All instrumentation systems pertaining to industrial process controls as well as domestic application involves automatic fault finding facility. This facility detects the faulty condition of the system and draws the operator's attention towards it and enables to take suitable remedial actions to ensure proper operations of the system. The main purpose of all FDI methods is to monitor the system operations and in case of faults, accommodate the source of faults, so that timely corrective actions are taken. Fault Detection simply involves a decision, based on the monitoring data as to whether there is a fault or the system is running normally. Fault Isolation is then executed to identify the type and location of a fault after the fault detection has triggered an alarm so that corrective actions can be made. These two steps are known as Fault Detection and Isolation (FDI). Fault diagnosis is referred to as the combination of fault detection, identification and isolation. It is one such method of Annunciation in which the activation of visual or mechanical variable takes place when a removed switch or device has been activated as a result of fault in certain systems and an audio alarm may also be associated with annunciations. This FDI system is defined and the existing technique is to detect & isolate the fault with online parameter programming facility. The main advantage of the proposed approach of Control System based fault detection and isolation is its low cost. Low cost in terms of components used makes affordable in terms of easy handling and maintenance and various sensors can be used to give different types of input signals to circuit. An additional advantage is that the real time system still works when the host crashes, the matter that increases the reliability of the system & Data-logging facility can also be provided. A data-logger captures any measurement values which can be represented by a voltage. Nowadays, sensors and transducers are available for, practically, any physical quantity. The function of data-logger is to capture and store a specified number of sensor measurement values at predefined intervals and transfer the data, including date and time to a PC in the form of file.