Last edited: 28/01/2019
By default the two Sonoff Dual outputs can be activated simultaneously. This behavior can damage the motor. Therefore it is necessary to activate the interlock on the two outputs so that only one is active at a given instant.
The Sonoff Dual does not have a hardware iterlock. However the Tasmota firmware adds the possibility to activate a software interlock.
To activate it just go to the Sonoff Dual web page and write this command at the end of the ip address:
/cm?cmnd=SetOption14%201
For example if the IP address of Sonoff is 192.168.1.5, the full url will look like this:
http://192.168.1.5/cm?cmnd=SetOption14%201
WARNING: Starting from Tasmota version 6.4.1.11 the SetOption14 command is deprecated. In this case use the Interlock command:
http://192.168.1.5/cm?cmnd=Interlock%201
For more information on the available commands, visit the official page.
After typing the command, just press Enter. Then go back to the main Sonoff web page and check that the two outputs do not activate simultaneously.