Danfoss Heat Cost Allocator Operating guide

Operating Guide

Electronic Heat Cost Allocator

Table of Contents 1. General ..................................................................................................................................... 3

1.1 Application.......................................................................................................................................................... 3

1.2 General Guidelines........................................................................................................................................... 3

1.2.1 Hazards and Disposal .............................................................................................................................. 3

1.2.2 Changing the Battery .............................................................................................................................. 3

1.2.3 Installation with Glue .............................................................................................................................. 3

1.2.4 Warranty ....................................................................................................................................................... 3

1.2.5 Compliant Use ............................................................................................................................................ 3

1.2.6 Non-compliant Use .................................................................................................................................. 3

1.2.7 Notes regarding Installation ................................................................................................................. 3

1.2.8 Protection against Outside Influences.............................................................................................. 3

1.2.9 Data Collection while the Device is open ........................................................................................ 4

1.2.10 Transport in Original Packaging .......................................................................................................... 4

1.2.11 New Programming ................................................................................................................................... 4

1.3 Restrictions ......................................................................................................................................................... 4

1.3.1 Applications ................................................................................................................................................ 4

1.3.2 Measurement using Single or Dual Sensors ................................................................................... 4

1.3.3 Exclusion of Liability ................................................................................................................................ 4

1.3.4 Modifications .............................................................................................................................................. 4

2. Product Description ................................................................................................................ 4

2.1 Packaging ........................................................................................................................................................... 4

2.2 General Description ........................................................................................................................................ 4

2.2.1 Type ................................................................................................................................................................ 4

2.2.2 Design ........................................................................................................................................................... 4

2.2.3 Characteristics ............................................................................................................................................ 5

2.2.4 Display ...........................................................................................................................................................5

2.2.5 Electronics ................................................................................................................................................... 5

2.2.6 Versions......................................................................................................................................................... 5

2.2.7 Optical Interface ........................................................................................................................................ 6

2.2.8 Radio Wireless M-Bus .............................................................................................................................. 6

2.3 Technical data .................................................................................................................................................... 6

3. Settings .................................................................................................................................... 7

3.1 Settings ................................................................................................................................................................ 7

3.2 Operating mode ............................................................................................................................................... 9

3.2.1 Cycle ............................................................................................................................................................... 9

Operating Guide SonoHCA

Table of Contents

(continuous)

3.2.2 Single Sensor Version with Start Sensor ........................................................................................... 10

3.2.3 Dual Sensor Version ................................................................................................................................. 10

3.2.4 Comparison of the Measuring Principles ......................................................................................... 10

3.2.5 Temperature Measurement and Calculation .................................................................................. 10

3.2.6 Calculation of the Displayed Consumption Value ........................................................................ 11

3.2.7 Start of Counting ....................................................................................................................................... 11

3.3 Display and Additional Functions .............................................................................................................. 12

3.3.1 The Menu Sequences of the Digital Display................................................................................... 12

3.3.2 The Digital Display ................................................................................................................................... 12

3.3.3 Rolling Display ........................................................................................................................................... 15

3.3.4 Communication Indicator and Measuring Indicator • .......................................................... 16

3.3.5 Real Time Clock and Calendar ............................................................................................................. 16

3.3.6 Check code.................................................................................................................................................. 16

3.4 Special Functions ............................................................................................................................................. 17

3.4.1 Suppression of Summer Counting ..................................................................................................... 17

3.4.2 Annual Reset of the Consumption Value ......................................................................................... 17

3.4.3 Unit Scale and Product Scale ................................................................................................................ 17

3.5 Parameterization .............................................................................................................................................. 17

3.6 Error ....................................................................................................................................................................... 17

3.6.1 List of Errors ................................................................................................................................................. 17

4. Installation ............................................................................................................................... 18

4.1 Introduction ....................................................................................................................................................... 18

4.2 DIN Standard Requirements for the Installation .................................................................................. 18

4.3 General Restrictions ........................................................................................................................................ 18

4.4 Operating Range .............................................................................................................................................. 18

4.5 Allocator Installation Position – Standard Installation ....................................................................... 19

4.6 Mounting the Remote Sensor ..................................................................................................................... 20

4.7 Wall Mounting ................................................................................................................................................... 21

4.8 Installation of Fastening Parts Kits ............................................................................................................ 22

4.8.1 Installation to Sectional Radiator, direct mounting ..................................................................... 22

4.8.2 Sectional Radiator, wall mounting ..................................................................................................... 22

4.8.3 Installation on Folded Radiator ........................................................................................................... 23

4.8.4 Folded Radiator, wall mounting .......................................................................................................... 23

4.8.5 Installation to Panel Type Radiator ..................................................................................................... 24

4.8.6 Mounting of heat cost allocators with glue .................................................................................... 24

4.8.7 Panel Type Radiator, wall mounting .................................................................................................. 25

4.8.8 Installation to Panel-Type Radiator with Front Convection Plate ........................................... 25

4.8.9 Bathroom radiator – Towel rails ........................................................................................................... 26

4.8.10 Sectional Radiator wide .......................................................................................................................... 27

4.9 Overview mounting accessories ................................................................................................................ 27

4.10 Mounting and Sealing .................................................................................................................................... 28

5. Commissioning ........................................................................................................................28

5.1 Automatic commissioning during the installation.............................................................................. 28

5.2 Commissioning by pressing push button .............................................................................................. 29

5.3 Radio Standby ................................................................................................................................................... 29

5.3.1 Sleeping Mode ........................................................................................................................................... 30

5.3.2 Installation Mode ...................................................................................................................................... 30

5.3.3 Operation Mode ........................................................................................................................................ 30

6. Readout .................................................................................................................................... 30

6.1 Remote Radio Reading .................................................................................................................................. 31

6.1.1 General Information about the Remote Radio Readout............................................................. 31

6.1.2 WireIess M-Bus Remote Radio Readout ............................................................................................ 31

6.1.3 Readout using the Radio Central SonoCollect ............................................................................... 31

7. Rating factors ..........................................................................................................................32

7.1 Taking Measurements ..................................................................................................................................... 32

7.1.1 Rating of Radiators with Over Length or High Nominal Power ............................................... 32

7.1.2 Rating of Radiator ..................................................................................................................................... 32

7.2 Table of Rating Factors ................................................................................................................................... 33

7.3 Rating Factor according EN 834:2013 ........................................................................................................ 33

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Operating Guide SonoHCA

1. General

This manual serves as a reference for users and service personnel of the Danfoss heat cost

1.1 Application

allocators. It describes the use of the SonoHCA heat cost allocators.

The heat cost allocator is a measuring device to record the heat output of radiators in units. Units are apartments, offices, and business, commercial or industrial premises whose heat is supplied through a central heating system or via a conjoint district heating station.

The group of units constitutes one billing unit.

If one billing unit includes units with differences, for example, from a technical standpoint (in the form of different heating systems) or in terms of consumption behaviour (i.e. in the case of industrial premises and apartments), a subdivision of the billing units into unit groups may be necessary.

Each radiator is fitted with a heat cost allocator which records and assesses the heat output of the radiator and displays the consumption value.

1.2 General Guidelines 1.2.1 Hazards and Disposal

The heat cost allocators a re equipped with

respect the transpor t directives applicable in yo ur coun try.

lithium batteries . This type of batte ry falls into the category of ha zardous goods. Please

Handling of Lithium Batteries:

• Store in a dry place.

• Do not heat to more than 100°C and do not

throw into a fire.

• Do not store near a heat source.

• Do not store in direct sunlight.

• Do not short-circuit.

• Do not open or damage.

• Do not recharge.

• Keep out of reach of children.

1.2.2 Changing the Battery

The heat cost allocator’s battery is soldered. Changing the battery is neither provided for nor permitted.

Disposal

In order to protect the e nvironment, to

reduce waste of natural resources and prevent pollution, the European Uni on

has adopted a directive stipulating that electric al and electronic devices must be recovered by their manufac turers in order to ensure proper destruction or recycling.

Should you dispose of the device yourself, please get information from your local authority on recycling options.

The consumption value is the basis for allocating the heating costs to each unit, which is necessary for the annual billing of the heating costs.

The heat cost allocators are principally used in the following units:

• Collective housing buildings.

• Offices or administrative buildings.

The typical users are:

• Measuring and billing services.

• Cooperatives or property managers.

• Building service companies, letting agencies.

The heat cost allocators can be installed on:

• Sectional radiators.

• Column/tube radiators.

• Panel radiators with horizontal or vertical

water flow.

• Flat register radiators.

• Convector heaters.

1.2.4 Warranty

The warranty rights are only valid if the devices have been installed and used in compliance with regulations and if the technical guidelines in force have been followed.

1.2.5 Compliant Use

Installation of this product must comply with the installation directives described in this manual and carried out by personnel trained for this purpose.

1.2.6 Non-compliant Use

Any application other than that described above is not permitted.

1.2.7 Notes regarding Installation

Any inappropriate handling or faulty installation may result in radiator leakage. Please respect the recommendations of the installation notice for the radiator.

1.2.8 Protection against Outside Influences

1.2.8.1 Lead seal

The heat cost allocator is closed with a safety seal which cannot be removed without causing damage. It is therefore impossible to open the device without this being detected. After installation, the electronic part of the device is no longer accessible. The LCD display, the push button and the optical itnterface are protected. It is impossible to access the interior of the device without damaging it.

1.2.3 Installation with Glue

Due to their chemical composition, the use of glues emits vapours and can damage the plastic casing of the heat cost allocator.

1.2.8.2 Electronic Detection of Opening

The electronic detector detects unauthorised opening and closing of the heat cost allocator. As soon as the housing of the heat cost allocator

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Operating Guide SonoHCA

1.2 General Guidelines

(continuous)

1.3 Restrictions

is opened and / or removed, the electronic detector triggers an error message. During this time, the date of opening of the case, the number of openings and the cumu-lative length of time for which the case was open are saved and may be read using the optical interface or the radio.

1.2.9 Data Collection while the Device is open

The heat cost allocators continue to collect data, even if the electronic detector is activated.

1.3.1 Applications

The heat cost allocators may not be used in the following cases:

• Steam heating.

• Air radiators.

• Floor heating.

• Ceiling radiant heating.

• Flap-controlled radiators.

• Radiators with a removable front plate

(attached with clips).

Heat cost allocators may only be attached to radiators controlled by a combination of flaps and valves if the control is disassembled or locked in the ‘open’ position.

1.2.10 Transport in Original Packaging

The heat cost allocators must be transported in their original packaging.

1.2.11 New Programming

Before each new instance of programming, save the history of previous value readings.

1.3.2 Measurement using Single or Dual Sensors

Combining the two systems in the same building or in a single calculation unit is not permitted.

1.3.3 Exclusion of Liability

Danfoss rejects all liability when the conditions of assembly and use described in this manual as well as those described by the standard EN

834: 2013 are not observed.

1.3.4 Modifications

Danfoss reserves the right, without prior notice, to make any modifications with a view to improving the product.

2. Product Description

2.1 Packaging

2.2 General Description

Contents of the SonoHCA allocator box:

Box with label describing the product

5 10-piece trays with premounted lead seal

2.2.1 Type

The electronic heat cost allocators SonoHCA operate either according to the single sensor principle with start sensor or the double sensor principle. The device has been developed and approved in accordance with the European Standard EN 83 4:2013.

2.2.2 Design

The heat cost allocator consists of a microprocessor, a lithium battery, two temperature sensors, a heat conducting aluminium back plate, a multi-functional display and a plastic housing.

1 box of 50 back plates Installation guide

The measuring circuit consists of the temperature sensors, the analogue-digital conversion, the reference resistance for standardising the measuring transformation and the microprocessor for accessing the radia-tor heat output. During each measuring the circuit tolerances are eliminated with a reference resistance and the heat cost allocator carries out an automatic self-test.

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Operating Guide SonoHCA

2.2 General Description

(continuous)

Standard aluminium back plate for nearly all existing bolts with common dimensions and mounting possibilities – thus easy installation

2.2.3 Characteristics

• Measuring by two temperature sensors, radiator and ambient temperature sensor (NTC-resistor).

• Optional measuring principle: 1 sensor mode with start sensor or two sensor mode.

• Unit scale or product scale.

• Recording of cumulated heat consumption on

the annual set day.

• Recording of 144 monthly values and 18 half monthly values for cumulated heat consumption.

• Recording of 18 monthly values for the maximum radiator temperature.

• Optical interface for the readout of the data and programming

• For heat cost allocator SonoHCA, the radio module comprises a unidirectional radio transmitter.

Two telegrams: short telegram, OMS

compliant and long telegram for Walk-by reading.User-friendly operation by push button.

• 6-digit and high-contrast LCD display.

• Automatic commissioning during the

mounting on the aluminium back plate (available when ordering).

• Check code for postcard mail-in method

• Possibility to connect a remote sensor on each

version of heat cost allocator. The remote sensor will be automatically detected by the heat cost allocator.

• Remote sensor version with 2 m cable.

• Standard aluminium back plate for nearly

all existing bolts with common dimensions and installation possibilities – thus easy installation (no cutting and welding of bolts necessary).

• Snap-on blind to cover colour shadows for increased aesthetics.

• Safe operation and fraud/manipulation detection.

• Lithium battery with a capacity of up to 10+1 year.

• Meets EN 834:2013.

Snap-on blind to cover colour shadows for increased aesthetics

2.2.4 Display

The heat cost allocator has a LCD-display with 6 large main digits on the right and 2 smaller digits on the left as well as two special symbols and one communication indicator. The main digits are separated by four decimal points. Below, please find the display segments:

Display with all active segments

Normally, the heat cost allocators are supplied with switched-off LCD-display. On request, the heat cost allocators can also be supplied with permanent LCD- display.

2.2.5 Electronics

The device has an electrical circuitry with an 8-Bit-CMOS-micro controller of the latest generation STM8L with extremely low current consumption operating at a voltage as from

1.8 V.

The temperature measuring circuit with automatic self-calibration measures the discharging time of a capacitor. The accuracy of the measuring circuit is independent of the supply voltage.

2.2.6 Versions

For each version of heat cost allocator, it is possible to plug the connector of the remote sensor to an interface inside the heat cost allocator.

Once equipped with a remote sensor, the heat cost allocator will only work for an application with remote sensor. Remote sensor version with 2 m cable.

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Operating Guide SonoHCA

2.2 General Description

(continuous)

2.3 Technical data

2.2.7 Optical Interface

With a standardised optical probe the consumption and configuration values can be transferred directly to a computer. With the radio heat cost allocator all consumption values can be readout over the optical interface and over radio. The data are transmitted in M-bus-format acc. to EN13757-3. Authorised personnel can alter the configuration of the device over the optical interface with an optical probe.

Single sensor device with start sensor

for heating systems with tmmin ≥ 55 °C Calculation with set reference temperature 20 °C

Optional measuring systems:

Optional scales: Unit scale or product scale

Current supply: 3 V-Lithium-battery

Life-span with 1 battery: > 10 years

Display: Liquid crystal display (LCD-display)

No. of displayed digits: 6 digits (000000 ... 999999)

Sensor temperature range: 0 °C ... 120 °C

Exponent: n = 1.33

Radiator – performance range: 4 Watt ... 16.000 Watt

(tm

... tm

Design temperature range:

Values: Rating fac tors see digital KC-data base

Models: Compact device or remote sensor device

Set day: Freely programmable

Data storage:

Self-test: Before every measuring

Start of counting:

Satndard version: EN 834:2013

Homologation according to: HK VO : A1.0 2. 2015

Conformity: CE

Standard mounting height:

Wireless M-Bus radio communication

Frequency: 868.95 MHz

Communication: Unidirectional

Protocol: Wireless M-Bus

Encryption: AE S-128

Transmission standard: EN 13757-4, mode T1

Broadcasting interval:

Data transmission periods:

(tm

min

... tm

Necessar y rating factors: KQ, KC, (KA, KT)

Double sensor device

for heating systems with tmmin ≥ 35 °C Calculation with variable ref. temperature T-air sensor Necessar y rating factors: KQ, KC, (KA, KT)

Single sensor device with start sensor

)

max

55 °C ... 105°C / 120 °C (compact- / remote sensor)

Double sensor system

)

max

35 °C ... 105°C / 120 °C (compact- / remote sensor)

144 monthly values and 18 half monthly values for cumulated heat consumption, 18 monthly values for the maximum radiator temperature. Maximum temperature of the current and previous year, all relevant consumption values

Heating period 25°C – 40°C (programmable) Off-heating period 25°C – 40°C (programmable)

At 75% of the overall height of the radiator. If the height of the radiator is less than (<) 470 mm, the heat cost allocator must be installed at 50% BH.

Short telegram (OMS): > 120 s Long telegram (walk-by): > 120 s

Short telegram (OMS): 24 h/d, 7 days a week Long telegram (walk-by): < 12 h/d, 7 days a week

2.2.8 Radio Wireless M-Bus

The radio heat cost allocator features a transmitter circuit in the 868 MHz band with integrated antenna.

This radio module comprises a unidirectional radio transmitter which is used to transfer data according to the wM-Bus (EN 13757-4) radio communication protocol and in compliance with the OMS (Open Metering System) Release V3.0.1.

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Operating Guide SonoHCA

2.3 Technical data

(continuous)

3. Settings

3.1 Settings

Dimension

The following table can be used to determine the configuration of the heat cost allocator by combining the different settings options that follow.

Due to distinctive technical features, not all possible combinations are necessarily achievable.

Configuration sheet for SonoHCA:

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Operating Guide SonoHCA

3.1 Settings (continuous)

• Position 1: Not used.

• Position 2: Allocator Date and Standard

Time:

The UTC time zone will be programmed

in accordance with the country where the allocator is in-stalled.

• Position 3: Set Day (yearly date): It is possible to program an annual set day on

which the cumulative consumption value to date is recorded.

• Position 4: Setting Winter / Summer Periods:

2 options: yes / no. If the ‘yes’ option is chosen, two different

specific heating periods (winter and summer) with different start temperatures settings depending on the current period can be distinguished.

• Position 5: Set the Start of the Summer Period:

Choose the date on which the summer period

will begin.

• Position 6: Set the Start of the Winter Period:

Choose the date on which the winter period

or the heating period will begin.

• Position 7: Unit Scale and Product Scale:

2 options: unit scale / product scale. Set the type of scale used when calculating

the display values.

By default, the KC and KQ evaluation factors

will be set to 1 for the product scale.

• Position 8: Set Cumulative Values to Zero:

2 options: set day / never. Determine whether the units’ consumption

totalizer will be reset to zero on the set day or never.

• Position 9: Single Sensor or Dual Sensor Mode:

Set the measuring method used by the

allocator.

2 options: single sensor / two sensors. Single sensor: determines the amount of

heat emitted by a radiator by measuring and assessing the radiator’s temperature with respect to that of the room temperature measured at the start and fixed at 20°C.

Two sensors: determines the amount of heat

emitted by a radiator based on the measured temperature of the radiator via the radiator temperature sensor and the ambient air sensor.

• Position 10: Elimination of Summer Counting:

2 options: yes / no. If the ‘yes’ option is chosen, consumption will

not be measured during the summer period.

• Position 11: Radiator Temperature TR , Start Counting Summer Period:

Set the threshold temperature for the start

(counting) of the allocator. When this start temperature is reached, the allocator will begin to count the consumption units.

• Position 12: Radiator Temperature TR , Start Counting Winter Period:

Set the threshold temperature for the start

(counting) of the allocator. When this start temperature is reached, the allocator will begin to count the consumption units.

• Position 13: Max. room temperature TA ,

Activation of Heat Accumulation Mode, Sum-mer Period:

Set a reference temperature in order to

avoid an incorrect measurement due to heat accumulation (e.g. if the radiator is hidden by panels, thermal accumulation). The allocator will automatically switch into single-sensor mode when the ambient temperature measurement surpasses the defined reference temperature. Following this, the calculation will use an ambient temperature set to 20°C rather than the temperature actually measured.

• Position 14: Max. room temperature TA ,

Activation of Heat Accumulation Mode, Winter Period:

Set a reference temperature in order to

avoid an incorrect measurement due to heat accumula-tion (e.g. if the radiator is hidden by panels, thermal accumulation). The allocator will automatically switch into single-sensor mode when the ambient temperature measurement surpasses the defined reference temperature. Following this, the calculation will use an ambient temperature set to 20°C rather than the temperature actually measured.

• Position 15: Minimum Temperature

Difference, Summer Period:

Set a reference value calculated using the

temperature difference between the radiator and the ambient air. According to the standard EN 834: TR - TA ≤ 5 K.

• Position 16: Minimum Temperature

Difference, Summer Period:

Set a reference value calculated using the

temperature difference between the radiator and the ambient air. According to the standard EN 834: TR - TA ≤ 5 K.

• Position 17: Standard Ambient

Temperature TA, Summer Period:

Ambient temperature value used to calculate

the unit’s consumption. Set by the standard EN 834: TA = 20°C.

• Position 18: Standard Ambient

Temperature TA, Winter Period:

Ambient temperature value used to calculate

the unit’s consumption. Set by the standard EN 834: TA = 20°C.

• Position 19: Measuring Cycle, Summer

Period:

Set a time interval to be used as an operations

measuring cycle. The allocator will therefore usually be in sleep mode.

• Position 20: Measuring Cycle, Winter

Period:

Set a time interval to be used as an operations

measuring cycle. The allocator will therefore usually be in sleep mode.

• Position 21: Commissioning of the

Allocator:

2 options: Automatic commissioning upon

installation on the back plate / By pressing the push button after installation on the back plate.

The allocator leaves the factory in sleep mode,

meaning that it does not measure or calculate consumption. The transition from sleep to installation mode can be carried out in 2

Operating Guide SonoHCA

different ways: automatically upon installation on the aluminium back plate or by pressing the push button after having installed it on the aluminium back plate.

• Position 22: 24-hour Active Display: 2 options: yes / no. If the ‘no’ option is chosen, the display will

always be switched off. By pressing the push button, the LCD screen will become active. After 3 minutes of inactivity, the screen will automatically re-turn to deactivated mode.

If the ‘yes’ option is chosen, the display will be

active 24 hours a day.

• Position 23: Scrolling Display Menu: 2 options: yes / no. If the ‘no’ option is chosen (static display), the

menu can be changed by pressing the push button.

If the ‘yes’ option is chosen, the display will

automatically move from one menu to the next. The display duration can be configured individually for each duration.

• Position 24: Error Information Display: If an error occurs, the Err message will appear

on the LCD screen. This information will appear at the top of the menu sequence.

• Positions 25 to 39: 15 values which can be displayed.

• Position 40: Programmable Display Time for Each Value Shown.

• Position 41: Operation Mode for the Wireless M-Bus Radio:

2 options: short telegram (OMS) / long

telegram (Walk-by).

• Position 42: Transmission Interval for

Wireless M-Bus Radio Telegram:

Set a transmission interval for sending

Wireless M-Bus radio telegrams.

• Position 43: Wireless M-Bus Radio

Telegram Transmission Period.

Short telegram (OMS): 24 hours a day, 7 days a

week.

Long telegram (walk-by): 12 hours chosen per

day (programmable), 7 days a week.

• Position 44: AES-128 Encryption Activated

at Factory:

2 options: yes / no. If the ‘yes’ option is chosen, the encryption

key can be programmed according at the customer’s request.

• Position 45: Decryption Key: Contact the local Danfoss for Decryption Key.

• Position 46: Installer Password: Default password: 56781234 This may be chosen by the customer.

• Position 47: Detachable Label Attached to

the Heat Cost Allocator:

2 options: yes / no. If the ‘yes’ option is chosen, a detachable

label will be attached to the front face of the allocator.

• Position 48: Information Contained on the

Detachable Label:

The information contained on the detachable

label may be chosen by the client.

3.2 Operating mode 3.2.1 Cycle

The heat cost allocators SonoHCA operate in a cycle of 4 minutes. Most of the time, the device is in sleeping mode. Every 4 minutes the device is set into operation and operates according to the adjoining diagram.

The clock-pulse generator is a counter which is completely independent from the rest of the program. This counter is designed in a way so that it is impossible to stall the cycle or to skip one or more cycles.

Each cycle follows the adjoining diagram. The measuring and calculating processes are explained in detail later.

The tasks carried out during one cycle are taking approx. 100 ms. This means that the device is in sleeping mode more than 99.8 % of the time. It can be set into operation between two cycles over the optical probe or by pushing the button. In this case it carries out the requested task and then returns to sleeping mode.

In case an optical probe is connected or the button is pushed during the course of the cycle, the respective value is readout at the end of the cycle.

The button can be pushed for an indefinite period of time and the optical probe can be left in its position since the normal function of the device is not impaired by an influence from outside.

Operating Guide SonoHCA

3.2 Operating mode

(continuous)

3.2.2 Single Sensor Version with Start Sensor

The start sensor of the single sensor version serves as an ambient temperature sensor which mainly functions during the heating up period.

The start temperature is the threshold temperature of the radiator at which the device always starts to carry out energy ratings. For these ratings, the measured radiator temperature and an assumed ambient temperature of 20° C are used as calculation basis.

3.2.3 Dual Sensor Version

For the dual sensor version basically the same specifications apply as for the single sensor version with start sensor. However, for calculating the room temperature the real temperature, measured by the ambient temperature sensor (corrected via the corresponding radiator-dependent „Kairvalue“), is used as the basis.

3.2.3.1 Heat Accumulation Mode

In order to avoid faulty measuring due to heat accumulation (e.g. in case the radiator is hidden by panels), the device switches from a defined ambient temperature (e.g. 28°C) to the one sensor mode and calculates with an ambient temperature of 20° C.

3.2.4 Comparison of the Measuring Principles

Single sensor device with start sensor measuring principle

For heating systems with tm

≥ 55 °C

min

The heat cost allocator calculates with a set reference temperature of 20 °C

Application: Single sensor devices with start sensor are used in areas where normal ambient temperatures are given. For low temperature heating systems the double sensor device is recommended.

For radiators which are covered or blocked by fix-tures, normally the single sensor devices are used because the double sensor device is not in a posi-tion to capture the current ambient temperature due to the heat accumulation.

double sensor system which then switches over internally to the single sensor mode.

Within one billing unit, only one measuring principle (either single sensor measuring principle with start sensor or double sensor measuring principle) can be used. Mixed fitments or the use of different types of devices in the same billing unit is therefore also not allowed.

The processes for determining the K-value for the single sensor device with start sensor and the double sensor device are identical. It is only the measuring principle that is different.

3.2.5 Temperature Measurement and Calculation

The temperature is measured with an NTC – resistor. For the resistance measurement the discharging time of the capacitor is measured. The measurement is carried out as follows:

3.2.5.1 Measuring of a Resistor, Principle

1. Charging of the capacitor

2. Discharging of the capacitor through the

resistance which is to be measured. At the same time a 16+1 bit-timer starts with the discharge to measure the discharging time

3. As soon as the voltage on the capacitor

terminals reaches a certain value, an interrupt is induced and the timer stops. At the same time the discharging of the capacitor is stopped as well.

After the three mentioned stages, the timer provides a 16-bit-value which corresponds to the discharging time of the capacitor through the resistance which is to be measured. In case the resistance is known (reference resistance), the constant ratio between discharging time and resistance can be assessed.

3.2.5.2 Calculation of the Value of an Unknown Resistance (e.g. sensor resistance)

The capacitor C is loaded at constant current. The interrupt at the end of the discharge is triggered by the same threshold voltage (a fraction of the discharge voltage). If these two conditions are met, the discharge time is directly proportional to the resistance. With a reference resistance R whose exact value is known, it is now possible to

ref

calculate the unknown resistance value Rx with the following equation:

Double sensor measuring principle

For heating systems with tm

≥ 35 °C

min

The heat cost allocator calculates with a variable reference temperature T

air temperature

Application: Double sensor devices are used in areas where precise measuring of the ambient temperature is necessary and/or in low temperature heating systems.

Radiators which are covered or blocked by fix-tures are detected automatically by the

From this equation the self-calibration of the converter can be derived, which is given by measuring the discharging time through the reference resistance.

3.2.5.3 Measuring of the Radiator and Ambient Temperature

The following measurements are carried out during one cycle:

1. Measuring of the reference resistance Rref

2. Measuring of the ambient temperature sensor

NTC

Operating Guide SonoHCA

3.2 Operating mode

(continuous)

3. Measuring of the radiator temperature sensor NTC

The measuring values are calculated with the following formula:

The reference resistance value is defined ex works with a tolerance of 0.5% with 50 ppm. The reference resistance features an excellent temperature and long-term stability.

The capacitor value and the threshold voltage have to remain stable over the whole cycle. However, they can vary at the medium- or long term without causing any failures because the self-calibration of the converter is repeated in every cycle while measuring the reference resistance.

3.2.6 Calculation of the Displayed

Consumption Value

The value displayed on the heat cost allocator is calculated as follows:

Single sensor device

Double sensor device

3.2.7 Start of Counting

The updating (increment) of the consumption value is carried out under the following conditions:

During winter period (heating period):

(TR ≥ 25 °C)

(TR ≥ 20 °C) AND (TR - TA ≥ ΔT

MIN

)

During summer period (off heating period):

(TR ≥ 35 °C)

(TR ≥ 20 °C) AND (TR - TA ≥ ΔT

MIN

)

Explanation:

TR Radiator temperature TA Ambient temperature ΔT

Minimum temperature difference between

MIN

radiator and room

3K for standard device (winter heating

period standard setting)

4K for remote sensor device (summer

heating period standard setting)

Note:

The thresholds of starting (25°C et 35°C) are indicative values. These temperatures of starting are adjusted according to the needs and specif icities of the customer.

Explanation:

TH Temperature of the radiator surface in [°C] TA Ambient temperature in [°C] Q Displayed consumption value, without

unit

Kc Factor that carries back the ΔT measured at

a normalized value

Kq Factor Kq is a numerical value of the

nominal power of the radiator stated in [KW]

Unit scale:

Kc = 1 and Kq = 1

Product scale:

Kc <> 1 and Kq <> 1

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Danfoss Heat Cost Allocator Operating guide

Specifications and Main Features

Frequently Asked Questions

User Manual