EU declaration conformity
Fan speed controller | Modbus RTU | 115 - 230 VAC | 5 A
Transformer fan speed controller with Modbus RTU communication for manually or demand-based fan speed regulation.
The supply voltage ranges from 115 to 230 VAC. It can be used for single-phase motors. The maximum motor current (combined) is 5 A.
Modbus communication is used to control the RTVS8 series. To adjust the requested fan speed, a Sentera HVAC sensor, potentiometer (SPV series), Modbus I/O module, or BMS system can be used. The fan speed can be adjusted manually or automatically based on the temperature, relative humidity, CO2 and air quality (TVOC).
The fan speed is controlled by gradually varying the motor voltage. The autotransformer technology produces a perfect sinusoidal motor voltage. This ensures that the motor runs quietly. The electrical noise from the autotransformers is reduced by a special impregnated coating.
Surface mounting is possible (IP54 protection).
Additional specifications and description
Transformer controllers are robust, easy-to-use, efficient and affordable speed control solution. Another major advantage of transformer-based control units is speed control without electromagnetic excitation in the motors. The products are therefore also recommended for noise-sensitive premises. What you get by a transformer fan speed controller is: silent motor operation, simple control in steps and a controller with a long service life at a reasonable price!
About the series
The RTVS8 is a 5-step speed control for use with single-phase HVAC fans or pumps. A single-phase transformer controls the fan speed by altering the supply voltage in five fixed steps. These steps are adjusted either manually or automatically. The transformer is equipped with an additional unregulated output for operating external equipment. The LED indicators on the front of the unit indicate its status.
For added safety and reduced risk of fire, the unit features a TK monitoring contacts. Fans with external contact leads must always be connected to a motor protection device.
What is more, besides using the proven in time transformer technology, this controller features Modbus RTU. It is a serial protocol derived from the master/slave architecture. It is extremely widespread in BMS and industrial automation systems thanks to its ease of use and reliability.
The unit can be controlled both in automatic mode or in manual mode. In manual mode, the unit functions as a 5-step controller. In automatic mode, the unit can be connected to a Sentera device allowing the unit to be used for demand-based ventilation. In manual mode, the requested fan speed is written in Modbus register 12. In automatic mode, a Sentera HVAC sensor, a DADCM 0-10 V module or SPV digital potentiometer is connected to the RTVS8 controller. The connected device can be specified via Modbus register 18. Fan speed is controlled via the connected device. So in automatic mode, fan speed can be controlled via a 0-10 V signal, based on temperature, relative humidity, CO2, air quality (TVOC), CO or the SPV-series potentiometer.
Forward or reverse
When automatic mode has been selected, forward or reverse mode can be set. Forward mode means that the fan speed will increase when the measured value increases. In reverse mode, fan speed will be reduced when the measured value increases.
The functionality of the extra, unregulated output (115 - 230 VAC, depending on the supplied voltage) can be selected via Modbus register 19. By default, it indicates alarms. It can also indicate motor operation or it can be controlled via Modbus register 15. In general it is intended for relay control.
Thermal motor protection
This fan speed controller can monitor thermal motor contacts (TK or thermal contacts measure temperature in the motor windings). In case of motor overheating, the TK monitoring function will disable the motor in order to prevent motor damage. If the motor is not equipped with TK contacts, the TK monitoring function must be disabled via Modbus register 14.
Automatic restart after power failure
In case of a power failure, this controller will automatically reset itself. When the power is restored, the motor will restart automatically.
This fan speed controller can be installed on a wall or panel indoors. Make sure that the fan speed controller can cool sufficiently. Preferably install it in a cool place, best not in direct sunlight. The enclosure is made of high-quality r-ABS VO (UL94) plastic. This material is flame extinguishing, very tough and offers good protection against impacts. It offers an IP54 protection against ingress dust and water.