LB-762 Controller Installation Manual
LAB-EL
3.7.3
Connection diagrams - actuator open-close
For open-close actuator control, 2 separate relay outputs are used. First relay controls ”open” action, the second one controls
”close” action. Both relays must be properly configured in controller.
Using the same method, one can control engine, instead of actuator. Additional external circuitry is required, to properly
switch engine rotation direction.
Rysunek 3.10: Scheme of connection of open-close actuators
3.8
Bus of digital servomotors BELIMO MP-BUS
LB-762 regulator is equipped with one connector used for connection of a bus of digital servomotors consistent with BELIMO
MP-BUS standard. By means of this bus the regulator permits operation of 1 servomotor configured in PP mode or from 1 to
8 servomotors in MP mode. The key advantage of MP-BUS bus as compared with analog controlled servomotors is important
simplification and reduction in the quantity of cabling (instead of 3 separate ducts from each servomotor to the regulator
only 3 wires are conducted in parallel to each servomotor), better diagnostics (the regulator is able to detect lack of correct
communication with the servomotor – e.g. in consequence of damage of servomotor, power supply unit or cabling) and more
precise servomotor positioning and reading of its actual position (digital data transmission resistant to interference).
For cooperation with MP-BUS bus suitable servomotors must be used, consistent with this standard. Before connection to
the system they require configuration – address setting. Default, factory servomotor setting permits operation in PP mode
(permitting communication only with one servomotor), use of a greater number of servomotor requires assignment of an
individual address to each one. Servomotor address setup procedure is described further in the manual.
MP-BUS bus is galvanically insulated from all other connectors of LB-762 regulator, in order to ensure greater immunity to
interference created by digital data transmission.
3.8.1
Servomotor power supply
LB-762 regulator does not supply power to servomotors – servomotors require a separate, own source of power supply 24V DC
or 24V AC (BELIMO servomotors can be powered by both direct and alternate current). In the case of AC power supply
polarization of power supply does not have any importance here, for DC power supply attention should be paid to correct
polarization (see scheme of connections).
The power supply unit can be one common for all servomotors – it must however ensure appropriate current efficiency (for
example for digital servomotor LM24A-MP maximum power consumption is 3W, what means 24W with 8 servomotors peak
power consumption; depending on the number and type of servomotors used appropriate power supply efficiency should be
considered).
For a system using both analog and digital servomotors, it is also possible to provide their common power supply from
one power supply unit - in such case one should connect contact GND of connector BELIMO PP/MP with contacts GND
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