The Optical-Thermal Detector FI750/OT operates both by means of an optical sensing chamber based on
the principle of scattered light as well as with a rate-of-rise thermal sensor according to EN 54-5, Class
A1R. The analysis of the analogue values of both detection units and the integrated comparison of characte-
ristics of fire ensure safe fire detection.
The detector is designed for use on ADM loops with Labor Strauss/700 protocol. In the parameter settings
of the control panel, one of 4 sensitivity levels of the smoke detection unit can be selected, thereby adapting
the detector optimally to the respective application. A thermal-only operation is also possible.
Intelligent evaluation algorithms in the detector compensate for the impact of contamination of the optical
sensing system. As a result, the response sensitivity of the detector is kept constant for a long time, thus
constituting an effective measure for preventing false alarms. A fine-meshed protective grid protects the
sensing chamber against ingress of dust and insects. In addition, the design of the housing makes it more
difficult for dust to settle inside the sensing chamber.
The two multicoloured LED indicators with 360° visibility indicate the activated condition of the detector in
red and the test condition in green. An output for the connection of a remote indicator is available. The inte-
grated dual-isolator disconnects the loop at short circuit on the loop line.
By means of the Programming Unit FI750/PU, the address of the detector can be set in the range 1 to 240.
In addition, the programming unit allows for the reading-out of parameters, such as the level of contaminati-
on of the optical chamber, the default analogue value or the production date. Furthermore, in case of con-
nection to a compatible fire detection control panel, the detector can also be AUTO-addressed.
The detector is accommodated in a white housing and is designed for indoor mounting. In the thermal-only
mode the room height is limited to 7.5m
