The AACUSP is a self-programmable, Analogue Linear Heat Detection (LHD) cable control unit. It provides monitoring for any of the AA range of LHD sensor cable, configuration of alarm and pre-alarm temperatures as well as enabling simple interface to a main fire alarm or BMS system.
Interface and Programming
The AACUSP provides LED indications as well as an LCD. Internal pushbuttons allow configuration without the need for a PC. Pre-Alarm and Alarm thresholds can be set through simple menu options with no need for any graphs or nomograms. Initial set-up is done by measuring and entering the calibration resistance of the sensor cable removing the need to know the sensor cable length. Volt free changeover contacts are provided inside the control unit for Pre-Alarm and Alarm signaling to a main fire alarm control panel or BMS system. A failsafe opto-isolated photo transistor fault output is also provided. No user controls are provided on the control unit. An isolated input is provided enabling remote reset functionality.
Operation
As well as monitoring the LHD sensor cable for changes in temperature, the control unit also monitors for open and short circuit faults along the cable ensuring notification if the cable becomes damaged. It is fitted with its own internal temperature monitor and should the temperature within the controller enclosure reach 100°C (212°F), an alarm will be signaled. Each control unit may have up to 500m (1640ft) of LHD sensor cable connected to it, acting as a single detection zone. When the LHD sensor cable and the control unit are installed in different areas, a suitable interposing cable can be used to make the electrical connection between them.