COMAC CAL FLOW 33Exia MGD Use and care manual

FLOW 33Exia MGD
1.10
Installation and technical conditions
Date of issue 12/12/2016

FLOW 33Exia Manual Page 2 (total 33) COMAC CAL s.r.o.
Contents:
Description of device .............................................................................................................................3
Scope of delivery................................................................................................................................3
Storage conditions.................................................................................................................................5
Warranty................................................................................................................................................5
Installation in pipeline ..........................................................................................................................6
Important information for selection of location.................................................................................6
Sources of disturbances......................................................................................................................6
Installation examples..........................................................................................................................7
Actual installation in pipeline ............................................................................................................8
Installation check..............................................................................................................................13
Wiring ..................................................................................................................................................14
Meter wiring.....................................................................................................................................14
Wiring check ....................................................................................................................................17
Putting into operation .........................................................................................................................18
Technical data .....................................................................................................................................20
Safety information...............................................................................................................................22
Factory settings....................................................................................................................................24
Table with flow ranges for individual DN sizes .................................................................................25
Basic sensor sizes.................................................................................................................................26
Nomogram for quick proposal of the measured place.......................................................................30
Reduction in DN pipe..........................................................................................................................30
Failures and their symptoms during measurement ...........................................................................31
Flow sensor cleaning...........................................................................................................................31
Service..................................................................................................................................................31
Order code............................................................................................................................................32
Form for returning the meter to COMAC CAL s.r.o.........................................................................33

FLOW 33Exia Manual Page 3 (total 33) COMAC CAL s.r.o.
Description of device
The FLOW 33Exia meter is based on measurement principle by a well-known Faraday's
electromagnetic induction law according to which an electric voltage is induced during the flow of a
conductive liquid through the flow meter magnetic field. This is picked up by two electrodes in direct
contact with the measured medium and evaluated in the electronic unit.
The FLOW 33Exia type of induction meters are suitable exclusively for measurement of volumetric
flow of electrically conductive liquid substances with a minimum conductivity of 20 S/cm (at a
lower conductivity, upon agreement with the manufacturer).
Meters are designed for flow measurement where the velocity of liquid is in the range of 0.01 ÷ 12
m/s. The best measurement accuracy can be obtained in the range of 1 ÷ 10 m/s.
Flow 33Ex are firmly integrated in the pipe system of underground mine, chemical or other
application where exist the risk of explosive gases and dusts. They are formed by corundum
measuring pipe in diameter DN 15, DN 25, DN 32, DN 40, DN 50, DN 65 and DN 80 or stainless
steel measuring pipe with rubber or PTFE lining in DN15, DN 20, DN 25, DN 32, DN 40, DN 50,
DN 65, DN 80, DN 100, DN 125, DN 150 and DN 200. Pipes are inside stainless steel housing fitted
with different types of process connection. On the housing is fixed stainless steel cover for evaluation
unit with electronics of sensor, which is fitted with stainless steel top cover equipped with connector
for wiring of flowmeter to next devices.
The entire inner space of flowmeter is filled with sealing compound for protection against humidity
and increase protection against ignition of surrounding atmosphere in the hazardous area. Therefore,
after filling of the whole system is flowmeter disassembled and any changes in construction are not
possible.
Scope of delivery
Accessories vary according to the variant of flow sensor and above standard optional features.
Threaded design
Electronic evaluation unit in a compact design (the electronic unit is integral part of the flow sensor),
flow sensor, connecting grounding cable, installation manual.
Sandwich design
Electronic evaluation unit in a compact design (the electronic unit is integral part of the flow sensor),
flow sensor, bolts for installation of the sensor between flanges (quantity as per tightening torque
table, see below) with nuts and washers, connecting grounding cable, installation manual.
Flanged design
Electronic evaluation unit in a compact design (the electronic unit is integral part of the flow sensor),
flow sensor, connecting grounding cable, installation manual.
Food industry design
Electronic evaluation unit in a compact design (the electronic unit is integral part of the flow sensor),
flow sensor, adapter piping connection according to DIN 11851, installation manual.

FLOW 33Exia Manual Page 4 (total 33) COMAC CAL s.r.o.

FLOW 33Exia Manual Page 5 (total 33) COMAC CAL s.r.o.
Storage conditions
The temperature during transportation and storage of the meter must be within the range of -10 °C to
50 °C.
Wooden boards installed on the flanges in the factory are used for protection of lining on the flanges
during storage and transportation (for PTFE lining). Remove these protective boards just before
installing in the pipeline!!!
Do not lift the flanged meters by the transducer head or by the connecting box of the detached design
during transportation! Use slings and place them round both process connections for transportation of
meters up to DN125 (chains may damage the meter head)! Use only the metallic lugs on the flange
for transportation, lifting and installation of the sensor in piping in case of DN150 and bigger!!!
Warranty
Unprofessional installation or using the induction meters (devices) may result in a loss of warranty as
well as failure to comply with installation or operating conditions according to this manual.
In case of returning the meters for inspection or repair to the COMAC CAL s.r.o. factory, enclose
please the completed form, see the last page of this manual. Without having one, we will not be able
to handle your requirement for modification or possibly repair your meter correctly and promptly.

FLOW 33Exia Manual Page 6 (total 33) COMAC CAL s.r.o.
Installation in pipeline
Important information for selection of location
Outdoor conditions
It is necessary to ensure that the flow sensor is not exposed to weather effects and that the measured
medium cannot freeze in the flow sensor as it would damage the measuring tube.
In case of outdoor location of the electronic evaluation unit, the manufacturer recommends using a
protective box or a roof to avoid direct solar exposure so that the evaluation electronics cannot get
overheated.
Operating ambient temperature (full function) from 0 °C to + 44 °C
Limited increased ambient temperature (without function) up to + 55 °C
Limited decreased ambient temperature (without function)) up to - 30 °C
Relative ambient humidity with 25 °C up to 100 %
Based on characteristic of the used components is F33 Ex placed in a group II.B with maximal
temperatue < 60 °C
Sources of disturbances
The following items rank among the most frequent sources of disturbances to the steady flow of
liquid:
Abrupt changes in pipe cross-section if not performed as a cone with an angle of 7° (where
is the angle made by bevelled walls of the pipe reduction).
Incorrectly centred sealing, low ID sealing or sealing made of soft elastic materials which are
pushed out into the interior pipe cross-section after flanges are tightened.
Anything interfering in the flow of liquid, for example thermowells, branch pipes, T-pieces,
bends, elbows, slide valves, cocks, flap valves, shut-off valves, control valves, butterfly valves
and check valves. Pipe outlets from tanks, heat exchangers and filters.
No intensive magnetic fields in the proximity of the induction flow sensor (detector) must be
present.
No sources of disturbances affecting the steady flow must be present in the straight pipeline
sections. They must be located in the piping after the flow sensor or at the farthest distance before it.
Sources of disturbances may substantially reduce the measuring range and accuracy of the flow
meters.
Vibration
We recommend supporting the connecting pipes on both sides of the meter for partial elimination of
vibrations. Levels and range of vibrations must be under 2.2 in the frequency range of 20 ÷ 50 Hz
according to IEC 068-2-34. If the pipeline is exposed to excessive vibrations (e.g. from pumps),
using compact meters is not recommended.
Actual location
The flow sensor (detector) must not be at the top position of the pipe which may be airlocked, or in
declining or even in horizontal pipelines with open ends in which air may penetrate. Impurities may
accumulate during long-term measurement of very low flow rates Q < 0.1 m/sec. There must be a

FLOW 33Exia Manual Page 7 (total 33) COMAC CAL s.r.o.
sufficient pressure in the place of flow sensor installation so that the expulsion of gas or vapour
bubbles from the liquid is avoided. Little bubbles that always occur in liquids may accumulate at any
of the electrodes and this may result in incorrect operation of the meter. Gas bubbles are expelled
also at an abrupt pressure drop. Therefore, butterfly valves and similar elements should be located
after the flow sensor. For the same reason, the flow sensor should not be placed at the suction side
of the pump. To prevent the bubbles from accumulation at a low flow in the flow sensor, it is
suitable, e.g. that the pipe is slightly ascending or that the flow sensor is located in the vertical
section of the pipeline.
It is necessary for proper function of the meter, to fill up the flow sensor with the fluid to be
measured so that erroneous readout of quantity of liquid passing through the meter can be avoided
when the pipe is empty. It is necessary to select the location of the meter in such a way that the flow
sensor aeration can be avoided. In the case of an open system, the flow sensor is placed in the
bottom position of the U-profile pipework, ensuring that the fluid will not flow out of the sensor.
In case of any intervention into the measuring circuit must be accessed like a pipe is fulfilled of
medium, and regardless of the displayed information “empty pipe test” on the meter LED !!!
Installation examples
Trouble-free and exact operation of the meter is dependent on its correct location in the system. The
most frequent methods of the placement are shown in the following figures:
Recommended installation locations Downtake pipe
Horizontally laid pipeline Long pipeline
Install an air bleed valve
after the sensor
Place the sensor in a slightly
ascending pipeline
Pipeline is
empty;
erroneous
measurement
Correct
location
Install controls and shut-off
valves always after the sensor
Bubbles are accumulated in the
pipeline; erroneous measurement

FLOW 33Exia Manual Page 8 (total 33) COMAC CAL s.r.o.
Free inlet or outlet Pumps
The flow of liquid flow in the flow sensor should be steady and free of whirling. For this reason,
straight sections of pipeline with the same ID as that of the flow meter before and after the flow
sensor (with permissible deviation of +5%). Recommended minimum length of straight sections is
5d before the flow sensor and 3d after the flow sensor where d is the inside diameter of the meter
in millimetres. The same principles apply before and after the flow sensor in case of bi-directional
flow measurement.
Recommendations
In case of whirled up flow, extend the calming sections of pipeline or integrate a flow
conditioner.
When blending a mixture of substances, it is necessary to install the flow meter either before
the point of blending or at a sufficient distance after it (30d min. where d is the inside
diameter of the meter in millimetres), otherwise it will result in instability of indication.
When plastic pipeline is used or in case of metallic pipes with internal non-conductive layer,
earthing rings are needed.
Do not install the sensor at the suction side of the pumps; this will eliminate the risk of
vacuum and possible damage to the measuring tube lining.
Pumps, bends and elbows found closely in succession in various levels should be at a distance
of 20d at least before the flow sensor. In case of a separate elbow or bend, the placement
10d before the meter is recommended.
When piston pumps, diaphragm pumps, and flexible tube pumps are used, it is necessary to
install a pulse damper in the system.
In order to provide the highest accuracy, it is important to ensure permanent flooding for the
sensor (for example, by installation of the sensor in the U-shaped pipeline) even if the sensor
is equipped with empty tube test. This will serve as an additional safety measure for detection
of non-flooded tube.
The responsibility for suitability and adequacy of application of induction flow meters is borne by
the designer or possibly the user himself.
Actual installation in pipeline
When welding both counter-flanges to the pipelines, it is necessary to maintain their alignment so
that levelness of bearing surfaces of the flanges onto the front faces of the detector is ensured (at the
same time, this must not be achieved by unequal tightening of the bolts as there is a risk of leakage
due to thermal loading in the future or the measuring tube may break during such tightening). The
difference of LMAX and LMIN distances of the sealing surfaces of the flanges before the flow sensor is
installed must not be greater than 0.5 mm.
Built in the U-shaped pipeline
The flow meter must not be installed
in the suction side of the pump
free flow

FLOW 33Exia Manual Page 9 (total 33) COMAC CAL s.r.o.
The opposition of the holes in the counter-flanges for the bolts should be ensured in the same manner
and a sufficient room behind the flanges should be available for the bolts and nuts so that the actual
installation of the sensor in pipeline and its attachment with the bolts is made possible.
The manufacturer recommends using an intermediate piece during welding. It is absolutely excluded
to use the flow sensor as an intermediate piece due to thermal damage. The welding current must not
run through the flow sensor during electrical welding. The installation of the flow sensor is carried
out after welding, coating, building and similar works are completed.
The actual installation is performed by the fixation between the counter-flanges that are welded to
the calming pipeline (5×d before and 3×d in the direction of flow) whereas the liquid must run
through the flow sensor in the direction indicated by the arrow on the sensor name plate.
During installation, do not lift the meter by the evaluation unit housing, possibly under the meter's
metallic housing but always use slings round the process connection or use the lifting lugs on the
flanges.
Installation position
The inductive flow sensor is installed in arbitrary position in vertical piping. In case of horizontal
piping, it is necessary to make sure that the sensor is installed with its measuring electrodes in
horizontal position.
Installation in piping and placement of measuring electrodes in flow sensor

FLOW 33Exia Manual Page 10 (total 33) COMAC CAL s.r.o.
During installation, beware of:
-dropping the meter onto the ground and damaging the measuring tube or electronics
-contamination of the electrodes (do not touch the electrodes, otherwise they get
contaminated)
-when additional sealing is used, avoid its interference in the flow profile of the detector
between the flanges and the pipeline, otherwise the flow measurement error may be
increased
Tightening torques
It is absolutely necessary to tighten the bolts and nuts equally by alternating sides and in the order
shown in figure applying the maximum torque according to the table.
If the bolts are tightened too much during the installation of pipework components, deformation of
the sealing surface may occur. In consequence, the torque values indicated in the table are used as a
guidance for tightening the screws and bolts.
Table with tightening torques for screws/bolts:
Diameter
nominal
PN 10
PN 16
DN
Screws
Tightening torque [Nm]
Screws
Tightening torque [Nm]
Rubber
PTFE
Rubber
PTFE
15
4 x M12
20
25
4 x M12
20
25
20
20
25
20
25
25
20
25
20
25
32
4 x M16
20
25
4 x M16
20
35
40
20
25
20
35
50
20
45
20
45
65
20
46
20
46
80
8 x M16
20
48
8 x M16
20
48
100
20
50
20
50
125
20
80
20
80
150
8 x M20
24
90
8 x M20
27
90
200
25
115
12 x M20
28
80
250
12 x M20
27
95
12 x M24
38
110
300
34
115
55
150
350
16 x M20
47
140
16 x M24
75
160
400
16 x M24
65
155
16 x M27
85
200

FLOW 33Exia Manual Page 11 (total 33) COMAC CAL s.r.o.
Diameter
nominal
PN 25
PN 40
DN
Screws
Tightening torque [Nm]
Screws
Tightening torque [Nm]
Rubber
PTFE
Rubber
PTFE
15
4 x M12
25
25
4 x M12
25
25
20
25
25
25
25
25
25
25
25
25
32
4 x M16
25
35
4 x M16
25
40
40
25
35
35
50
50
35
45
35
60
65
8 x M16
35
46
8 x M16
45
55
80
40
48
45
60
100
8 x M20
40
55
8 x M20
50
75
125
8 x M24
50
110
8 x M24
70
120
150
57
115
75
136
200
12 x M24
68
100
12 x M27
85
145
250
12 x M27
88
120
12 x M30
105
-
300
16 x M27
95
125
16 x M30
115
-
350
16 x M30
115
200
16 x M33
140
-
400
16 x M33
135
255
16 x M36
165
-
The flanged connection design corresponds to EN 1092-1.
In case of using a corundum or thermoplastic tube, the same torques apply as in case of using the
PTFE tube according to the given pressure series.
If you do not find your size or structure in the Torque Table, it is a special or non-standard design. In
such a case, contact the manufacturer for more detailed information.
It is necessary to do the tightening three times, whereas for the first time, to 50% of the maximum
torque according to the above given Table. For the second time, to 80% and for the third time, to
100% of the maximum torque. We recommend checking the screws/bolts for tightening some 24
hours after installation of the meter.
When installing the flow sensors over 200 mm, it is necessary to follow, except for the above
mentioned rules, also simultaneous tightening of parallel screws on both opposite flanges to avoid
possible damaging the electrodes or the measuring tube (symmetrical tensioning of the lining).
If the flanged joint is not tight, although all of the screws are tightened closely, these must not be
tightened more but slackened on the opposite side to the untightness and tightened on the other side.
If the untightness manifests itself even after that, it is necessary to check the sealing surfaces for
scratches or mechanical impurities. If the scratches or any other damage are deeper than some 15%
of the thickness of the flange, it is possible to remove them using fine emery paper.
In case of the threaded connection, it is necessary to check, while tightening, the screwed connection
on the sensor so that torsional displacement is be avoided.

FLOW 33Exia Manual Page 12 (total 33) COMAC CAL s.r.o.
Seal
The turned up part of the lining does not carry out the function of sealing so it is necessary to insert
the appropriate seal precisely centred between the sensor and the pipeline. If the sealing extends in
some place into the flow profile, it makes whirls and reduces the measurement quality. Use the seals
compatible with the liquid and 5mm thick. Do not use graphite or any other electrically conductive
material to hold the sealing in place during installation. It could influence the measuring signal
accuracy.
Earthing
For reliable and correct operation of the induction sensor it is necessary to provide proper protective
and working eathing. The earth line must not transmit interference voltages so the other electrical
devices must not be earthed by means of this line.
The flow sensor is provided with the M5 earthing screw of stainless steel with a washer and nut for
proper connection of the sensor body with both counter-flanges of the metallic pipeline. The earthing
cable lug is screwed there and it should be conductively connected with the counter-flanges. On the
counter-flanges, it is recommended their connection to the welded crews or into a threaded hole.
Connecting under the fixing screws of the flange is not suitable as they may corrode with time and
cause failures in measurement.
However, if it is not ensured that the counter-flanges are in dicert contact with the measured media
and they are conductive, the earthing rings must be used, refer hereinafter.
Earthing rings
Using for a plastic pipeline or in case of metallic pipelines with internal plastic lining turned up or
pulled out to the front faces of the pipeline flanges. Conductive earthing rings of stainless steel create
conductive connection with the measured substance. Usually, potential equalization is carried out by
means of the reference earthing electrode in the measuring tube. In exceptional cases, the equalizing
currents may run through the reference electrode based on the device earthing conception. This may
lead to deterioration of the sensor, e.g. by electrochemical disintegration of the electrodes. In such
cases, it is necessary to use the earthing rings for potential equalization. This holds true for two-
phase or two-component flows in which the medium is blended badly or its components cannot be
blended. In general it can be said that using the earthing rings is always the protection against stray
currents and the warranty of correct measurement at the same time.
The flow sensor is provided with the earthing screw of stainless steel for the earthing cable supplied
with the mounting accessories. Then this cable must be conductively connected with the earthing
rings.
The earthing rings are not part of our standard package and must be ordered separately. Chemical
durability of the material must correspond with the liquid to be measured; it is usually made of the
same material as the sensor electrodes. While mounting, it is necessary to insert seals in both sides
of the earthing ring and take care that no part extends to the internal profile of the sensor (whirling
and turbulence of the medium).

FLOW 33Exia Manual Page 13 (total 33) COMAC CAL s.r.o.
Electrodes
The electrode material must be selected according to chemical resistance to the liquid to be
measured. The purity of the electrodes may have an influence on measurement accuracy, their heavy
foulness may cause even the interruption of the measuring function (isolation from the liquid). It is
not necessary to clean the electrodes right after delivery before their installation in the pipeline. If the
electrodes indicate signs of foulness, clean them with a soft cloth or use a chemical cleaning agent.
Mind damaging to the lining! During routine operation, in case of a great majority of liquids, it is not
necessary to clean the flow meter for the entire operation period of the flow sensor; self-cleaning by
flow of the liquid is sufficient (recommended velocity is over 2 m/sec).
PTFE lining
Meters with PTFE lining are equipped with protective covers to prevent the sealing surfaces from
damaging during transportation or storage and from changing the shape (due to elastic memory of
the PTFE material, it is restraightened to the tube). Protective covers may be removed only right
before the installation. If these covers are removed due to a check, it is necessary to replace them
immediately.
Carry out the installation at the lowest point of the pipeline to avoid the occurrence of vacuum. Never
detach and damage the rim of the PTFE lining turned up to the of flow sensor faces. Remove the
covers from the inlet and outlet sides right before insertion of the sensor between the pipeline flanges
and replace them with metal plates (0.3 ÷ 0.6 mm thick). After insertion of the sensor, remove the
metal plates and install the screws/bolts.
Installation check
After installation of the flow sensor in the pipeline, the following must be checked:
-According to the name plate, if there is a relevant meter in the given measuring point
(pressure, temperature, dimension, etc.).
-If the direction of the arrow on the device is in agreement with the direction of the flow in the
pipeline.
-Correct position of the measuring electrodes (horizontally).
-Correct position of the electrode for empty pipeline detection (up).
-If all bolts (screws) are tightened properly.
-If earthing rings are used, then their correct installation and connection with the sensor.
-Accuracy of flow sensor earthing.
-Accuracy of execution of the pipeline calming section lengths
-If the sensor is protected against vibrations and mechanical damage.

FLOW 33Exia Manual Page 14 (total 33) COMAC CAL s.r.o.
Wiring
For use in conditions where is occurrence of explosion of gases and dust and gassy coal mines apply
the following safety parameters and standards.
Workers performing wiring are subject to the requirements of Decree No. 50/1978 Coll. on activities
on electrical equipment!!!
When the following operations are performed unprofessionally, the claim on warranty for the
resulting errors becomes extinct!!!
Prior to any manipulation with the meter, switch off the power!!!
Meter wiring
Evaluation unit
As a standard, the evaluation unit is in Ex ia design delivered for 10V (120mA) až 24V (55mA)
supply voltage.
The flow meter signal outputs must only be connected to devices where accident protection is
provided by safe low voltage and where generated voltages do not exceed the limits defined for safe
low voltage.
The power supply of flowmeter and a meter outputs (pulses, 4-20 or 0,2-1mA) are connected to a
connector, which is an integral part of the flowmeter and through which is connected to the desired
devices. During any installation works must be flowmeter disconnected from the power supply.
Standard wiring of connector on body of flowmeter
1 –power supply +
2 –power supply -
3 –output (pulses - emitor optocoupler –negative pole)
4 –output (pulses - colector optocoupler - positive pole)
5 –output (4-20mA or 0,2-1mA –negative pole)
6 –output (4-20mA or 0,2-1mA - positive pole)
(7) –grounding
Devices for group I (I M1 Ex ia I Ma)
Conecctor Amphenol C016
Devices for groups II (II 1G Ex ia IIC T6 Ga a II 1D Ex ia IIIC T85°C Da)
Connector SEALCON Signal Connector M23

FLOW 33Exia Manual Page 15 (total 33) COMAC CAL s.r.o.
Recommended connecting cables:: Lapp Kabel
Oelflex EB
Oelflex EB CY
Unitronic Li2YCY
Power supply characteristics FLOW 33 Ex ia

FLOW 33Exia Manual Page 16 (total 33) COMAC CAL s.r.o.
Pulse Output
Pulse output is realized via optocoupler with switching transistor NPN. Limited parameters of this
optocoupler are max.300V/150mA/100mW.
Pulse output is used for remote transfer volume of pulses and for the metrological verification of the
flowmeter. When you order,can be constant freely adjusted (data type float), but later modification
by the customer is not possible.
Optocoupler loading should be chosen so do not to exceed of the limited parameters:
Loading charakteristice (If = 2,5mA) Wiring example
Maximal frequence of pulse output is 800Hz with puls width min. 250µs.

FLOW 33Exia Manual Page 17 (total 33) COMAC CAL s.r.o.
4-20mA output
4-20mA output could be in two versions:
Passive: 4mA až 20mA
Active : 0,2mA až 1mA
4mA –20mA:
D/A –convertor of flowmeter FLOW33Exia is 16bite with updating dates each 80ms. Converter is
galvanically isolated by optocouplers from the flowmeter. 4-20mA output is needed to powered
from an external power. Voltage of external power Uecould be 12 až 24 V. Resistance of current
loop must not be higher than R = Ue/ 0,02 (Ω;V).
0,2mA –1mA:
D/A –convertor of flowmeter FLOW33Exia is 16bite with updating dates each 80ms. Converter is
NOT galvanically isolated from the flowmeter. Current loop is active and powered from flowmeter.
Outputs voltage Uois max. 25,2 V. Output resistance of current loop is 4700 Ω. The default
setting is that at maximum flow Qmax is 20 mA(1mA) and at zero or negative flow
4 mA (0.2 mA). The current value is proportional to the value of the flow in the
sample. Qmax(20mA nebo 1mA) is freely adjustable (float data type) when ordering the meter. In
case of failure or power loss falls down the current loop output to 0mA and can be detected faulty
status by superior system.
Example of passive wiring of current loop:
Wiring check
After completion of wiring, it is necessary to check:
-Connecting cables for damage.
-Cables for pull relief.
-Correct connection of cables to terminals.
-Whether the supply voltage corresponds with the nameplate data.

FLOW 33Exia Manual Page 18 (total 33) COMAC CAL s.r.o.
Putting into operation
Prior to connection to power supply, check the device installation accuracy in accordance with
“Installation in pipeline“ and “Wiring” chapters.
If the meter has no electrode for empty tube detection, do not connect the meter to power before
filling the system with the fluid to be measured and power off the meter before system discharge.
It is important for ceramic measuring tube, while the piping is filled with a medium, to maintain
gradual warming up or cooling down the ceramic measuring tube, always by 50°C at the most, and
after 5 minutes every time. Failure to observe these conditions may result in destruction of the
measuring tube.
If you wish the meter to take measurement as precisely as possible right after powering up, it is a
good idea to fill the flow sensor with water, one or two days before its installation, so that all of its
electrodes are flooded. Just before the installation, the water is discharged and the sensor is
installed into piping. Right after installation, piping is filled with a medium so that the electrodes
cannot dry off.
After the meter is powered up, the green LED on the top cover next to the connector is lit,
confirming the supply voltage on the control PCB and stabilization of parameters of the meter takes
place afterwards (approx. 20sec). After that period of time, the meter starts measuring.
Meter status:
It is continuously displayed by two indicator LEDs located in the evaluation unit top cover (next to
connector). The meter status indicated by the LEDs can be as follows:
LED1
LED2
Description
Current output
green
-
The meter is in good order and the flow is null or
negative
4mA
green
blue is
flashing
The meter is in good order and the flow is positive
where the blue LED is indicating the transmission of
volumetric pulses
4÷20mA
-
-
Supply voltage error
-
Flow direction:
The arrow indicates the direction liquid flow inside the sensor and thus the correct orientation of
the meter's sensor for installation in piping.

FLOW 33Exia Manual Page 19 (total 33) COMAC CAL s.r.o.
Basic parameter settings
The meter or flow meter parameters are set by the manufacturer in accordance with the purchase
order. If these values are not indicated in your purchase order, the meter will be set up using the
default parameters in accordance with the meter's range.
Measuring range boundary values
Refer to meter's nameplate
Excitation time constant
Standard 140 ms
Impulse output width /gap
Adjustable by producer (from 600µs)
Impulse output constant
fmax [800 Hz] => Qmax
Flow at 4mA current output
Meter minimum flow, refer to meter nameplate
Flow at 20mA current output
Meter maximum flow, refer to meter nameplate
Current loop - meter error status
<4mA
Application
Stable flow
Safety rules for operator
Any interventions in the inductive flow sensor and evaluation unit itself are illegal on the part of
operator and they may lead to direct scalding by medium. Perform electrical connection always after
powering off.
For use in conditions where is occurrence of explosion of gases and dust and gassy coal mines apply
the following safety parameters and standards.

FLOW 33Exia Manual Page 20 (total 33) COMAC CAL s.r.o.
Technical data
Power 10V/120mA ÷24V/55mA
Input power 1,2 ÷1,3 W
Electrical connection Connector Amphenol C016 (I M1 Ex ia I Ma)
Connector SEALCON Signal Connector M23
(II 1G Ex ia IIC T6 Ga a II 1D Ex ia IIIC T85°C Da)
Display 2× LED (meter status)
Construction compact
Max. temperature of medium 40 °C
Size DN 15÷200
Lining material rubber (hard, soft, for potable water): DN20÷DN200
PTFE: DN 15÷DN 200
Electrode material CrNi steel DIN 1.4571, Hastelloy C4, Titanium, Tantalum
Construction all-welded frame
Sensor material flanged –stainless steel and structural steel with polyurethane coating
sandwich, threaded, food processing –stainless steel
Process connection sandwich
flanged DIN (EN1092)
threaded (EN ISO 228-1)
food processing (fittings DIN 11851, clamp)
Measure range (Qmin/Qmax) unidirectional/bidirectional for 0.2÷12 m/s (1/60)
Flow meter accuracy up to 0.5 % (for 0.1 ÷ 10m/s)
Repeatability up to 0.2% (for 0.1 ÷ 10m/s)
Min. medium conductivity 20μS/cm (at a lower conductivity, upon agreement with manufacturer)
Outputs (passive) impulse (max. 1.6 kHz, selectable constant)
analogue 4÷20 mA or 0,2 ÷ 1 mA
Sampling: 800 samples per second (standard)
I/O response: 70ms (current loop)
Max. ambient temperature 55°C
Ambient humidity: max. 90%
Pressure PN10, PN16, PN25, PN40
Pressure loss negligible
Flow sensor protection IP65, IP67, IP68
Electronics protection IP65
Negative pole of powering is connected with grounding of flowmeter via safety resistor
Outputs signals of pulses and 4-20mA are passive and galvanically isolated from the electronics of
flowmeter and from power supply of flowmeter.
Output signal of current loop 0,2–1mA is active and is galvanically connected with power supply of
flowmeter.