Indoor Air QualityController IAQH-C
This device is especially designed for the automatic windows of the VELUX
company.
User Manual
April , 2018
FRAKTA Vertriebs GmbH
Riedwiese 13/1
D-72229 Rohrdorf
Phone: 0049 (0)7452 605 1991
Mail: verkauf@frakta.de www.frakta.de Specification subject to change without notice
Made in Germany , Printed in Germany
User Manual – Indoor Air Quality Controller
IAQH-C
Page 2
1 Intended Use ........................................................................................................................................3
2 Functional Description .......................................................................................................................3
2.1 VOC Sensor ................................................................................................................................3
2.2 Air Quality Measurements ...........................................................................................................3
2.3 Temperature Measurement .........................................................................................................4
2.4 Functions .....................................................................................................................................5
2.4.1 Air Quality Sensor ....................................................................................................................5
2.4.2 Humidity Sensor .......................................................................................................................5
2.4.3 Function Temperature Limitation .............................................................................................5
2.4.4 Function Window Control .........................................................................................................5
3 Installation............................................................................................................................................6
4 Electrical Connection ..........................................................................................................................6
5 Commissioning ...................................................................................................................................6
6 Troubleshooting ..................................................................................................................................6
7 Figures ..................................................................................................................................................7
8 Specifications ......................................................................................................................................8
9 ModBus ................................................................................................................................................9
9.1 General ........................................................................................................................................9
9.2 Physical Port ................................................................................................................................9
9.3 Time Response ...........................................................................................................................9
9.4 ModBus Functional Description .................................................................................................10
9.5 Troubleshooting .........................................................................................................................11
9.6 ModBus Read Register Description ..........................................................................................12
9.7 ModBus Write Register Description ..........................................................................................13
10 Notes and General Information ........................................................................................................14
10.1 Installers’ Responsibilities ......................................................................................................14
10.2 Maintenance ..........................................................................................................................14
10.3 Limited Warranty ....................................................................................................................14
11 Part Disposal ......................................................................................................................................14
User Manual – Indoor Air Quality Controller
IAQH-C
Page 3
Metal Oxide IAQ Indoor Air Quality (VOC) Transmitter
1 Intended Use
The indoor air quality control IAQH-C with digital processing of the measuring values and temperature
compensation is used for measuring and controlling the air quality in indoor areas within environmental
conditions specified in the Technical Data.
The intended sites are all areas being directly connected to the public low voltage supply, e.g. residential,
commercial and industrial ranges as well as small enterprises (according to EN50 082).
The indoor air quality control IAQH-C must not be used in potentially explosive atmospheres.
2 Functional Description
2.1 VOC Sensor
The semi-conducting metal oxide sensor measures the electrical conductivity of the nanocrystalline metal oxide
coated on a heatable substrate. The typical operating temperature is between 300 and 400 °C. The doping of
the metal oxide with noble metals results in a positive sensibility to combustible gases like VOCs, carbon
monoxide and natural gas. The doping permits the adaptation to the demands of the measuring task. VOCs are
partially or totally burnt at the sensor surface by the oxygen of the metal oxide. The electrons released in the
semi-conductor by this process lead to an increase of the electrical conductivity. At the end of the combustion
process, the metal oxide returns to its initial state by incorporating oxygen from the air, with the conductivity
also adopting the initial value. The change of the conductivity is evaluated via the internal micro-controller and
output as a standard signal.
2.2 Air Quality Measurements
The VOC content in indoor areas is mainly determined by the persons present and their activities. See table 1.
When for example working with cleaning agents or when cooking, VOCs (Volatile Organic Compounds) are set
free, but also human respiration is a constant source of volatile metabolism products (VOCs). The air quality
sensor detects the increasing VOC level and calculates the proportional CO2 value. The VOC/CO2 correlation
was determined by taking measurements under real conditions. See diagram 1.
To this day, there aren’t any standard signals for the VOCs; therefore the IAQ air quality sensor reduces the
measured VOC values to CO2 equivalents with the unit ppm. This grants the compatibility to existing CO2
ventilation standards.
Each time the IAQ air quality transmitter is switched on, it runs through a warm-up period of 20 minutes. During
this warm-up period there aren’t any measurements; the sensor outputs the signal of 80% of the measuring
range.
After the warm-up period, the sensor interprets the currently read VOC value as zero-point, independently from
the actual concentration. An internal algorithm continuously updates the zero-point by taking the lowest
measured VOC value. Therefore the ambient air should be of low VOC content after the warm-up period. This
can be obtained by shortly venting when starting the measurements with the 80% signal.
If the sensor isn’t started at low VOC concentrations, it can take a couple of days until the internal algorithm
has updated the zero-point so far that effective measuring results are available.
The natural sensor drift and ageing is corrected by the implemented control algorithms.
User Manual – Indoor Air Quality Controller
IAQH-C
Page 4
Indoor Air
Typical Substances
Ventilation
Contamination
Source
Emission Source
VOCs
Others
demand
controlled
Human Being
*Breath
Acetone, Ethanol, Isoprene
CO2
Humidity
*Skin respiration &
transpiration
Nonanal, Decanal, α-Pinene
Humidity
*Flatus
Methane, Hydrogen
*Cosmetics
Limonene, Eucalyptol
*Household Supplies
Alcohols, Esters, Limonene
*Combustion
(Engines,
Appliances, Tobacco
Smoke)
Unburnt Hydrocarbons
CO
CO2
Humidity
*Building Material
*Furniture
*Office Equipment
+Consumer Products
*Paints
*Adhesives
*Solvents
*Carpets
Formaldehyde, Alkanes,
Alcohols, Aldehydes,
Ketones, Siloxanes
permanent
(5-10%)
*PVC
Toluene, Xylene, Decane
*Printers/Copiers,
Computers
Benzene, Styrene, Phenole
Table 1 – Typical indoor air contaminants (VOC and others)
Diagram 1: Correlation CO2- VOC (records from a business meeting session)
2.3 Temperature Measurement
The temperature measurement is done via an internal sensor. The signal is used as protection against the
cooling down of the room and isn’t output.
Additional heat sources in the flash-mounted box have an influence on the temperature
measurements and have therefore to be avoided.
0
1hr
2h
3h
4h
CO2 VOCs
VOCs
CO
2
Odors
Window
opened/closed
User Manual – Indoor Air Quality Controller
IAQH-C
Page 5
2.4 Functions
2.4.1 Air Quality Sensor
The air quality sensor measures the VOC concentration and converts it into the CO2 equivalence. This signal is
only used internally and is not output.
2.4.2 Humidity Sensor
The integrated humidity sensor measures the current humidity in the room in order to reduce the humidity by
opening the window in case of too high humidity. This signal is only used internally and is not output.
2.4.3 Function Temperature Limitation
The fixed temperature of 16°C prevents the room from being cooled down too extensively. If the indoor
temperature falls below this value, the window(s) is/are closed.
2.4.4 Function Window Control
The automatic operation of the window control is only active, if the function switch at the control panel is in
AUTO position. In this mode the LED is lit in green.
In OFF position the LED is red. (The functionality of the device is turned off.)
If either the thresholds of the air quality or those of the humidity are exceeded, the controller opens the
associated windows.
At good air quality and/or low indoor humidity, the windows stay closed in switch position AUTO.
At poor air quality and/or exceeded indoor humidity, the windows are opened.
During the opening/closing of the automatic windows, there is no possibility to change the direction. W hen the
final position is reached, the inversion of the direction is performed with delay.
For energy-optimized ventilation the window is only opened for max. 6 minutes, and the automatic windows
then stay closed for at least 30 minutes. The sequence is repeated if the thresholds set by the adjusting wheel
are still or again exceeded.
Function block diagram
The control parameters are factory-set, an adaptation to the application, however, is possible via MODBus.
User Manual – Indoor Air Quality Controller
IAQH-C
Page 6
3 Installation
Mounting Instructions
When choosing the mounting site please pay attention to the following:
Do not mount the transmitter next to doors, windows, air inlets and outlets.
Free air supply must be granted.
Vertical mounting (air inlet at the transmitter down/up)
Avoid direct sunlight.
No heat sources around in case of temperature measurement.
Fig. 3: Mounting VOC Transmitter
4 Electrical Connection
The connection is done via screw-type terminals with a section of 0.25 to 1.5 mm2.
The connection of the different applications is shown in the figures 7 to 11.
For ModBus wiring we recommend using the cable Y(St)Y 2x2x0.8 LG, in line topology and without
any branch lines. Please consider in addition all regulations concerning the wiring of RS-485 field bus
wiring.
5 Commissioning
Check for correct mounting location.
Check power voltage at the terminals 1 (+) and 2 (GND) at X2.
Check the output terminals to the VELUX radio switch terminals X4 1,2,3
Check power supply
Rack in of the power supply
Switch on position AUTO LED is lit in green
Turning the knob to the right (line upwards) For opening the window
Turning the knob to the left (line downwards) For closing the window
6 Troubleshooting
If the LED at the device is flashing in turn red and green – there is an internal error and the device is
out of order. Please call your contact person.
78,3mm
83,4mm
60mm
60mm
= 3mm
User Manual – Indoor Air Quality Controller
IAQH-C
Page 7
7 Figures
Version 230 V power supply Version 24V power supply
Fig. 10: Electrical connection 230V version
Fig. 12: Terminal positions of the PCB
Operating Switch
Power Supply
Switch Output to
Velux Radio Actuator
Operating Mode LED
User Manual – Indoor Air Quality Controller
IAQH-C
Page 8
8 Specifications
Electrical
Supply voltage 24 V version
230 V version
24 VAC ±10%, 50 Hz /VDC±20%
230 VAC ±20%, 50 Hz
Power consumption
Approx. 30 mA + power of the digital outputs
VOC sensor data
Gas type
VOC (alcohols, aldehydes, aliphatic
hydrocarbons, amines, aromatic hydrocarbons,
carbon monoxides, methane, LPG, ketones
and organic acids)
Sensor element
Metal oxide semi-conductor
Measuring range
450 – 2,000 ppm CO2 equivalency
Accuracy
± 150 ppm
Repeatability
± 5 % of reading
Response time
t90 60 s
Warm-up time
20 min
Expected life time
> 10 years/ normal ambient conditions
Temperature sensor data
Sensor element
NTC
Measuring range
0 – 50 °C (32 to 122 °F)
Accuracy
1 % of reading
Humidity- sensor data
Sensor element
SMD Polymer
Measuring range
0 – 100% RH
Accuracy
± 3 % of reading
Expected life time
> 10 years/ normal ambient conditions
Output signal
Digital output signals
Option: max. 60V AC / DC 20 mA
Ambient conditions
Humidity
15 – 90 % RH non condensing
Temperature
0 °C to + 50 °C (32 to 122 °F)
Temperature storage
5 °C to + 50 °C (41 to 122 °F)
Pressure range
Atmosphere ± 10 %
Physical
Housing
Plastic ABS
Colour
Pure white similar to RAL 9010
Weight
Approx. 95g (0.21 lb.)
Wire connection
Screw-type terminal min. 0.25, max. 1.5 mm2
Directives
EMC Directives 2004/108/EEC
EN 61000-6-2, EN 61000-6-3
72/23/EEC: EN 60730
Electrical
Elektrisch
Versorgungsspannung
24 VAC/VDC±20%, 50 Hz
Leistungsaufnahme
ca. 30 mA zuzüglich Leistung der digitalen
Ausgänge
VOC- Sensordaten
Gasart
* VOC (Alkohole, Aldehyde, aliphatische
Kohlenwasserstoffe, Amine, aromatische
Kohlenwasserstoffe, Kohlenmonoxide,
Methan, LPG, Ketone und organische Säuren)
Sensorelement
Metall Oxid Halbleiter
User Manual – Indoor Air Quality Controller
IAQH-C
Page 9
9 ModBus
9.1 General
The ModBus protocol was developed for the data exchange between information processing units,
programmable logic controllers and other intelligent systems. A master computer communicates with maximum
247 connected devices via a serial data link of RS-485 standard. There is only one device (host, master) per
bus line determining the telegramming. The other devices (clients, slaves) only react on the request of the
master and are never allowed to send data on the bus line without request of the master device.
The data are transmitted in form of data telegrams. There are two possible formats within the ModBus protocol,
the ASCII and the RTU format. Only the RTU format is used and described in here.
The RTU telegram settings don’t include any tag delimiters.
The beginning and the end of data telegrams are realized by short stops.
The syntax is as follows:
Address Command Data CRC16
The data are transmitted with binary code. The address and the command are 1 byte each. When requested
from the master, the data may contain for example address, order and the initial address and the number of
data to be retrieved.
The answer from the slave is structured in the same way. The data may contain, besides the address and the
order, for example the number of sent data bytes and the data.
CRC16 is a 2-bytes Cyclical Redundancy Check.
The end of the data telegram is recognized if there is an idle period of minimum 2 characters.
The slaves react to valid requests after a certain timeout after receipt of the last character by giving the
corresponding answer. The master then expects the start of the answer. If it doesn’t come, the master can
occupy the bus anew and give new commands. The slave answers after a silence of 3.5 characters at the
earliest. In case of transmission errors or not executable commands, the slave doesn’t answer or responds with
an error message (see troubleshooting).
9.2 Physical Port
The communication between master and slaves uses a serial data link of RS-485 standard.
The port settings are as follows:
9600 Baud, 1 Start Bit, 8 Data Bits, Parity none, 1 Stop Bit
9.3 Time Response
Transmission telegram:
The master can start a data exchange. The master sends a data telegram to a slave containing:
Address of the slave
Function requested from the slave (order)
Data field (variable depending on the order)
Control characters
The slave starts uploading a telegram after each idle period of 3.5 characters. If the first character is the slave’s
own address or the address 0 (all), it processes with the telegram. If there is a silence of 2 characters at least,
it considers the telegram finished and checks the CRC.
If the telegram is without errors, it executes the function and composes an answer.
User Manual – Indoor Air Quality Controller
IAQH-C
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Answer telegram:
Address of the slaves
Executed function (order)
Data field (e.g. data length and data)
Control characters
The answer is sent at the earliest after a silence of 3.5 characters after the end of the master’s telegram.
In case of an error, the slave waits for the end of the telegram and the period of 3.5 characters, and then
returns an error message.
The master awaits the answer of the slave or a timeout (see table) before starting a new exchange in order to
avoid complications resulting from mutual transmissions.
Data organization
The devices offer properties and states generally described here as objects. These objects can be asked
specifically as bit or byte ranges by the master and changed by it.
An input object can only be read.
An output object can be read or written.
ModBus functions
The following functions are available with the communication protocol ModBus:
The main functions granting the data exchange.
The additional functions for the control and the diagnosis of the data exchange.
The table below indicates the functions managed here.
The functions “Read” and “Write” refer respectively to the action of the master.
Function
Description
Implemented
03
Reading of N output registers
Yes (max 32 reg.)
16
Writing of N output registers
Yes (max 22 reg.)
9.4 ModBus Functional Description
Function 03: Reading of N output registers
This function enables to read the output registers; these are the registers the master can read or write in the
slave.
This function enables to read the input registers; these are the registers the master only can read.
Example:
Reading of N registers; function 3
Request:
Slave address
1 - 254
Function
03
Start address
Number of words
CRC16
1 Byte
1 Byte
2 Bytes
2 Bytes
2 Bytes
Answer:
Slave address
1 – 254
Function
03 or 04
Number of sent bytes
Data
CRC16
1 Byte
1 Byte
1 Byte
n Bytes
2 Bytes
User Manual – Indoor Air Quality Controller
IAQH-C
Page 11
9.5 Troubleshooting
If there is any parity, framing, overrun or CRC error during receipt of a telegram, the slave doesn’t accept and
answer it.
If the slave cannot execute the requested order, it sends an error message.
Format of an error message:
Slave address
1 - 254
Answer code
Error code
CRC16
1 Byte
1 Byte
1 Byte
2 Bytes
Answer code: Order function code + 0x80 (the most significant bit is set to 1).
User Manual – Indoor Air Quality Controller
IAQH-C
Page 12
9.6 ModBus Read Register Description
Read register Request with command 0x03
Register
Description
Range
Default
0
Sensor type
(defined by product type)
19505
1
Measured value: Air quality
0- max (defined in register 11) in ppm
2
Measured value: Temperature
0- max (defined in register 12) in °C
3
PID output value VOC
0-10000
4
PID output value Temp
-10000 to +10000
5
Measured value: Humidity
0-100% RH
6
Hysteresis for humidity
Fixed: 10% of the set threshold
7
Threshold for air quality
Potentiometer value current setting in ppm
8
Threshold for humidity
Potentiom. value current setting in % RH
9
Internal
10
Own MODBus address
1-255
245
11
Measuring range air quality
0-32767
4000
12
Measuring range temp.
0-32767 (50 with 1 decimal place)
500
13-17
Internal
18
Min. temp. limit cooling protection
0- max (defined in register 12) in °C
16
19
Ao1 switch
0-6 1 20
Ao1_Do2 switch
fixed
101
21
Do1 switch
fixed
101
22-27
Internal
28
LED1 switch
0-28
25
29
LED2 switch
0-28
28
30
Internal
31
Initial value air quality
fixed
0
32
Initial value temperature
fixed
0
33
Switch potentiometer function
fixed
1
34
Initial value for analog output 1
fixed
0
35
Final value for analog output 1
fixed
4000
36
Output initial value for analog
output 1
fixed
0
37
Output final value for analog
output 1
fixed
4000
38
Initial value for analog output 2
fixed – not used
0
39
Final value for analog output 2
fixed – not used
500
40
Output initial value for analog
output 2
fixed – not used
0
41
Output final value for analog
output 2
fixed – not used
500
42-44
internal
45
Min. potentiom. value air quality
0- max (defined in Register 11) in ppm
900
46
Max. potentiom. value air quality
0- max (defined in Register 11) in ppm
1600
47
Min. potentiom. value humidity
0- 100 in % RH
55
48
Max. potentiom. value humidity
0- 100 in % RH
75
49
Ventilation time- complete
opening
0-32767 in minutes
6
50
Closed window time after
complete opening
0-32767 in minutes
30
51
Internal
User Manual – Indoor Air Quality Controller
IAQH-C
Page 13
9.7 ModBus Write Register Description
Write register Command with command 0x10 (16d)
Register
Function
Possible Range
Default
Note
0
Own MODBus address
1-255
254 1 Measuring range air quality
0-32767
4000
2
Measuring range Temp.
0-32767 (50 with 1 decimal place)
500
3-7
Internal
8
Min. temperature limit
0- max (defined in register 12) in °C
16 9 Ao1 switch
0-6 1 10
Ao1_Do2 switch
fixed
101
11
Do1 switch
fixed
101
12-17
Internal
18
LED1 switch
0-28
25
19
LED2 switch
0-28
28
20
Internal
21
Initial value air quality
fixed
0
22
Initial value temperature
fixed
0
23
Switch potentiometer function
fixed
1
24
Initial value for analog output 1
fixed
0
25
Final value for analog output 1
fixed
4000
26
Output initial value for analog
output 1
fixed
0
27
Output final value for analog
output 1
fixed
4000
28
Initial value for analog output 2
fixed – not used
0
29
Final value for analog output 2
fixed – not used
500
30
Output initial value for analog
output 2
fixed – not used
0
31
Output final value for analog
output 2
fixed – not used
500
32-34
Internal
35
Min. potentiom. value air quality
0- max (defined in register 11) in
ppm
900
36
Max. potentiom. value air quality
0- max (defined in register 11) in
ppm
1600
37
Min. potentiom. value humidity
0- 100 in % RH.
55
38
Max. potentiom. value humidity
0- 100 in % RH
75
39
Ventilation time- complete opening
0-32767 in minutes
6
40
Closed window time after
complete opening
0-32767 in minutes
30
41
Internal
User Manual – Indoor Air Quality Controller
IAQH-C
Page 14
10 Notes and General Information
It is important to read this user manual thoroughly and clearly in order to understand the information and
instructions. The IAQ transmitter must be used within product specification capabilities. The appropriate
operating and maintenance instructions and recommendations must be followed.
Due to on-going product development, the manufacturer reserves the right to change specifications without
notice. The information contained herein is based upon data considered to be accurate. However, no
guarantee is expressed or implied regarding the accuracy of this data.
10.1 Installers’ Responsibilities
It is the installer’s responsibility to ensure that the IAQ transmitter is installed in compliance with all national
and local codes and OSHA requirements. Installation should be implemented only by technicians familiar with
proper installation techniques and with codes, standards and proper safety procedures for control installations
and the latest edition of the National Electrical Code (ANSI/NFPA70). It is also essential to follow strictly all
instructions as provided in the user manual.
Attention:
- The electrical connections of the device have to be made according to the legal
requirements.
- To avoid personal injuries and/or equipment or other property damages, please take
care to always disconnect power supply before working on the electrical wiring.
- For avoiding property damages, the device must only be employed within the
- intended use.
Attention:
The circuits used in the device react to electrostatic discharge.
Please take appropriate precautions!
10.2 Maintenance
It is recommended to check the IAQ transmitter regularly. Due to regular maintenance any performance
deviations may easily be corrected. Re-calibration and part replacement in the field may be implemented by a
qualified technician and with the appropriate tools. Alternatively, the IAQ transmitter may be returned for
service to the manufacturer.
10.3 Limited Warranty
The manufacturer warrants the IAQ transmitter for a period of one (1) year from the date of shipment against
defects in material or workmanship. Should any evidence of defects in material or workmanship occur during
the warranty period, the manufacturer will repair or replace the product at their own discretion, without charge.
This warranty does not apply to units that have been altered, had attempted repair, or been subject to abuse,
accidental or otherwise. The warranty also does not apply to units in which the sensor element has been
overexposed or gas poisoned. The above warranty is in lieu of all other express warranties, obligations or
liabilities.
This warranty applies only to the IAQ transmitter. The manufacturer shall not be liable for any incidental or
consequential damages arising out of or related to the use of the IAQ transmitters.
11 Part Disposal
Since August 2005 there are EC-wide regulations defined in the EC Directive 2002/96/EC and in national
codes concerning the disposal of waste electrical and electronic equipment and also regarding this device.
For private households there are special collecting and recycling possibilities. For this device isn’t registered for
the use in private households, it mustn’t be disposed this way. You can send it back to your national sales
organisation for disposal. If there are any questions concerning disposal please contact your national sales
organisation.
Outside the EC, you have to consider the corresponding directives.
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