Mode of operation: The final controlling device is comprised of three components: characterised control valve (CCV), measuring pipe with volumetric flow sensor and the actuator itself. The adjusted maximum flow (max) is assigned to the maximum positioning signal (typically 10 V / 100%). The final controlling device can be controlled communicative or analogue. The medium is detected by the sensor in the measuring pipe and is applied as the flow value. The measured value is balanced with the setpoint. The actuator corrects the deviation by changing the valve position. The angle of rotation α varies according to the differential pressure through the final controlling element (see volumetric flow curves).
Transmission behaviour HE: Heat exchanger transmission behaviour Depending on the construction, temperature spread, medium and hydraulic circuit, the power Q is not proportional to the water volumetric flow V (Curve 1). With the classical type of temperature control, an attempt is made to maintain the control signal Y proportional to the power Q (Curve 2). This is achieved by means of an equalpercentage valve characteristic curve (Curve 3).
Control characteristics: The velocity of the medium is measured in the measuring component (sensor electronics) and converted to a flow rate signal. The positioning signal Y corresponds to the power Q via the exchanger, the volumetric flow is regulated in the EPIV. The control signal Y is converted into an equal-percentage characteristic curve and provided with the Vmax value as the new reference variable w. The momentary control deviation forms the positioning signal Y1 for the actuator. The specially configured control parameters in connection with the precise flow rate sensor ensure a stable quality of control. They are however not suitable for rapid control processes, i.e. for domestic water control. U5 displays the measured volumetric flow as voltage (factory setting). As an alternative, U5 can be used for displaying the valve opening angle. It is always in reference to the respective Vnom, i.e. if Vmax is e.g. 50% of Vnom, then Y = 10 V, U5 = 5 V.
Definition: Vnom is the maximum possible flow. Vmax is the maximum flow rate which has been set with the greatest positioning signal, e.g. 10 V. Vmax can be set to between 30% and 100% of Vnom.
Creep flow suppression: Given the very low flow speed in the opening point, this can no longer be measured by the sensor within the required tolerance. This range is overridden electronically.
Opening valve: The valve remains closed until the volumetric flow required by the positioning signal Y corresponds to 1% of Vnom. The control along the valve characteristic curve is active after this value has been exceeded.
Closing valve: The control along the valve characteristic curve is active up to the required flow rate of 1% of nom. Once the level falls below this value, the flow rate is maintained at 1% of Vnom. If the level falls below the flow rate of 0.5% of Vnom required by the reference variable Y, then the valve will close.
Converter for sensors: Connection option for a sensor (active sensor or switching contact). The MP actuator serves as an analogue/digital converter for the transmission of the sensor signal via MP-Bus to the higher level system.
Parameterisable actuators: The factory settings cover the most common applications. Single parameters can be modified with the Belimo Service Tools MFT-P or ZTH EU.
Positioning signal inversion: This can be inverted in cases of control with an analogue positioning signal. The inversion causes the reversal of the standard behaviour, i.e. at a positioning signal of 0%, regulation is to Vmax, and the valve is closed at a positioning signal of 100%.
Hydraulic balancing: With the Belimo tools, the maximum flow rate (equivalent to 100% requirement) can be adjusted on-site, simply and reliably, in a few steps. If the device is integrated in the management system, then the balancing can be handled directly by the management system.
Manual override: Manual override with push-button possible (the gear is disengaged for as long as the button is pressed or remains locked).
High functional reliability: The actuator is overload protected, requires no limit switches and automatically stops when the end stop is reached.
Home position: The first time the supply voltage is switched on, i.e. at the time of commissioning, the actuator carries out an adaption, which is when the operating range and position feedback adjust themselves to the mechanical setting range. After this process the actuator moves into the required position in order to ensure the flow rate defined by the positioning signal.