Safety circuit preventing overload condition in e.g. fork lift truck - uses CPU to address force, load detectors and jib length detectors, and issue cut=off signals to relays in power circuits

摘要

A central processing unit is connected to a display cabinet while a bus circuit connects the CPU to a number of electronic circuits coupled to detectors in an addressable configuration. The bus also connects to a number of potentiometric or strain gauge sensors through coding circuits. These provide signals such as force, load and jib length to the CPU. The signals are such that variation in amplitude current or voltage is sensed by comparators and they are rejected if they are too high or too low. Detectors sense if the potentiometric or strain gauge circuits are broken and a relay cut out circuit prevents operation until a qualified person resets the system.