COMAC CAL CALOR 38 Use and care manual

CALOR 38
Ver.2.00
Installation and technical conditions
Date of issue 06/01/2022
Contents:
Description of the device ....................................................................................................................... 4
Scope of delivery ................................................................................................................................ 4
Storage conditions ................................................................................................................................. 4

CALOR 38 manual Page 2 (total 47) COMAC CAL s.r.o.
Warranty ................................................................................................................................................ 4
Installation in pipeline .......................................................................................................................... 5
Important information for selection of location ................................................................................. 5
Sources of disturbances ...................................................................................................................... 5
Installation examples .......................................................................................................................... 6
Actual installation in pipeline............................................................................................................. 7
Installation check .............................................................................................................................. 14
Wiring .................................................................................................................................................. 15
Important information ...................................................................................................................... 15
Installation of the meter's separated evaluation unit ........................................................................ 16
Meter wiring ..................................................................................................................................... 16
OUT1 / OUT2 .................................................................................................................................. 17
Impulse output / FlowSwitch / Status ....................................................................................... 17
Current output................................................................................................................................... 19
External button for resetting the user volume Vnull ........................................................................ 20
Data output ....................................................................................................................................... 20
Protection degree .............................................................................................................................. 20
Replacement of the fuse in the meter ............................................................................................... 21
Wiring check .................................................................................................................................... 21
Putting into operation.......................................................................................................................... 23
CALOR 38 OPERATING INSTRUCTIONS ..................................................................................... 24
Basic button functions ...................................................................................................................... 24
Special button functions ................................................................................................................... 24
Password setting ............................................................................................................................... 24
Basic menu ....................................................................................................................................... 25
Meter settings ................................................................................................................................... 26
Disassembly and assembly of PCB ..................................................................................................... 37
Technical data ..................................................................................................................................... 38
Factory settings .................................................................................................................................... 40
Table with flow ranges for individual DN sizes ................................................................................. 41
Basic sensor sizes ................................................................................................................................. 42
Nomogram for quick design of the measuring point ......................................................................... 44
Reduction of DN piping....................................................................................................................... 44
Faults during measurement ................................................................................................................ 45
Flow sensor cleaning ........................................................................................................................... 45
Servicing .............................................................................................................................................. 46
Ordering code ...................................................................................................................................... 46

CALOR 38 manual Page 3 (total 47) COMAC CAL s.r.o.
Form for returning the meter to COMAC CAL s.r.o. ........................................................................ 47

CALOR 38 manual Page 4 (total 47) COMAC CAL s.r.o.
Description of the device
The CALOR 38 heat 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 sensed by two electrodes which have
direct contact with the measured medium and evaluated in the electronic unit, taking into account the
temperature difference of the paired resistance temperature sensors on the supply and return pipes.
CALOR 38 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, in agreement with the manufacturer).
Meters are designed for measurements 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.
Scope of delivery
The accessories vary according to flow sensor versions and above standard optional features.
Threaded construction
Electronic evaluation unit with the fixing bracket for wall mounting (not for the compact construction),
the flow sensor (in case of the compact construction, the electronic unit is an integral part of the
temperature sensor), paired resistance temperature sensors, connecting grounding cable, installation
manual.
Flanged construction
Electronic evaluation unit with the fixing adapter for wall mounting ( not for the compact construction),
flow sensor (in case of the compact construction, the electronic unit is an integral part of flow sensor),
paired resistance temperature sensors, connecting grounding cable, installation manual.
In case of the separated construction, a special cable for connection of the meter (it must not be
extended or cut short) is part of the flow sensor.
Storage conditions
The temperature during shipment and for storage must be within the range of -10 °C up 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 separated
construction during transportation! Use slings and place them round both process connections for
transportation of meters up to DN150 (chains may damage the meter head)! Use only the holes between
the flange and sensor body for transportation, lifting and installation of the sensor in piping for DN200
and bigger!!!
Warranty

CALOR 38 manual Page 5 (total 47) COMAC CAL s.r.o.
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.
Installation in pipeline
Important information for selection of location
!!! In case of the separated construction, the cable must not be extended or cut short !!!
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.
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/s. There must be a
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

CALOR 38 manual Page 6 (total 47) COMAC CAL s.r.o.
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.
The function of empty tube detection in horizontal mounting position
operates correctly only if the evaluation unit is oriented upwards (see Fig.
below). Alternatively, it is not possible to ensure that the activation of
empty tube detection in case of partly filled or empty pipes will take place.
Due to the principle, it is necessary that the maximum
conductivity of medium is 6000 µS for ensuring the
functional evaluation of empty tube. If the conductivity of
medium is beyond the permissible range, the meter may,
despite the flooded system, register empty pipeline and the
measurement will not start.
In case of any intervention in the measuring circuit, it is necessary to consider the piping system as
being filled up with medium regardless of the state of the test indicated by the empty tube on the meter’s
display!!!
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
Free inlet or outlet Pumps
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
Build in the U-shaped pipeline
The flow meter must not be installed
in the suction side of the pump
Bubbles are accumulated in the
pipeline; erroneous measurement

CALOR 38 manual Page 7 (total 47) COMAC CAL s.r.o.
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.
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 (min.30d 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 sensor 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.

CALOR 38 manual Page 8 (total 47) 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 (in case of separated
construction, by the sensor terminal box), 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 CALOR 38 meters can be installed and operated in a horizontal
position with an upside-down oriented indicator (H ↑) and in a
vertical position with a bottom-up flow direction (V ↑) with a side-
mounted indicator. In case of horizontal piping, it is necessary to
make sure that the sensor is installed with its measuring electrodes
in horizontal position. In case of the earthing electrode
construction, possibly with testing for empty pipeline, then the
installation is always performed with the earthing reference
electrode facing down (with the sensor terminal box, eventually
with the evaluation unit facing upwards). Then the earthing
reference electrode is in the bottom position and the empty tube
sensing electrode is in the top position of the flow sensor.
Every time when the empty tube testing electrode is not covered with a liquid for 5s at least, the flow
meter will display the "Empty tube" status, and if it is necessary, it sends out an error message and
stops taking measurement. The measurement accuracy is maintained in this way. Once the electrode is
covered with the liquid again, the error message disappears and the flow meter starts taking
measurement again.

CALOR 38 manual Page 9 (total 47) COMAC CAL s.r.o.
Measurement error due to incorrect installation position
1) correct installation (evaluation unit is positioned perpendicular upwards)
EMPTY TEST – ON EMPTY TEST – OFF
2) Incorrect installation (evaluation unit is positioned diagonally, Empty test - ON)

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Installation in piping and placement of measuring electrodes in flow sensor
2) in the version with an earthed electrode and/or empty piping test electrode (3/4 of the
electrode)
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 sensor
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.

CALOR 38 manual Page 11 (total 47) COMAC CAL s.r.o.
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 (EN 1092-1):
Diameter
nominal
PN 10
PN 16
DN
Screws
Tightening torque [Nm]
Screws
Tightening torque [Nm]
Rubber
PTFE/ETFE
Rubber
PTFE/ETFE
10
4 x M12
10
15
4 x M12
10
15
15
15
20
15
20
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
65
150
8 x M20
24
90
8 x M20
27
90
200
27
115
12 x M20
35
80
250
12 x M20
35
95
12 x M24
55
100
300
50
100
80
110
350
16 x M20
60
70
16 x M24
95
105
400
16 x M24
75
120
16 x M27
140
150
If you do not find your size or structure in the Torque Table, it is a special or non-standard construction.
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.

CALOR 38 manual Page 12 (total 47) 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 sealing precisely centred between the sensor and the pipeline. If the seal protrudes into
the flow profile at some point, it causes swirls and decreases the measurement quality. Use seals that
are compatible with a 5 mm thick liquid. 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 inductive sensor, high-quality protective and working earthing
is essential. The earthing line must not transmit disturbing voltages, therefore other electrical
equipment must not be earthed at the same time.
The flow sensor is equipped with a stainless M5 earthing screw with washer and nut for a good
connection between the sensor body and the two metal pipe counter flanges. The earthing cable lug is
screwed there and it should be conductively connected with the counter-flanges. On the counter-
flanges, it is recommended connecting to the welded screws or into a threaded hole. Connection under
the flange mounting bolts is not suitable as it may corrode over time and cause measurement
disturbances.
However, if it is not ensured that the counter flanges are in direct contact with the medium to be
measured and are conductive, it is necessary to use earthing rings, see below.
Earthing rings
Use in plastic piping or metal piping with inner plastic lining rolled up or pulled out to the front faces
of the pipe 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).

CALOR 38 manual Page 13 (total 47) 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/s).
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.
Resistance temperature sensors
Resistance temperature sensors Pt 500, are installed in pipes or elbow pipes that are equipped with
oblique or straight welded-on pieces with G 1/2“ thread, according to the instructions of the
temperature sensor manufacturer. Usually the sensors are built into the thermowells; the lengths of the
thermowells are chosen according to the pipe clearance. The wells are provided with G 1/2“ threads.
The temperature sensors are mounted at an angle of 45 ° against the flow direction. The temperature
sensor is sealed in the thermowell to prevent unauthorized removal.
Thermowell length selection:
For pipe diameters: - up to 40 mm - thermowell length approx. 50 mm
- 50 to 125 mm - thermowell length approx. 80 mm
- 150 to 300 mm - thermowell length approx. 150 mm

CALOR 38 manual Page 14 (total 47) COMAC CAL s.r.o.
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.
-If the name plate (serial number) on the sensor corresponds to the one on the electronics.

CALOR 38 manual Page 15 (total 47) COMAC CAL s.r.o.
Wiring
Workers performing wiring are subject to the requirements of Decree No. 50/1978 Coll. on activities
on electrical equipment!!!
When the operations described below are performed unprofessionally, the claim on warranty becomes
extinct!!!
Prior to any opening of the evaluation unit, switch off the power !!!
It should be remembered that even in the case of a separate construction, the evaluation electronic
unit and the flow sensor form an integral unit which is metrologically verified and uniquely paired. In
consequence, make sure that the serial numbers of both parts are always identical!!!
Important information
Flow sensor connecting cable
The signal cable of the separated induction flow sensor cannot be led in parallel (even partly) with the
cables for power distribution voltage or in the proximity to electric motors, electromagnets, contactors,
frequency converters and similar sources of electromagnetic interference. In unavoidable situations, it
is necessary to put the cable in an earthed iron tube. Primarily in media with a low conductivity, cable
movements and interference may result in distortion of the measured signal. The maximum length of
the cable between the sensor and the evaluation unit is 30 metres provided that the conductivity is over
50µS/cm. In case of lower conductivities, it is recommended to use the shortest possible cable length,
however, 10m max.
In case of the separated constructions, it is possible to interconnect only the sensor and the transducer
with the same serial numbers. The special cable for connecting the separate meter version must not be
extended or shortened. In case of infringement of these requirements, measurement failures and
significant inaccuracies may occur once the meters are connected.
If it is possible to expect an increased level of unwanted electromagnetic field, we do not recommend
using the separated construction. In places with strong electromagnetic interference (in the proximity
of frequency converters, electric motors, transformers, etc.), we recommend putting a line filter before
the meter in the power supply circuit.
Evaluation unit
As standard, the evaluation unit is delivered for mains power supply 230V / 50÷60Hz.
It is possible to specify DC power supply (as standard 24V AC/DC).
For securing the tightness of the evaluation unit cover, it is necessary to keep the seal intact and clean
(replace the damaged seal immediately). If the holes for cable entries are not occupied, it is necessary
to do it.
The flow meter signal outputs may only be connected to devices where accident protection is provided
by a safe low voltage and where generated voltages do not exceed the limits defined for safe low
voltage.
When powered from the 230V / 50 ÷ 60Hz mains, the meter is powered by a switch mode power supply
that may contain beat frequencies in the acoustic spectrum whereas this symptom does not indicate a
failure of the meter.

CALOR 38 manual Page 16 (total 47) COMAC CAL s.r.o.
Never make kinks on the cable and on individual conductors and do not let them cross mutually in the
terminal board area and always use a separate cable grommet for power supply.
Cover the unoccupied grommets with a piece of cable or a plastic plug (securing of tightness).
Installation of the meter's separated evaluation unit
Firstly, decide if you want to install the fixing bracket behind, or under the electronics (the bracket
with holes upward or downward). Install the fixing bracket on the meter's aluminium housing; place
the unit as required on the wall or on a structure and mark the holes in this position for the attachment
of the bracket. Unscrew the bracket and attach it to the marked location, e.g. using wall plugs and
screws. Screw down the electronics on to the fixing bracket and connect the sensor cable using the
connector. Attach the cable to the wall or to the structure so that it does not "dangle" from the
connector. Under the connector, create a “drip loop” downwards so that water cannot trickle onto the
connector. Fix the conductors for power and the outputs in a similar way. After installation of all cables,
turn the electronics to the required position and fix the unit to the bracket by tightening the fastening
nut.
The PANEL (P) – this design is modified for building in panel areas, ideally into door, etc. where
Built-in installation is desirable.
The installation of the evaluation unit is carried out by cutting a 110x110mm square opening with an
overall area considered for the 140x140mm unit. Remove the square frame from the unit whereas the
sealing is left on the unit. After pulling the unit through the installation opening, put on the frame
from the rear side and tighten it with four inserted screws in the lateral holes so that the unit is
stabilized and prevented from a possible displacement.
*The necessary mounting depth, including the cable connector from the flow sensor is 200mm
Meter wiring

CALOR 38 manual Page 17 (total 47) COMAC CAL s.r.o.
The evaluation unit consists of two assemblies:
Front PCB with display unit Input/Output PCB along with power supply
Evaluation unit terminal board wiring:
Terminal No. 1, 5 – temperature sensor THIGH (red wires)
Terminal No. 2, 6 – temperature sensor THIGH (white wires)
Terminal No. 3, 7 – temperature sensor TLOW (red wires)
Terminal No. 4, 8 – temperature sensor TLOW (white wires)
Terminal No. 90 – current output 4÷20 mA ( + )
Terminal No. 91 – current output 4÷20 mA ( - )
Terminal No. 50 – ( C ) Out1-Imp/FlowSwitch
Terminal No.51 – ( E ) Out1-Imp/FlowSwitch
Terminal No. 20 – ( A ) RS485 communication
Terminal No. 21 – ( B ) RS485 communication
Terminals No.52 – ( E ) Out2-Imp/FlowSwitch/Status/Error
Terminals No. 53 – ( C ) Out2-Imp/FlowSwitch/Status/Error
Terminal No. 54 – external button - resetting the user energy register Enull
Terminal No. 55 – external button - resetting the user energy register Enull
Terminal No. 56 – GND for output voltage 16 V/100 mA
Terminal No. 57 – output voltage 16 V/100 mA (power supply for changing to active current
and impulse outputs)
Terminals L, N, PE – supply voltage 230 VAC
(Install as an independent supply circuit with its own protection 0.5÷1 A)
OUT1 / OUT2
Impulse output / FlowSwitch / Status
Outputs OUT1 and OUT2 are freely configurable and are realized by an optocoupler with an NPN
switching transistor. Limit parameters of this optocoupler are 80V/50mA/100mW max. The output can
be connected to operate in a passive or in an active mode when using terminals 56 and 57. In active

CALOR 38 manual Page 18 (total 47) COMAC CAL s.r.o.
mode, the meter takes advantage of internal galvanically isolated 16V power supply. In this case, the
switching voltage for log.1 level is 16V with the recommended current draw due to the optocoupler
transmission approx. 2.5mA.In the open state, the output is in the high impedance state and it is
therefore necessary to use a pull-down or pull-resistor to define the normal level.
Configuration:
1) The impulse output of energy or volume is used for remote transmission of energy or volume
impulses. The conversion constant is arbitrarily settable using buttons or user software. The
setting must be made so that the frequency does not exceed fout <400Hz.
2) FlowSwitch is used to monitor the flow value. When the set limit flow is exceeded, the contact
changes (closes/opens). The level of contact-making and contact-breaking is different – it is a
contact with hysteresis. The hysteresis is adjustable in %.
3) The status output is used to evaluate the status of the meter – fault, warning, fault + warning.
Wiring connection examples – passive output: Terminal board wiring connection:
Connection example – active output: Terminal board wiring connection:

CALOR 38 manual Page 19 (total 47) COMAC CAL s.r.o.
Considering that CTR≈100% and If=2.5mA, it is advisable to select the collector current up to
2.5mA.
Current output
The D/A converter of the CALOR 38 evaluation unit is 16-bit with data recovery performed
approximately every second. The converter is isolated from the meter by optocouplers.
If the current output is passive, it is necessary to feed the current output from an external power supply.
External power supply Ue can be 12  24 V.
The loop resistance must not be higher than R = Ue / 0,02 (Ω;V).
By default, it is set so that at maximum flow Qmax or power Pmax the loop current is 20mA and at
zero or minimum flow/power the loop current is 4mA. The borders can be set by buttons or user
software for all flow directions. In case of loss of power for the meter, it is indicated by 0mA current
loop output.
In case of active current loop, an internal 16V galvanically isolated power supply is used in FLOW38
meter.
Current loop wiring connection example:
Passive current loop Terminal block wiring connection:
Active current loop Terminal board wiring connection:

CALOR 38 manual Page 20 (total 47) COMAC CAL s.r.o.
External button for resetting the user volume Vnull
External zeroing (Reset)
The reset of the user energy counter is performed on the external input PIN54 and PIN55. The input is
isolated by an optocoupler. Simply connect an external reset button to terminals 54 and 55.
Jumper and terminal board wiring connection:
Data output
The meter can also be provided with RS485 communication with M-Bus protocol as per EN 1434-3 or
ModBus RTU.
Protection degree
The meters meet all the requirements for IP 65 protection degree. In order to ensure IP 65 protection
after installation in the plant or after a service intervention, the following must be met:
-The "O" rings inserted in sealing grooves must be clean and intact.
-If necessary, the "O" rings should be dried, cleaned or replaced with new ones.
-Screw caps must be tightened properly.
-Cables used for connection must have their outside diameters according to cable entries used.