Lindab UltraLink® Controller FTCU

Introduction

The UltraLink FTCU is a highly accurate airflow controller. It measures the airflow with ultrasound and can be calculated and compensated to a very high accuracy within the whole airflow range. The method is very stable over time due to its design, which minimizes the contamination of the airflow sensors.

UltraLink FTCU offers the benefits of a modern demand controlled ventilation system with only a couple of UltraLinks together with Bluetooth sensors installed in your existing ventilation system. It provides significant advantages in terms of comfort and energy savings.

Overview

Application

The FTCU is suitable for measuring and controlling airflow and temperature. Communication is established with analog and/or digital signals using Modbus.

Design

The FTCU consists of a sensor body attached to a damper body with Lindab Safe gaskets. The display unit and actuator are mounted on a cup, allowing the FTCU to be insulated up to 50 mm. Two flow sensors are mounted on the sensor body and connected to a display unit, which is mounted on top of a shelf on the damper body. The sensor and damper bodies can rotate relative to each other, enabling optimal positioning of the sensors independently of the display and damper body orientation. Correct positioning of the sensor body after a disturbance is crucial for measurement accuracy (refer to pages 6-7 for mounting directions). For FTCU dimensions 400-630, a flange connects the damper and sensor bodies; this flange must be loosened by unscrewing a nut to allow rotation. The nut size is 10 mm for FTCU dimension 400 and 13 mm for dimensions 500-630.

Display Unit

Mounting

Please note

• Do not remove the transducers!
• Do not use transducers as handles when mounting the FTCU, as this may cause damage!
• Ensure the airflow arrow points in the direction of airflow.
• Rotate the sensor body to the correct position according to the "Table of mounting distance to disturbance" on pages 6-7.
• For FTCU sizes 400-630, loosen the flange nut to turn the sensor body into the desired position, then retighten the nut.
• Position the display for visibility from a suitable direction.
• Mount the FTCU into the air duct system following the mounting instructions for Lindab Safe.
• Once positioned accurately, fix the FTCU with screws to the damper body, similar to connecting ducts and fittings.
• Never use the FTCU on the outlet side of a duct fan. Place it on the inlet side, or use a flow conditioner if it must be placed on the outlet side.
• A longer distance to disturbance (longer straight duct before the UltraLink) increases measurement accuracy.
• The motor direction switch must always be set to "1" as supplied.
• Do not make any changes or adjustments to the motor or its end-stops.
• To manually turn the damper, press the manual override button on the motor and turn the damper shaft with an 8 mm wrench or similar.

Planning

Measurement accuracy depends on two main factors: distance to disturbance (longer distance yields higher accuracy) and transducer positioning (the first transducer should be placed at the inner radius of a fitting). The FTCU can be placed at a distance of two duct diameters (Ød) from a disturbance to achieve specified uncertainty. In some cases, mounting directly onto a fitting is possible, but may require corrections in the OneLink app. Obstructions like axial fans, silencers, or cleaning hatches are not allowed before the UltraLink in the airflow direction; cleaning hatches must be placed after it. These obstructions cause turbulence and airflow measurement errors.

Table of mounting distance to disturbance

The table below shows the impact of various disturbances and transducer placements on measurement uncertainty. Measurement uncertainty is expressed as ± % or X l/s, whichever is greater, for the specific product size.

Electrical Installation

Before starting

• Do not make any holes or connect screws to the FTCU body.
• The shelf, FTES, can be used for mounting equipment like electrical junction boxes or Regula Combi units.
• Never remove the blue electronics box.
• Never remove the transducers.

[Warning symbol] For cable connections, there are two options: use the premounted cable or connect directly to the PCB (Option A and B).

Option A: Connect to premounted cable

Connect the premounted cable in a junction box near the FTCU. Connect power and signal cables according to the color scheme on the premounted cable's label. For Modbus signal wires, keep the premounted cable as short as possible to maintain signal quality. Place the junction box close to the FTCU and cut the premounted cable to the shortest necessary length.

Option B: Connect directly on PCB

To access the circuit board terminals, remove the lid by pushing the two heels on the side of the blue box. To connect cords, puncture the rubber cable grommet on the backside of the display unit using an awl or a pointed object to ensure environmental tightness. Do not remove the blue box for this. Ensure cables are strain-relieved after connection and can be attached to the shelf using cable ties through cut-outs.

General information (option A and B)

Using other cables for Modbus signals may cause communication problems.

Analog connection

When using analog signals, connect the FTCU's analog out signals (AO1, AO2) to the RTU's analog in terminals. Connect the FTCU's analog in signal (AIN) to the RTU's analog out terminal. Ensure the cables are connected to the same analog ground.

Digital Connection (Modbus)

Connect the RTU's A terminal to the FTCU's -A, and the RTU's B terminal to the FTCU's +B. When connecting multiple FTCUs in series, ensure -A connects to -A and +B to +B to avoid Modbus failure. Use RS485 cables with twisted pairs and shield; do not supply power in the same cable unless it's designed for it. Connect signal ground to the "GND" terminal next to the shield (SH) terminal on the PCB, and then to the corresponding terminal in the RTU.

Connecting shield

The shield in the RS485 cable should be grounded at the transformer and then continuously connected to "SH" on all UltraLinks powered by that transformer. If multiple transformers are used, the shield must be broken at each transformer, so "SH" on each product only connects to ground at its respective transformer.

Biasing

The bus master must have biasing on -A and +B. This is standard for BMS controllers. If using a conventional computer with an RS485-USB converter, ensure the converter has a bias circuit. If communication fails, add 500-1000 Ω resistors from -A to GND and from +B to the 3V3 terminal for biasing. A 120 Ω termination resistor between -A and +B on the last UltraLink is recommended to prevent signal reflections.

Repeater

If the bus exceeds 300 meters or has more than 30 devices, an RS485 repeater (FDS-R) may be needed for efficient communication.

Power Supply

Transformer sizing

The required size of 24 V AC transformer(s) is determined by summing the power consumption [VA] of all components. The transformer power must exceed this total. Use only safety isolating transformers. The current demand (I) is calculated as: I = (P1+P2+...+Pn) / U [A], where Pn is the power consumption of each component [VA] and U is the voltage (24 V). If the current demand exceeds 6 A (approx. 150 VA for a 24 V AC transformer), use multiple transformers to prevent overheating.

Supply cable sizing

Supply cable wire size is determined by calculating the resistance per meter (R). The calculation assumes a voltage drop of 2 V in the supply cable: R(per m) = Udrop / (I * L) [Ω/m], where Udrop is the accepted voltage drop (2 V), I is the current [A], and L is the longest supply cable distance [m].

The graph below shows Wire cross section Area [mm²] as a function of Copper Resistance [Ω/m]. For example, with Udrop = 2 V, I = 4 A, and L = 20 m, R = 0.025 Ω/m, corresponding to a wire cross-section area of 0.7 mm².

Power consumption

The power consumption for sizing supply cables for an UltraLink® FTCU is 0.5 VA. It is not recommended to use a transformer with a capacity higher than 150 VA.

Commissioning

Commissioning is performed using the Lindab OneLink app. Download the app by scanning or clicking the QR code. Ensure a signal strength of at least 60% for a stable connection between the UltraLink and your phone/tablet. Log in with the factory PIN (1111) and adjust settings. If the device is near a disturbance, apply correction settings in the app to compensate for measurement uncertainty (see "Correcting flow measurement for installation close to disturbance" on page 14). Change the device PIN code as described on page 14.

Demand controlled room regulation via UltraLink

Lindab Ultra BT™ Room Control System (Installation of wireless sensors)

The Ultra BT system revolutionizes demand controlled ventilation at room level. It offers a 360-degree upgrade with integrated Bluetooth Technology, improving cost-efficiency, installation simplicity, and daily operations for optimal indoor climate.

Additional heating and cooling via analog signal

Control heating and cooling sources using UltraLink and temperature sensors. For more details on Ultra BT functionalities and commissioning, refer to the Lindab Ultra BT™ Commissioning instruction, accessible via QR code or link.

Display

The display provides useful information via a green status light and parameters shown on the LCD. A blue light indicates Bluetooth status: flashing every three seconds when standby, and every second when a device is connected. Short pressing the Mode button cycles through displayed parameters. A long press (over 5 seconds) accesses the configuration menu. Arrows at the bottom of the display indicate the current parameter type and unit.

Parameter structure

The information menu appears upon powering up, defaulting to airflow in m³/h. Parameters can be toggled using the Mode button. The available parameters include:

• Actual air flow (m³/h, l/s)
• Actual air velocity (m/s)
• Actual Temperature (°C)
• Damper position (%, 100% = fully open)
• Current set point (m³/h, l/s, m/s)
• FTCU ID number
• Flow rate set point max/min (visible only with analog control and flow rate as control variable)

Status light

Green status light:

• No light: FTCU is turned off.
• Flashing every 3 seconds: Motor is regulating to reach set point.
• Flashing every 1 second: A problem has occurred; error code will be visible in the display.
• Constant light: FTCU is turned on and functioning normally.

Blue status light:

• No light: Bluetooth is turned off or the FTCU is not equipped with it.
• Flashing every 3 seconds: Bluetooth is on standby and ready to connect to a mobile device.
• Flashing every 1 second: A mobile device has been connected to the FTCU.

Correcting flow measurement for installation close to disturbance

If installation near a disturbance is necessary, corrections are made via the OneLink app. Connect to the UltraLink, navigate to "Configuration" > "Device settings", and click "Disturbance settings". Input the type of disturbance and the distance to it. The app will then automatically correct the flow measurement.

ID-numbers

Each FTCU has a unique ID-number (1-239) based on the last three digits of its serial number, found on the product label and packaging. If multiple Modbus devices share an ID, it must be changed to ensure unique identification for communication. Disconnect other devices with the same ID before changing it via the display's "Con. Set" menu (page 15) or the OneLink app. The Modbus ID register is 4x001.

PIN code

UltraLink with Bluetooth requires a PIN code for access and settings changes. The default PIN is 1111. It is crucial to change this to prevent unauthorized access. The Bluetooth radio can be disabled by setting register 4x007 to 0. The PIN can be changed via the "OneLink" application or the display's configuration menu.

Settings for override

The FTCU offers two override functions: via bus or analog input (for 2-10V or 10-2V signals). Bus control (register 4x071=0) allows forcing the damper to fully open/closed or setting flow rate to minimum/maximum (registers 4x315, 4x316). Analog control (register 4x071=1) allows forcing the damper to fully closed, irrespective of the minimum angle setting.

Override function by bus

1. Normal mode: register 4x151 = 0.
2. Maximum flow rate setpoint: register 4x151 = 1.
3. Minimum flow rate setpoint: register 4x151 = 2.
4. Fully open damper position: register 4x151 = 3.
5. Fully closed damper position: register 4x151 = 4.

Overrides can be restored manually (register 4x151=0) or automatically after a timeout (register 4x150).

Analog override function

In analog mode (4x071=1), override is active if the input voltage range is 2-10V or 10-2V (4x500=2 or 3) and the control variable is flow rate (4x070=2). Override functions are: 1. Normal mode (input voltage ≥ 2 V). 2. Fully closed damper position (if input voltage is lower than register 4x511).

Firmware update

Regular firmware updates ensure optimal performance and the latest features. To update, open the OneLink app, log in, go to "Configuration" > "Device info", and click "Firmware update".

Maintenance

The FTCU requires minimal maintenance. Visible parts can be wiped with a damp cloth.

Configuration menu structure

Settings can also be adjusted via the OneLink app. The configuration menu is accessed by long-pressing the button (5 sec). Options include:

• Con.Set (Connection settings)
• Aln.Set (Analog In settings)
• Cancel (Return to information menu)

Toggle between options with a short press; long press to select. Within Con.Set, options include Protocol (Pr.), Baud rate (b.), Stop bits (bit.), Parity (P.), Modbus ID (Id.), PLA address (PLA.), ELA address (ELA.), Pin-code (Pi.), and Control by bus (Cnt.). Use "Store" to save changes and "Cancel" to exit without saving.

Within Aln.Set, options include Max flow (qH.), Min flow (qL.), and Voltage range (r.).

Digital communication settings

Registers 4x001-4x009 configure communication settings. Default settings are active upon initial contact. These include Modbus ID (last three digits of serial number), Baud rate (19200), Parity (Odd), and Stop bits (1). Changes to communication parameters require a power cycle.

Control settings

The FTCU can be controlled via analog or digital (Modbus) signals. Key registers include 4x070 for set point type (0=no control, 1=damper position, 2=flow rate) and 4x071 for Modbus control (0=bus, 1=analog). Set points are applied using registers 4x302 (damper position) and 4x314 (flow). Damper position limits are 0-100%. Flow limits have default values but can be adjusted via registers 4x315 and 4x316. Default maximum flow values ensure guaranteed accuracy.

Refer to the appendix for Modbus register instructions. Settings can be changed via RS485 bus or the OneLink app.

Analog communication settings

Analog in settings via modbus

For analog communication (4x071=1), specify the operational voltage range and corresponding max/min values. Configure register 4x500 for analog input level (0-10V, 10-0V, 2-10V, or 10-2V). Configure registers 4x501-504 with max/min levels for the selected voltage range, depending on whether the device is controlled by angle (4x070=1) or flow (4x070=2). If set points are controlled via bus, this step can be skipped.

* 0% means fully closed damper position and 100% means fully open damper position.

Analog out settings via modbus

Analog out is always active. Specify data for the two ports: Configure registers 4x401 and 4x431 for variables (0=Flow, 1=Temperature, 2=Damper position, 3=Cooling, 4=Heating). Configure registers 4x400 and 4x430 for analog out level (0-10V, 10-0V, 2-10V, 10-2V). Configure registers 4x401-409 and 4x431-439 with max/min levels for the selected voltage range and variable.

Analog Out 1 Default Values:

Analog Out 2 Default Values:

* 0% means fully closed damper position and 100% means fully open damper position.

Refer to the appendix for Modbus register instructions.

Troubleshooting

If digital communication fails, please verify the following before contacting support:

• Check Baud rate, parity, and stop bit settings match between master and UltraLinks (configurable via OneLink app).
• Ensure -A and +B connections are continuous and correctly wired across all devices.
• Avoid "star connection" bus layouts.
• Verify power supply cables are connected identically (G to G for 24V, G0 to G0 for GND) on all products and transformers.
• The shield must be continuous along the bus and grounded only at the transformer and the last UltraLink.
• Limit devices per bus to 30; use a repeater if necessary.
• Bus length should not exceed 300 m; use a repeater for longer runs.
• Test communication with a PC using a Configuration Tool and a biased RS485-USB converter.
• Keep stub lengths (e.g., premounted cables) to a maximum of 20 meters for a 30-device bus.

If analog signals fails, make sure to doublecheck the following:

• Measure voltage on the screw terminal; it should match the BMS controller's voltage.
• If voltage is incorrect, check wire attachment to the UltraLink terminal. A loose connection may prevent signal pickup.

Problems accessing UltraLink via Bluetooth

• Ensure the UltraLink has the Bluetooth logotype on its display lid.
• Input the correct PIN code (default: 1111) to connect. Verify the PIN with an administrator if connection fails.

I cannot find the sensor model I'm trying to pair

Ensure you have the latest firmware installed on your UltraLink (see "Firmware update" on page 14).

Error codes

If an error occurs, the status light flashes, and an error code appears on the display. The table below lists common error codes, their problems, and solutions.

Cloud-Based Troubleshooting Support

Lindab offers cloud service for uploading OneLink data to assist with resolving issues. Contact your local Technical Support Team for this service.

Technical data

Technical data table

Airflows

Appendix A – Modbus register

This appendix details the Modbus registers available for the UltraLink. Each entry includes Address, FTCU/FTMU availability, Name, Description, Data type, Unit, Div (scale factor), Default value, Min/Max allowed values, and Access (Read Only/Read Write).

INPUT REGISTERS

Damper info

Alarms

Other

Sensor

HOLDING REGISTERS

Communication settings

System configuration

Override configuration

Damper

Analog output

* 0% means fully closed damper position and 100% means fully open damper position.

Analog input settings via modbus

For analog input settings (relevant when register 4x071 is set to 1): Configure 4x500 for analog input level (0-10V, 10-0V, 2-10V, 10-2V). Configure registers 4x501-504 for max/min levels based on the selected voltage range and control variable (angle or flow). If set points are controlled via bus, these settings can be skipped.

Sensor

About Lindab

Most of us spend the majority of our time indoors. Indoor climate is crucial to how we feel, how productive we are and if we stay healthy.

Lindab's objective is to contribute to an indoor climate that improves people's lives by developing energy-efficient ventilation solutions and durable building products. Lindab also aims to contribute to a better climate for our planet by working sustainably for both people and the environment.

Lindab | For a better climate