor built into the AR420-C gas measuring
system which specifically measures one single substance. One device can never
measure more than one substance! Please refer to the appendix to these operating
instructions for an exact specification of the built-in sensor. Standard substances
and measuring ranges please see chapter 7.
DANGER!
Danger to life due to poisoning!
The substances measured by the AR420-C gas measuring system are
poisonous to humans (exception: oxygen up to 21 or 25 vol%). It is therefore
essential that users and operators of the system ensure compliance with the
relevant legal regulations (e.g. MAC values). In the event of an increased
concentration, suitable measures must be taken to protect personnel, such
as an increased supply of fresh air, a ban on leaving machinery running
or evacuation of the plant.
DANGER!
Danger to life due to poisoning!
The electrochemical sensor inside the gas measuring system has a limited
service life. Regular function checks and services are therefore essential
(see section 5). The gas measuring system does not indicate when the
sensor has expired!
DANGER!
Danger to life due to fire and explosion!
Certain toxic gases and vapours such as CO and NH3are in addition
explosive. Explosive concentrations cannot, however, be detected with
the AR420-C measuring system as they are outside the measuring range
(several vol% instead of ppm).

WARNING!
Danger of fire and explosion due to sparks!
The AR420-C gas measuring system must not be operated in areas
subject to explosion hazards.
The air mixture that is to be measured must not contain any substances that might
contaminate the electrochemical sensor. In this case the sensor would output
measured values that are too low! Please refer to the appendix if necessary for
poisons for the sensor that is built into your device.
It is essential that the gas measuring system is installed only as described in section
3.3 and that the ambient conditions specified there (e.g. temperature limits) are
adhered to!
IMPORTANT!
The gas measuring system is a safety device and must only be repaired
by the manufacturer. Do not modify the gas measuring system and do
not reconstruct it. It might otherwise no longer measure the gas
concentration reliably.
The measuring signals from the gas measuring system must be evaluated and
further processed by the user's downstream device.
WARNING!
If the gas measuring system is used for a danger alarm, the main alarm
of the gas warning unit must be latching: If the concentration of toxic
gases/vapours increases greatly during an interruption to the power
supply, then after the power has been reinstated the measuring system
may in some circumstances no longer indicate a plausible measured
value.

IMPORTANT!
It is essential to observe the information given in these operating
instructions with regard to operation, maintenance and servicing.
Faults must be rectified immediately.
1.3 Other dangers
Despite its careful design, there remain some further dangers associated with
handling the gas measuring system. The following are known to us:
DANGER!
Mains voltage (230 V, 50 Hz).
Danger to life due to electric shock or burns.
Do not bring into contact with water.
Before opening the gas measuring system, safely disconnect the mains
voltage (safe electrical isolation).
Electrical work should only be carried out by a qualified electrician.
Only install in a voltage-free state.
DANGER!
Danger to life due to poisoning!
Certain external conditions can lead to the gas measuring system being
unable to measure an increased gas concentration that may be present,
e.g. in the event of a power failure. In this case, users and operators of
the system must ensure that suitable measures are taken to protect
personnel in accordance with legal regulations.

1.4 Qualification of personnel
Only qualified mechatronic engineers or persons with comparable training may
mount, install or commission the gas measuring system or carry out maintenance
and servicing work.
Only qualified electricians may carry out work on the electrical system. (In
Germany: according to German VDE!)
The operator must instruct all users of the system on the basis of these operating
instructions.
The minimum age is 16 years. An experienced person must supervise juveniles and
apprentices when working on the gas measuring system.
Any work that is not described in these operating instructions must be executed by
the manufacturer.
2. Product description
2.1 Design of the gas measuring system
The electrochemical (EC) sensor is mounted on a sensor holder inside an aluminium
housing and above a diffusion opening. The cable enters on the opposite side by
means of a screwed cable gland (PG11). The aluminium housing also contains the
transmitter with a signal amplifier and a 4-20 mA analogue output. The transmitter
processes and transmits the measured signals (see Fig. 1). It works on a two-wire
system.
The output signals from the gas measuring system are read and further processed
according to the customer's specifications in a downstream device.

Fig. 1: AR420-C gas measuring system.
2.2 Principle of operation
The AR420-C gas measuring system determines the concentration of a toxic gas or
vapour in the air mixture by means of a specific electrochemical sensor. Calibration
is carried out by means of a potentiometer using the relevant test gas. There is
very little or no cross sensitivity to other substances (see appendix). The measured
signals are processed and output (linear current output, 4-20 mA) as an integral
feature of the measuring system. The AR420-C has a 24 V DC power supply.

2.3 Technical data
Transmitter to all Sensors
power supply
screw terminals 2 pole
terminal voltage
current
min. 14 V DC ± 5%
approx. 30 mA
connections
2 reverse-polarity screw terminals 24 V DC± 5% and 4-20 mA
connecting cable 2x1,5² Cu + functional ground shielded cable
length 100 forward and return conductor
cable gland
for Ø 4-10mm
housing
Alloy, red
protection class housing IP 54
weight ca. 500g
dimensions housing ca. L90 x W85 x H65 mm without PG screw connection
potentiometer PS setting reinforcement (span)
testpins (+) and (-) connection of digital voltmeter
potentiometer PZ zero point setting (Zero)
only with three-electrode sensor
output
4-20 m, max. burden 500 ,
impedance 1000 
Sensor for Ammonia NH3, 0-100 ppm
gas inlet
per diffusion
measuring range 0-100 ppm NH3
measuring-principle two-elektrode electro-chemical
temperature range -10° C to +50° C
pay attention to sunlight
permissible humidity 15-90% relative humidity
non condensing
air pressure
900 to 1100hPa
longterm drift <2% signal loss/month
accuracy
<-8 to 4ppm equivalent
in clean air/20°C
reproducability < 3% of the signal
reaction time T90
<60 seconds
linearity
linear
life time, depending on
ambient conditions
>2 years in air under normal
conditions, from date of production
it is a so-called consumption
sensor

Sensor for Chlorine Cl2, 0-10 ppm
gas inlet
per diffusion
measuring range 0-10 ppm Cl2
measuring-principle two-elektrode electro-chemical
temperature range -20° C to +50° C
pay attention to sunlight
permissible humidity 15-90% relative humidity
non condensing
air pressure
900 bis 1100hPa
longterm drift <2% signal loss/month
accuracy
<-2 bis 4ppm equivalent
In clean air
reproducability < +/- 2%
reaction time T90
<60 seconds
linearity
linear
life time, depending on
ambient conditions
>2 years in air under normal
conditions, from date of production
Sensor for Chlorine Cl2, 0-20 ppm
gas inlet
per diffusion
measuring range 0-20 ppm Cl2
measuring-principle three-electrode electro-chemical potentiometer P2
temperature range -20° C to +40° C
pay attention to sunlight
permissible humidity 15-90% relative humidity
non condensing
air pressure
900 to 1100hPa
longterm drift <5% per year
accuracy
<-2 bis 4ppm equivalent
in clean air
reproducability < +/- 3%
reaction time T90
<30 seconds
linearity
< +/- 5%
life time, depending on
ambient conditions
>2 years in air under normal
conditions, from date of production

Sensor for Carbon Monoxide CO, 0-300 / 500 ppm
gas inlet
per diffusion
measuring range 0-300 / 500 ppm CO
measuring-principle two electrode electro-chemical
temperature range -10° C to +50° C
pay attention to sunlight
permissible humidity 15-90% relative humidity
non condensing
air pressure
900 bis 1100hPa
longterm drift <5% per year
accuracy
<-2 to 4ppm equivalent
in clean air
reproducability < +/- 5%
reaction time T90
<50 seconds
linearity
< +/- 5%
life time, depending on
ambient conditions
>2 years in air under normal
conditions, from date of production
Sensor for Carbon Monoxide CO, 0-1000 ppm
gas inlet
per diffusion
measuring range 0-1000 ppm CO
measuring-principle three electrode electro-chemical potentiometer P2
temperature range -20° C to +40° C
pay attention to sunlight
permissible humidity 15-90% relative humidity
non condensing
air pressure
900 to 1100hPa
longterm drift <5% per year
accuracy
<-2 to 4ppm equivalent
in clean air
reproducability < +/- 3%
reaction time T90
<30 seconds
linearity
< +/- 5%
life time, depending on
ambient conditions
>2 years in air under normal
conditions, from date of production

Sensor for Oxygen O2, 0-25 Vol %
gas inlet
per diffusion
measuring range 0-100 Vol% O2
measuring-principle two electrode electro-chemical
temperature range 5° C to +40° C
pay attention to sunlight
permissible humidity 10-90% relative humidity
non condensing
air pressure
811 to 1216 hPa
longterm drift ?
accuracy <+/-1% full measuring range in clean air
reproducability ?
reaction time T90
ca.14 seconds
linearity
0,21 +/- 0,02
life time, depending on
ambient conditions
>5 years at 20°C in normal air
Sensor for Sulfur Dioxide SO2, 0- 50/100 ppm
gas inlet
per diffusion
measuring range 0-100 ppm SO2
measuring-principle two electrode electro chemical
temperature range -20° C bis +50° C
pay attention to sunlight
permissible humidity 15-90% relative humidity
non condensing
air pressure
1013hPa
longterm drift <2% pro signal/month
accuracy
0,5 ppm
In clean air
reproducability < 2% of signal
reaction time T90
<30 seconds
linearity
linear
life time, depending on
ambient conditions
>2 years in air

Sensor for Hydrogen Sulfide H2S, 0-200 ppm
gas inlet
per diffusion
measuring range 0-200 ppm H2S
measuring-principle two electrode electro-chemical
temperature range -40° C to +50° C
pay attention to sunlight
permissible humidity 15-90% relative humidity
non condensing
air pressure
1013hPa
longterm drift <2% signal loss/month
accuracy
<0,2 ppm equivalent
in clean air (+20 bis +40°C)
reproducability < 2% of signal
reaction time T90
<60 seconds
linearity
linear
life time, depending on
ambient conditions
>2 Jahre in air
Sensor for Nitrogen Dioxide NO2, 0-20 ppm
gas inlet
per diffusion
measuring range 0-20 ppm NO2
measuring-principle two electrode electro-chemical
temperature range -20° C to +50° C
pay attention to sunlight
permissible humidity 15-90% relative humidity
non condensing
air pressure
1013 hPa
longterm drift <2% signal loss/month
accuracy
0,1 ppm
in clean air
reproducability < 2% of signal
reaction time T90
<60 seconds
linearity
linear
life time, depending on
ambient conditions
>2 years in air

2.4 Certification
The gas measuring system complies with EMC Directives EN 61000-6-2 and EN
61000-6-3 and thus Directives 89/336/EEC and 92/31/EEC.
3. Transport and installation
3.1 Transport
The gas measuring system is supplied together with these operating instructions.
Please check the packaging for any damage when the product is delivered and
report any damage immediately to the forwarding agency and dealer. Do not throw
or drop. The gas measuring system may be damaged or scratched. Protect it against
wet conditions, humidity, dirt and dust.
3.2 Storage
The gas measuring system may be stored in its packaging in dry rooms at temperatures
between +10° C and +50° C. Protect it against wet conditions, humidity, dirt and
dust.

IMPORTANT!
Mount the gas measuring system on a level, firm and dry wall.
When installing, it is essential to remain within the following permissible
ambient conditions:
Ambient temperature as a rule between -10 and +50° C (see appendix).
Please bear in mind that under certain circumstances the sun can heat
up the housing considerably!
The housing must be freely accessible and visible at all times.
The gas measuring system must not come into contact with water
(splashwater, condensate)!
If mounted outdoors, therefore, the device must not be directly exposed
to the weather!
It must not be accessible to dust as this will block the diffusion opening
and cause the gas measuring system to make erroneous measurements!
The ambient air must contain no sensor poisons as these will destroy
the sensor (if necessary, see appendix).
The gas measuring system must not be installed in damp locations or
areas subject to explosion hazards. Parasitic voltages must not be
permitted to occur.
IMPORTANT!
A gas measuring system should be mounted as close as possible to the
place where it is anticipated that toxic gas or vapour might escape. A
second device should be mounted in addition at mouth height.
3.3 Installation

DANGER!
Mains voltage (230 V, 50 Hz).
Danger to life due to electric shock or burns.
Do not bring into contact with water.
Before opening the gas measuring system, safely disconnect the mains
voltage (safe electrical isolation).
Electrical work should only be carried out by a qualified electrician.
Only install in a voltage-free state.
Fig. 2: AR420-C connection diagram.
Left: Version with two-electrode sensor.
Right: version with three-electrode sensor; PE, potential earth; PS, potentiometer
span for setting the span; PZ, potentiometer zero for setting zero (three-electrode
sensor only); TP (+) (-), test pins for connecting the voltmeter; 2 polarized screw
terminals for power supply (+24 V DC) and measured signal output (4-20 mA).
3.4 Electrical connection

The gas measuring system must be connected to any downstream equipment by
means of a three-core, shielded cable (see Fig. 2) with maximum 100 cable
resistance, including go and return line. Do not lay this line next to a high-tension
power cable as there is a danger of radiated interference. The cable must be
capable of withstanding the anticipated mechanical, chemical and thermal
stresses.
The gas measuring system is connected to the electric circuit (+24 V DC) by means
of one of the two polarized screw terminals. The measured data (4-20 mA) is read
by means of the second polarized screw terminal. The system earth (potential
earth) is connected to the housing.
CAUTION!
In accordance with existing safety regulations, the gas measuring system
must only be connected to suitable power supply units that comply with
the valid technical regulations. It must be ensured that fuse protection
is provided that is suitable for the power supply units used (safe
electrical isolation)!
4. Operation
4.1 Commissioning
Before commissioning use the following list to check whether all requirements for
trouble-free operation are met:
Has the gas measuring system been installed?
Is the gas measuring system accessible and visible?
Have the ambient conditions been taken into account?
Has the gas measuring system been connected?
Has the housing been screwed down again?
Is the power supply switched on?
Are you sure that the connection cable is not laid next to high-tension power
cable?
Please bear in mind that this is a sensitive measuring instrument!

Next, carry out a test of the measured values. To do this, offer up some test gas
(concentration half measuring range, e.g. 150 ppm CO) to the diffusion opening and
read the measured value on the downstream device. If the measured value corresponds
to the concentration of the test gas ± 5% of FS (warning: allow for the tolerance of
the test gas), the gas measuring system is ready for use. Prepare a commissioning
report (see section 9.2, Warranty).
4.2 Calibration
Unscrew and remove the housing lid.
Place the digital voltmeter on test pins (+) and (-). Measuring range setting:
0 to 2 V.
Offer up zero gas (synthetic air) to the diffusion opening.
Three-electrode sensor only: turn potentiometer PZ (see Fig. 2) until the
voltmeter displays 0.4 V.
For the other sensors the voltmeter must automatically display 0.4 V ± zero
tolerance 3% of FS. If not, the system is not ready for operation (e.g. short
circuit, cable break, faulty sensor).
Remove zero gas.
Offer up test gas with a concentration of 50% FS to the diffusion opening.
Turn potentiometer PS until the voltmeter displays a voltage of 1.20 V.
Remove test gas and voltmeter.
Screw down the housing lid.
Offer up the same test gas to the diffusion opening once more.
Check the measured value on the downstream equipment. (Measured signal
output: 12 mA)
If the measured value is correct, remove the test gas.
The gas measuring system is calibrated.

5. Maintenance and servicing
IMPORTANT!
The gas measuring system is a safety device and must only be repaired
by the manufacturer.
Do not modify the gas measuring system and do not reconstruct it. It
might otherwise no longer measure the gas concentration reliably.
DANGER!
Mains voltage (230 V, 50 Hz).
Danger to life due to electric shock or burns.
Do not bring into contact with water.
Before opening the gas measuring system, safely disconnect the mains
voltage (safe electrical isolation).
Electrical work should only be carried out by a qualified electrician.
Only install in a voltage-free state.
The gas measuring system and the connecting cable must be checked at least every
six months by qualified personnel (see section 1.4) and a servicing report must be
prepared. Always ensure that the interval between services meets safety requirements!
Check the measured values after each period of non-use or interruption of
operation (see section 4.1). If the measured value of the concentration of the test
gas corresponds to ± 5% of FS (warning: allow for the tolerance of the test gas), the
gas measuring system is ready for use again. If the measured value is outside this
range, please calibrate the device (see section 4.2). If this does not work, then the
gas measuring system is not functioning correctly. Inform the manufacturer or dealer
and have the device repaired.
Carry out appropriate checks to ensure that the gas measuring system and its
environment are always clean, accessible and visible. Above and beyond such
measures the gas measuring system is maintenance-free.