Theben SELEKTA 170 top2, Manual

Page: 9 / 118

Page | 9
Zero-cross
switching Background:
Switch-on peak flows put a strain on the relays in the time switches and the
connected users.
Corrective measure:
The alternating voltage is monitored during zero-cross switching and the relay
switch-on delay is measured. The switch-on moment is accurately calculated by
software to ensure that the relay is connected exactly at the voltage zero-crossing
state. No inrush current peaks occur.

There is no overheating, no contact welding and hardly any contact wear.
Reset Reset is achieved by pressing all four buttons at the same time. By resetting, all
configuration settings (time format, 24 hours or AM/PM, etc.) are maintained.
However, date and time are deleted. The selection "Retain programs" or "Delete
program" is available. "Delete program" must be confirmed separately. With "Delete
program", all switch commands and the holiday program are deleted.
Priorities The following priorities are valid for the programmed switch commands, i.e. if
different switch commands were programmed in the same time period, the switch
commands with higher priority will be performed:
Cycle has the highest priority, followed by impulses;
switching times have the lowest priority