SPD MBS (version 1)

Multi-stage protection circuits are used to produce MBS series surge protective devices (SPDs). They are used to protect communication circuits with M-bus interface. A gas-filled surge arrester is used as a rough protection in the circuits, while a transient voltage suppressor (TVS) or varistor, or a combination thereof, is used as the thin protection element.

Such a solution allows to achieve a high diverting ability, a sufficiently low threshold for the protection (SPD operating voltage) and a high response speed. The current protection stages together with isolation elements can be placed in a single compact case mounted on a DIN rail, 18 or 36 mm wide, given the relatively low discharge currents values (when compared with power supply circuits). 

SPD data are connected in M-bus series interface circuit. It’s worth mentioning that the protective circuit takes into account both the permissible impulse effects levels on the protected equipment, as well as internal protected circuits features and M-bus interface including rated current up to 1.5 A, rated voltage 48 V and transmission speed up to 1 Mbps transient voltage suppressor diodes provide dissipation up to 1500 W or up to 3000 W of pulsed power, depending on the components used. The device is available in versions with the ability to connect 1 or 2 differential M-bus protocol communication lines.