HK INSTRUMENTS RS-485 AVT Air Velocity Transmitter

Specifications

• Product Name: AVT Air Velocity Transmitter
• Published Date: 12.11.2024
• Intended Use: Air velocity and temperature measurement in ventilation ducts
• Output Signal Modes: Voltage (Vdc) and Current (mA)
• Communication Options: Modbus for -MOD models

Product Description
The AVT air velocity transmitter is designed to measure air velocity and temperature in ventilation ducts. It offers various output signal modes and communication options to suit different needs.

• Safety Precautions
  Ensure proper installation and wiring to prevent accidents or damage to the product. Refer to the user manual for detailed safety instructions.
• Commissioning
• Mounting the Product
  Securely mount the transmitter in the ventilation duct according to the provided guidelines to ensure accurate measurements.
• Wiring
  Follow the wiring instructions carefully to connect the transmitter correctly to the power source and any control systems.
• Maintenance
  Regularly clean the probe and sensor element of the transmitter to maintain accurate readings. Refer to the user manual for detailed cleaning instructions.
• Modbus Communication
  If using Modbus communication, configure the input and holding registers as needed for seamless integration with your system.
• Disposal
  Follow local regulations for proper disposal of the transmitter at the end of its lifecycle to minimize environmental impact.
• Warranty Policy
  Refer to the warranty policy provided by HK Instruments for information on coverage and terms.

INTRODUCTION

Thank you for choosing an AVT air velocity transmitter. It is an air velocity and temperature transmitter for ventilation ducts. The AVT air velocity transmitter is available with several options:

• The -D models have a PID controller for air velocity and a display that shows air velocity and temperature measurement values.
• The -MOD models have an RS-485 connection for Modbus RTU communication.
• The -R model includes a relay and a relay connector.

The -MOD models have Modbus communication instead of analog outputs. Other models have one analog air velocity output and one analog temperature output. You can select the output signal mode and measurement range for the analog outputs during commissioning. The available output signal modes are voltage (Vdc) and current (mA). Devices without the -D option have three field-selectable measurement ranges for air velocity. The measurement unit is m/s. You can select the air velocity measurement range with jumpers. The measurement unit for temperature is Celsius. The -D models provide a freely selectable measurement range for air velocity. The available measurement units are m/s and ft/min. You can select the measurement range via the device menu (-D models). The available measurement units for temperature are Celsius and Fahrenheit.

You can configure the device settings using:

• The device menu (-D models)
• Modbus communication (-MOD models)

ABOUT THIS USER GUIDE

• This user guide contains important information about the installation, wiring, configuration, and use of the product.
• Read this guide carefully before you install the product, connect the wires, or operate the product. Make sure that you fully understand all instructions before you start work. If you are not sure what the instructions mean, contact the seller or the manufacturer.
• Follow all instructions in this user guide carefully. Always obey the applicable local rules and regulations.
• The original instructions were written in English. If there are differences between the English instructions and the translations, refer to the English instructions.
• If you find a mistake in the English instructions or the translations, please send the details to the manufacturer.

INTENDED USE

• The AVT air velocity transmitters are intended to be used in commercial environments for measuring air velocity and temperature in ventilation ducts. They are compatible with dry air. The AVT air velocity transmitters are not intended to be used with flammable or corrosive gases.
• These transmitters are intended to be connected to building automation systems in the HVAC/R industry.

SAFETY PRECAUTIONS

• The product is developed, manufactured, and tested according to high-quality standards. However, instructions for safe use must be followed when installing, using, or disposing of the product or parts of the product.
• Read this user guide carefully before you commission, use, or service this device. To avoid any kind of damage to people or property, follow the instructions carefully. HK Instruments is not liable for any hazards, injury to people, or property damage caused by incorrect installation or misuse of the device.
• To avoid electrical shock or damage to equipment, disconnect power before you install or service the product. Use only proper wiring that is rated for the full operating voltage and maximum current in the system. The wiring must also withstand fault conditions.
• To avoid fire and/or explosion, do not use the product in a potentially flammable or explosive atmosphere.
• Make sure that the product is not damaged before installation. Do not drop the product or use excessive force during installation. Do not use the product if you can see any damage.
• After installation, the product will be part of a system whose specifications and performance characteristics are not designed or controlled by HK Instruments. Refer to national and local authorities to ensure that the installation is functional and safe.
• The product should only be used in professionally designed applications. Unauthorized modifications are not allowed. The product must not be usedabouto any equipment that in case of a failure may threaten, directly or indirectly, human health or life or result in danger to human beings, animals, or property.
• In this document, there are different warnings and notes. The warning and note types are defined in the following table.

Sign	Description
WARNING:	The warning symbol indicates a potentially hazardous situation that if not avoided, could result in death or serious injury.
CAUTION:	The caution symbol indicates a potentially hazardous situation that, if not avoided, could result in minor or moderate injury.
Important:	The important symbol indicates a potentially hazardous situation that, if not avoided, could result in damage to the device or property.
Note:	The note symbol indicates a useful TIP or a recommended way to complete a task. These notes also provide information that is useful but not critical to the user.

Description of the product

This section introduces the main parts of the product and contains the technical specifications.

Main components

1	Display (-D models)	2	Cover
3	Cable gland	4	Strain relief
5	Cover locking screw (-R models)	6	Duct flange
7	Probe	8	Sensor element
9	Probe locking screw	10	Housing
11	Holes for fixing screws

12	Menu buttons (-D models)	13	Jumper for temperature output signal selection (excluding -MOD models)
14	Jumper for air velocity output signal selection (excluding -MOD models)	15	Terminal block
16	Relay (-R models)	17	Measurement range selection jumpers (excluding -D models)
18	Modbus termination jumper (-MOD models)	19	Relay connector (-R models)

Technical specifications

Property	Specification
Supply	24 Vac/dc ± 10%
Current Consumption	Max. 80 mA + 40 mA with mA output + 10 mA with relay option (DC supply voltage)
Relay (-R Models)	250 Vac, 6 A res., adjustable operating direction, switching point, and hysteresis
Air Velocity Measurement
Range	0…2 m/s, *0…10 m/s, 0…20 m/s, **freely selectable
	**200…4000 ft/min
Accuracy (typ. at 25 °C)	v ≥ 0.15 m/s and ≤ 2 m/s (0.2 m/s + 2% from reading)
	v > 2 m/s and ≤ 10 m/s (0.5 m/s + 3% from reading)
	v > 10 m/s (1.0 m/s + 3% from reading)
Response Time	T63: 1.5 s (typical, 63% of the change)
Measurement Units	*m/s, **ft/min
Temperature Measurement
Range	*0…50 °C, **-25…50 °C, **-13…122 °F (probe)
Accuracy (25 °C)	≤ 0.5 °C (air velocity > 0.5 m/s)
Measurement Unit	*Celsius, **Fahrenheit
Warm-Up Time	15 seconds
Outputs
Output Signal 1 (T out [°C])	0…10 Vdc, load > 1 kΩ
	4…20 mA, load 20…400 Ω
Output Signal 2 (v out [m/s])	0…10 Vdc, load > 1 kΩ
	4…20 mA, load 20…400 Ω
Accuracy	Vout: ± 0.025 V at 25 °C
	Iout: typically ± 0.04 mA at 25 °C, max. ± 0.1 mA at 25 °C (load 20…400 Ω)
Relay Output (-R Models)	3-screw terminal block (NC, COM, NO), potential-free SPDT
	30 Vdc, 6 A / 230 Vac, 6 A res. (IEC 60664-1 OVC II)
Modbus Communication (-MOD Models)
Protocol	Modbus RTU
Interface	RS-485
Bus Speed	9600 / *19200 / 38400 bit/s
Parity	*None / Odd / Even
Stop Bits	1 / 2

Property	Value
Display (-D Models)	2-line display (12 characters/line), 46.0 x 14.5 mm
	Line 1: velocity / Line 2: temperature (default)
	Line 1: direction of control output (optional)
	Line 2: relay status (optional)
Wiring Terminals
Type	Tilted screw terminals
Wire Size	0.2…1.5 mm² (24…16 AWG)
Tightening Torque	0.4 Nm
Commissioning Tool	Dongle with MyTool® application (available on Google Play)
Appliance Class	IEC 60664-1
Operating Conditions
Ambient Temperature	-25…50 °C (probe), 0…50 °C (transmitter housing)
Ambient Humidity	0…95% RH (non-condensing)
Storage Conditions
Temperature	-20…70 °C
Housing
Protection Class	IP54 (cables downwards) / -R and -MOD models: IP54 (cables in both cable glands)
Cable Gland	M16 (2 x M16 for -R and -MOD models)
Materials	ABS plastic, PC plastic (cover)
Probe
Dimensions	10 x 112/212/412 mm
Materials	Stainless steel (AISI 304) (probe), LLPDP (duct flange)
Mounting	With a duct flange, probe immersion length is adjustable
	50…95 mm (-100 models)
	50…195 mm (standard models)
	50…395 mm (-400 models)
Dimensions (W x H x D)	86 x 93 x 163 mm (-100 models)
	86 x 93 x 263 mm (standard models)
	86 x 93 x 463 mm (-400 models)
Weight	220 g
Warranty	5 years
Company Certificates
Quality Management	ISO 9001
Environmental Management	ISO 14001
Conformance	CE, UKCA
EMC	2014/30/EU, S.I. 2016 No. 1091
RoHS	2011/65/EU + (EU) 2015/863, S.I. 2012 No. 3032
WEEE	2012/19/EU, S.I. 2013 No. 3113
LVD	2014/35/EU, S.I. 2016 No. 1101

Dimensions

All dimensions are in millimeters (mm).

Duct flange dimensions

Commissioning

Setting the jumpers
Note: Set the jumpers in the correct position before you connect the supply voltage to the device.

Selecting the measurement range
There are different methods for selecting the measurement range. The method used depends on the device options:

• Devices that do not have a display: Select the measurement range by installing jumpers as shown in the table below.
• Models with display (-D): Select the output signal mode with jumpers and then the measurement range via the device menu. See section Selecting the output mode on page 9

Selecting the measurement range with jumpers
Install the jumpers according to the table below to select the measurement range for devices that do not have a display.

Selecting the output mode

• Select the output signal mode for -MOD models via Modbus communication.
• Models with analog outputs have two jumpers for output signal mode selection on the circuit board. Select the voltage (0…10 V) or the current (4…20 mA) output signal mode based on the system requirements. The current output is not scalable. The voltage output is scalable.
• You can configure the output signal separately for air velocity and temperature. Set the jumpers in the correct position to select the output signal mode (V/mA) for air velocity and temperature.
  See the table below for the jumper settings.

Terminating Modbus (-MOD models)
Insert the termination jumper in the last device of the network to terminate the Modbus network.

1. Disconnect the device supply voltage.
2. Open the cover.
3. Insert the termination jumper in position.
   1. Termination jumper
4. Close the cover.

Mounting the product

• WARNING: Handle the product with care. Dropping the product may cause internal damage and unwanted functions in the connected system.
• CAUTION: Place the product outside the reach of children and animals.
• Important: The product may only be installed in a location where the ambient conditions meet the operating condition requirements.
• Note: Remove the device from the ventilation duct before cleaning the duct.

Operating conditions

• Temperature -25…50 °C (probe) 0…50 °C (transmitter housing)
• Humidity 0…95 %rH (non-condensing)

1. Check that the product is not damaged during transportation.
2. Select the mounting position on a straight duct.
   Measure the length of the straight duct to make sure that the probe is positioned correctly. See the figure below for the required minimum length of straight duct.
   • Round ducts:
     • D = duct diameter
   • Rectangular ducts:
     • If there is a horizontal curve or a change in the duct size: D = width of the duct
     • If there is a vertical curve or a change in the duct size: D = height of the duct
3. Use the duct flange as a template and mark the screw holes and the probe hole on the duct.
4. Drill the screw holes and the probe hole on the duct. The maximum screw diameter is 4 mm. The probe diameter is 10 mm.
5. Mount the duct flange on the duct with screws.
6. Push the transmier probe into the duct through the hole on the flange. Make sure that the cable glands of the transmier point down. See the figure below for the correct mounting orientation.
7. Adjust the probe to the correct depth. Make sure that the air velocity sensor is in the middle of the duct.
   1. A. Air velocity sensor
8. Tighten the locking screw on the duct flange to hold the probe in position.

Wiring

• WARNING: Device wiring and commissioning can only be carried out by qualified professionals. Always make the device wiring in the de-energized electricity network.
• WARNING: Fuse at load supply (normally 6 A, 10 A, 16 A) does not always limit the relay output load current to 6 A. The relay maximum load is 250 Vac, 6 A res.
• WARNING: Add an external fuse to relay the common connector. Use a time-lag fuse (max 6 A) that is in accordance with the standard IEC 60127-2. The product does not have an internal fuse for the relays.
• CAUTION: The product may only be connected to an overvoltage category II electricity network according to IEC 60664-1.
• CAUTION: Use single-stranded wires or wire end sleeves if mul-stranded wires are used.
• Important: For CE and UKCA compliance, a properly grounded shielding cable is required.

The relay models (-R) and the Modbus (-MOD) models have two cable glands (the left and the right cable glands). Other models only have one cable gland (the left cable gland). See section Wiring for Modbus models (-MOD) on page 13 for Modbus model wiring instructions.

1. Open the cover.
   WARNING: Do not open the device cover when the relay mains supply voltage is connected. Always do the commissioning of the device in a de-energized relay electricity network.
2. Unscrew the strain relief on the left cable gland and route the cables for power in and signal out through the cable gland.
3. For relay models (-R), unscrew the strain relief on the right cable gland and route the cable for the relay through the cable gland.
4. Connect the wires according to the table below.
   

   Tout/B	Temperature measurement output signal: 0…10 Vdc, load > 1 kΩ 4…20 mA, load 20…400 Ω
   Vout/A	Air velocity measurement output signal: 0…10 Vdc, load > 1 kΩ 4…20 mA, load 20…400 Ω
   24V	24 Vac/dc supply
   GND	0 V
   NC	Relay output on -R models: 30 Vdc, 6 A / 230 Vac, 6 A res.
   COM
   NO

   • The nominal wiring terminal screw tightening torque is 0.4 Nm.
   • Important: Do not use excessive force when you tighten the wiring terminal screws.
5. Tighten the strain reliefs.

Wiring for Modbus models (-MOD)
Note: The -MOD models have Modbus communication instead of analogue outputs.

Important: For CE and UKCA compliance, a properly grounded shielding cable is required. It is recommended to use a shielded twisted pair cable for Modbus cabling. The cable shield must be earthed only in one point, usually at the end of the main cable.

1. Open the cover.
2. Unscrew the strain relief on the left cable gland.
3. Route the cables for power in and Modbus communication through the left cable gland.
4. To connect this device to the next device in a daisy chain network:
   1.  Unscrew the strain relief on the right cable gland.
   2. Route the Modbus cable to the next device through the right cable gland.
5. Connect the wires according to the table below.
   

   Tout/B	Modbus RTU (RS-485)
   Vout/A
   24V	24 Vac/dc supply
   GND	0 V

   • The nominal wire terminal screw tightening torque is 0.4 Nm.
   • Important: Do not use excessive force when you tighten the wiring terminal screws.
6. Tighten the strain reliefs.

Warm-up mode
This device starts up in warm-up mode. The warm-up mode continues for 15 seconds after startup. During the warmup time, the output signals are at the defined minimum values and the relay does not operate. If the device has a display, text Warming up is shown on the display. The device starts to operate correctly after the warm-up time.

Configuring settings via device menu

• See the figure below for the full menu structure for all models with display (-D) excluding the Modbus models (-MOD).
• For the Modbus model menu structure, see the section Available settings for Modbus on page 19.

• A. SELECT button
• B. UP button
• C. DOWN button

1. Open the cover.
   WARNING: Do not open the device cover when the relay mains supply voltage is connected. Always do the commissioning of the device in de-energised relay electricity network.
   CAUTION: When the power supply is connected, be extra careful when handling the product without the cover.
2. Press the SELECT button for two seconds to activate the device menu.
3. Use the UP and DOWN buttons to navigate the menu.
4. Press the SELECT button to change the value of a menu item.
5. Press the UP or DOWN button to select a value.
6. Press the SELECT button to accept the new value and to return to menu navigation.
7. Navigate to the EXIT MENU view and press the SELECT button to save the setings and exit the menu.

Available settings for velocity and temperature
For Modbus model settings, see chapter Available settings for Modbus on page 19.

• The Vel. unit menu
  • You can select the velocity unit for the device display and the velocity output in the VEL. UNIT menu.
  • The available velocity units are m/s and ft/min. The default value is m/s.
• The Temp. unit menu
  • You can select the temperature unit for the device display and the temperature output in the TEMP. UNIT menu.
  • The available temperature units are °C and °F. The default value is °C.
• The PID in use menu
  • You can select if the PID control function is in use in the PID IN USE menu.
  • The available values are no and yes. The default value is no.
  • If you select no, the next menu item is V RANGE MAX.
  • If you select yes, the next menu items are REFERENCE SP, P-VALUE, I-VALU,E and D-VALUE.

THE V RANGE MAX MENU

• You can select the maximum value for air velocity measurement range in the V RANGE MAX menu.
• You can select the maximum velocity measurement range between 1 m/s and 20 m/s. The default value is 10 m/s.
• If you selected ft/min in the VEL. UNIT menu, you can select the maximum velocity measurement range between 200 ft/min and 4000 ft/min. You can adjust the value by 200 ft/min steps. The default value is 2000 ft/min.

THE REFERENCE SP MENU
You can select the setpoint for the PID controller in the REFERENCE SP menu. You can adjust the value by 0.1 m/s or 1 ft/min steps depending on the selected air velocity unit. The default value is 5 m/s or 1000 ft/min.

THE P-VALUE, I-VALUE AND D-VALUE MENUS

• You can select the proportional gain in the P-value menu. You can adjust the value by 0.01 unit steps. The default value is 1.00.
• You can select the integral gain in the I-value menu. You can adjust the value by 0.01 unit steps. The default value is 1.00.
• You can select the derivative gain in the D-value menu. You can adjust the value by 0.01 unit steps. The default value is 1.00.
• You can select the P-value, I-value and D-value between 0 and 99.99.

THE V UUT SCALE MENU

• You can select the air velocity output scale in the V OUT SCALE menu.
• The available values are 0-5 V, 0-10 V, 2-10 V and custom. The default value is 0-10 V.
• If you select custom, you can set the minimum and maximum values for the air velocity output scale.

THE V OUT MIN MENU

• If you selected custom in the V OUT SCALE menu, you can select the minimum value for the air velocity output scale in the V OUT MIN menu.
• You can select a value between O V and 10 V. You can adjust the value by 1 V steps. The default value is 0 V.

Note: You can select a minimum value that is bigger than the maximum value to reverse the operating direction.

THE V OUT MAX MENU

• If you selected custom in the V OUT SCALE menu, you can select the maximum value for the air velocity output scale in the V OUT MAX menu.
• You can select a value between O V and 10 V. You can adjust the value by 1 V steps. The default value is 10 V.
• Note: You can select a maximum value that is smaller than the minimum value to reverse the operating direction.

THE T RANGE MIN MENU

• You can select the minimum value for temperature measurement range in the T RANGE MIN menu.
• You can select a value between -25 °C and 40 °C. You can adjust the value by 5 °C steps. The default value is 0 °C.
• If you selected °F in the TEMP. UNIT menu, you can select a value between -13 °F and 104 °F. You can adjust the value by 2 °F steps. The default value is 32 °F.

THE TRANGE MAX MENU

• You can select the maximum value for temperature measurement range in the T RANGE MAX menu.
• You can select a value between -15 °C and 50 °C. You can adjust the value by 5 °C steps. The default value is 50 °C.
• If you selected °F in the TEMP. UNIT menu, you can select a value between 5 °F and 122 °F. You can adjust the value by 2 °F steps. The default value is 122 °F.

THE T-OUT SCALE MENU

• You can select the temperature output scale in the T OUT SCALE menu.
• The available values are 0-5 V, 0-10 V, 2-10 V and custom. The default value is 0-10 V.
• If you select custom, you can set the minimum and maximum values for the temperature output scale.

THE T OUT MIN MENU

• If you selected custom in the T OUT SCALE menu, you can select the minimum value for the temperature output scale in the T OUT MIN menu.
• You can select a value between O V and 10 V. You can adjust the value by 1 V steps. The default value is 0 V.

Note: You can select a minimum value that is bigger than the maximum value to reverse the operating direction.

THE T OUT MAX MENU

• If you selected custom in the T OUT SCALE menu, you can select the maximum value for the temperature output scale in the T OUT MAX menu.
• You can select a value between O V and 10 V. You can adjust the value by 1 V steps. The default value is 10 V.

Note: You can select a maximum value that is smaller than the minimum value to reverse the operating direction.

Relay settings

THE RELAY DIR MENU

• This menu is shown only if the transmitter has a relay output (-R models). Relay operating direction defines if the relay switches on or off when the air velocity is more than the setpoint value.
• You can select the relay operating direction in the RELAY DIR menu. The available values are Rise and Fall. The relay switches on if Rise is selected and the air velocity is more than the setpoint value. If Fall is selected, the relay switches on when the air
• velocity is less than the setpoint value. The default value is Rise.

THE RELAY SP MENU

• This menu is shown only if the transmitter has a relay output (-R models).
• You can set the velocity setpoint for the relay in the RELAY SP menu. You can set this value with an accuracy of two decimals. The default value is 5 m/s or 1000 ft/min.

THE RELAY HYST MENU

• This menu is shown only if the transmitter has a relay output (-R models). This setting defines how much the air velocity must drop below the setpoint before the relay switches off if Rise is selected in the RELAY DIR menu. The function is opposite if Fall is  selected in the RELAY DIR menu.
• You can set the hysteresis value for the relay in the RELAY HYST menu. You can select a value between 0.1 and 20.0 m/s. You can adjust the value by 0.1 m/s steps. The default value is 0.5 m/s.
• If you selected ft/min in the VEL. UNIT menu, you can select a value between 20 ft/min and 4000 ft/min. You can adjust the value by 20 ft/min steps. The default value is 100 ft/min.

THE EXIT MENU VIEW
Navigate to the EXIT MENU view and press the SELECT button to save the settings and exit the menu.

AVAILABLE SETTINGS FOR MODBUS
The figure below shows the menu structure for the Modbus models with display (-MOD-D). These menu settings are only available in the Modbus models.

The Baud rate menu

• You can select the bus speed in the BAUD RATE menu.
• The bus speed can be 9600, 19200 or 38400 bits/s. The default baud rate is 19200 bits/s.

The Address menu

• You can select the Modbus address in the ADDRESS menu.
• Address range is 1…247. The default value is 1.

The Parity bit menu

• You can select Modbus parity in the PARITY BIT menu.
• The available values for bus parity are none, odd and even. The default setting is none.

The Vel. unit menu

• You can select the velocity unit for the device display and the velocity output in the VEL. UNIT menu.
• The available velocity units are m/s and ft/min. The default value is m/s.

The Temp. unit menu

• You can select the temperature unit for the device display and the temperature output in the TEMP. UNIT menu.
• The available temperature units are °C and °F. The default value is °C.

The Exit menu view
Navigate to the EXIT MENU view and press the SELECT button to save the settings and exit the menu.

Locking the cover
WARNING: There is a hazardous voltage inside the R-model devices. Always lock the cover before the relay mains supply voltage is connected.

1. Close the cover.
2. Tighten the cover locking screw (-R models).
3. Make sure that the cover does not open without tools.

Maintenance

Cleaning the probe and the sensor element

• Dust, grease and other dirt can accumulate on the sensor element over time and decrease the measurement accuracy of the sensors. Clean the probe and the sensor element regularly. The required cleaning interval depends on the air cleanliness.
• Do not clean the sensor element with detergents or other chemicals.

1. Disconnect the device supply voltage. For the -R models, disconnect the device supply voltage and the relay mains supply voltage.
2. Clean the probe with a soft cloth.
   1. A. Probe
   2. B. Sensor element
3. Clean the sensor element with compressed air. Apply compressed air lightly to the sensor element to prevent damage.

Important: Do not use too high pressure, touch the sensor element or use other cleaning methods that cause mechanical stress. Mechanical stress damages the sensor element and changes the measurement accuracy of the sensors.

Modbus

Modbus properties
The Modbus communication is only available in -MOD models. The parameter memory durability allows at least 1,000 writing cycles.

Note: The changes to the Modbus communication settings take effect after you restart the device.

• Protocol RS-485 Modbus RTU
• Bus speed 9600/*19200/38400 bit/s
• Data bits 8
• Parity *none/odd/even
• Stop bits 1
• Modbus ID 1*
• Unit load 1/8 UL * factory setting

Modbus function codes
The device supports the following Modbus function codes.

Decimal	Hexadecimal	Function
3	0x03	Read Holding Registers
4	0x04	Read Input Registers
6	0x06	Write Single Register
16	0x10	Write Multiple Registers

Modbus registers
Input registers: General

Register	Parameter description	Data type	Values	Range
0	Velocity m/s	U16	0…2000	0…20 m/s
1	Velocity ft/min	U16	0…4000	0…4000 ft/min
2	Temperature °C	S16	-250…500	-25.0…50.0 °C
3	Temperature °F	S16	-130…1220	-13.0…122.0 °F
4…99	Reserved for future use

Device model details

Register	Parameter description	Data type	Values	Range
9800	Register count	U16	0…99	0…99
9801	Format version	U16	0…65535	0…65535
9802	Display	U16	0…1	0.     no 1.     yes

Register	Parameter description	Data type	Values	Range
9803	Buttons	U16	0…1	0.     no 1.     yes
9804	Number of relays	U16	0…1	0….1
9805	Analogue outputs	U16	0…1	0.     no 1.     yes
9806	Modbus	U16	0…1	0.     no 1.     yes
9807	Connector for	U16	0…1	0.     no 1.     yes
9808	PID controller	U16	0…1	0.     no 1.     yes

Device information

Register	Parameter description	Data type	Values	Range
9900	Device type	U16	0…65535	0…65535
9901	Hardware version	U16	0…65535	0…65535
9902	Production number, most significant word	U16	0…65535	0…65535
9903	Configuration number, least significant word	U16	0…65535	0…65535
9904	Configuration number, most significant word	U16	0…65535	0…65535
9905Configuration	number, least significant word	U16	0…65535	0…65535
9906…9908	Reserved for MyTool®	U16
9909	Ethernet MAC address 1	U16	0	0
9910	Ethernet MAC address 2	U16	0	0
9911	Ethernet MAC address 3	U16	0	0
9912	Wireless MAC address 1	U16	0	0
9913	Wireless MAC address 2	U16	0	0
9914	Wireless MAC address 3	U16	0	0
9915	Memory state	U16	0…9	0.     Idle 1.     Loading latest configuration 2.     Saving latest configuration 3.     Loading default configuration 4.     Saving default configuration 5.     Loading calibration 6.     Saving calibration 7.     Saving application state 8.     Chip erase in progress 9.     Cloud configuraon management
9916	Configuration compability number	U16	0…65535	0…65535
9917	Firmware ID, most significant word	U16	0…65535	0…65535

Register	Parameter description	Data type	Values	Range
9918	Firmware ID, least significant word	U16	0…65535	0…65535
9919	Firmware version (major, minor)	U16	0…65535	0…65535
9920	Firmware version (revision, build)	U16	0…65535	0…65535
9921…9923	Reserved for MyTool®	U16	25	25
9924	MyTool® compatibility number	U16	0	0. Compability number not assigned (feature is not in use)

Holding registers: Modbus

Register	Parameter description	Data type	Values	Range	Default
0	Bus speed	U16	0…2	0. 9600 1.  19200 2.  38400	1
1	Address	U16	1…247	1…247	1
2	Parity bit	U16	0…2	0.     none 1.     even 2.     odd	0
3	Velocity unit	U16	0…1	0.     m/s 1.    ft/min	0
4	Temperature unit	U16	0…1	0.     Celsius 1.     Fahrenheit	0
5…199	Reserved for future use

MyTool

Register	Parameter description	Data type	Values	Range	Default
200	PID in use	U16	0…1	0.     no 1.     yes	0
201	Velocity range max. (m/s)	U16	1…20	1…20 m/s	10
202	Velocity range max. (ft/min)	U16	2…40	200…4000 ft/min	20
203	Velocity control setpoint (m/s)	U16	1…2000	0.01…20 m/s	500
204	Velocity control setpoint (ft/min)	U16	2…4000	2…4000 ft/min	1000
205	Velocity control P factor	U16	0…9999	0…99.99	100
206	Velocity control I factor	U16	0…9999	0…99.99	100
207	Velocity control D factor	U16	0…9999	0…99.99	100
208	Velocity/velocity control signal scale	U16	0…3	0. 0…5 V 1. 0…10 V 2. 2…10 V 3. Custom	1
209	Velocity/velocity control signal scale custom min.	U16	0…10	0…10 V	0
210	Velocity/velocity control signal scale custom max.	U16	0…10	0…10 V	10
211	Temperature range min. (°C)	U16	-25…40	-25…40 °C	0

Register	Parameter description	Data type	Values	Range	Default
212	Temperature range min. (°F)	U16	-13…104	-13…104 °F	32
213	Temperature range max. (°C)	U16	-15…50	-15…50 °C	50
214	Temperature range max (°F)	U16	5…122	5…122 °F	122
215	Temperature output signal scale	U16	0…3	0. 0…5 V 1. 0…10 V 2. 2…10 V 3. Custom	1
216	Temperature output signal scale custom min.	U16	0…10	0…10 V	0
217	Temperature output signal scale custom max.	U16	0…10	0…10 V	10
218	Relay operating direction	U16	0…1	0.     Rise 1.     Fall	0
219	Relay setpoint (m/s)	U16	1…2000	0.01…20 m/s	500
220	Relay setpoint (ft/min)	U16	2…4000	2…4000 ft/min	1000
221	Relay hysteresis (m/s)	U16	1…2000	0.01…20 m/s	50
222	Relay hysteresis (ft/min)	U16	2…4000	2…4000 ft/min	100

Disposal
This device is considered as electrical and electronic equipment for disposal in terms of the applicable European Directive. At the end of life, the product must enter the recycling system at an appropriate collection point.

• The device must be disposed through channels provided for this purpose.
• The disposal must be completed according to the local and currently applicable laws and regulations.

Generally all metals can be recycled as material. Plastics and cardboard packaging material can be used in energy recovery. Printed circuit boards need selective treatment according to IEC 62635 guidelines. To aid recycling, plastic parts are marked with an appropriate identification code. Contact your local HK Instruments distributor for further information on environmental aspects and recycling instructions for professional recyclers.

WARRANTY POLICY

The seller is obligated to provide a warranty of five years for the delivered goods regarding material and manufacturing. The warranty period is considered to start on the delivery date of the product. If a defect in raw materials or a production flaw is found, the seller is obligated, when the product is sent to the seller without delay or before expiration of the warranty, to amend the mistake at his/her discretion either by repairing the defective product or by delivering free of charge to the buyer a new flawless product and sending it to the buyer. Delivery costs for the repair under warranty will be paid by the buyer and the return costs by the seller.

The warranty does not comprise damages caused by accident, lightning, flood or other natural phenomenon, normal wear and tear, improper or careless handling, abnormal use, overloading, improper storage, incorrect care or reconstruction, or changes and installation work not done by the seller. The selection of materials for devices prone to corrosion is the buyer’s responsibility unless otherwise is legally agreed upon. Should the manufacturer alter the structure of the device, the seller is not obligated to make comparable changes to devices already purchased. Appealing for warranty requires that the buyer has correctly fulfilled his/her duties arising from the delivery and stated in the contract.

The seller will give a new warranty for goods that have been replaced or repaired within the warranty, however only to the expiration of the original product’s warranty time. The warranty includes the repair of a defective part or device, or if needed, a new part or device, but not installation or exchange costs. Under no circumstance is the seller liable for damages compensation for indirect damage.

www.hkinstruments.fi

Information is subject to change without prior notice.

FAQ

Q: How do I select the output signal mode for the AVT air velocity transmitter?
A: The output signal mode can be selected during commissioning. Refer to the user manual for instructions on choosing between voltage (Vdc) and current (mA) modes.

Q: Can I use the AVT transmitter for temperature measurements only?
A: The AVT transmitter is designed for both air velocity and temperature measurements. For temperature-only applications, consider other specialized devices.

Documents / Resources

HK INSTRUMENTS RS-485 AVT Air Velocity Transmitter [pdf] User Guide RS-485 AVT Air Velocity Transmitter, RS-485, AVT Air Velocity Transmitter, Air Velocity Transmitter, Velocity Transmitter, Transmitter

References

• User Manual