SL-20 4-channel fire-alarm adapter for access control

The SL-20 unit serves to open fail-safe locks in case of a fire hazard signal from a fire alarm.
Fail-safe locks are locked when they have supply voltage and open when that supply is interrupted.
Fire alarm systems that provide only voltage-free outputs are hard to connect to access control systems because there is nothing to power the extra relay that has to be added in series with the fail-safe lock.

The SL-20 solves these problems and provides the following functions:

• 4 channels to be inserted between the access controller and the fail-safe locks
• each channel can be set for fail-safe locks or automatic doors with voltage-free inputs
• normally, the SL-20 channels just connect the 12V from the access controller to the fail-safe locks
• when the fire signal is active (short or open/settable) all 4 channels interrupt power to the locks
• when the SL-20 has no (battery) power, all 4 channels interrupt power to the locks
• the SL-20 has a sealed lead battery, which provides up to 8h autonomy in case of a power cut
• the SL-20 provides voltage-free monitor outputs for the following: input voltage (220V) present, battery voltage present, fire signal active.
• polarity of the fire signal is settable via jumper (short or open)
• the battery is protected against deep-discharge with a low-current circuit