DOLD fault annunciators basically a fault annunciator. provide information on faults and conditions through lamps, buzzers or in the form of clear text, in the electrical installtions in buildings and industrial facilities. They also inform about the work operations that is to be done. DOLD fault annunciators reduce the time of fault finding that lies in particular plants and complex machine parts. Thus, downtimes in production plants are minimized and cost is saved. For complex applications, new-value and first-up annunciators and electronic clear text fault systems , apart from the simple electrical group fault are made available . When PLC or management systems are used it is extremely important to install fault alarm, acquisition independent of the process level which keeps control when in any case the plant control fails to avoid damages. Its applications are restricted to building monitoring and monitoring of plants and machinery of any kind.