SMI

The automation of roller shutters and sun blinds in building automation is simplified with the SMI-Bus system (Standard Motor Interface). With SMI drives roller shutters can drive to precise positions and blind drives can drive to angular positions with an accuracy of a degree. The SMI drives can transmit actual positions, error messages and service information back to the SMI master terminal.

Major European manufacturers have joined forces in the SMI working group and have developed the digital interface. Drives are controlled by means of telegrams via this uniform interface. Using standard commands, functions can be implemented that are not so easy to realize with conventional drives. Examples are the precise movement to positions, the feedback of the current position and diagnosis. For the adjustment of louvers in shading systems, for example, angular resolutions of 2° can be achieved. Adjustment of the louvers in relation to the position of the sun is thus possible for constant light control. Powerful PLC function blocks are available in the TwinCAT HVAC library for room automation according to VDI 3813.

Distances of up to 350 meters between the controller and the drive are possible. A normal 5-core power cable can be used for the cabling (with PE, N, L and the SMI-specific I+ and I-); I+ and I- are protected against pole reversal. Up to 16 drives can be connected in parallel and addressed individually. SMI drives are available for mains voltage (230 V AC) and for low voltage (24 V DC).

In order to ensure the compatibility of the SMI products with one another, all products that are to be marked with the SMI logo must be certified. A positive certification can be read on the SMI Group’s homepage (https://standard-motor-interface.com). Further information on the SMI-Bus and SMI drives can also be found there.