A flexible safeguarding system for experimental set-ups

A modular safeguarding system is described. It has only two elements, a sensor module and a command module. It is assumed that the sensors have a normal output state corresponding to a closed switch contact. Each sensor module passes on the state of a sensor by multiple (electrically independent) relay contacts. Each device is activated by a command module with two sensing circuits which are wired through the appropriate sensor modules. Overruling of the output of a sensor module in an 'unsafe' state is possible by means of a front panel switch. This is indicated by a panel light, and the input, i.e. the state of the sensor, is still indicated. Designing and wiring a safeguarding system is very simple and the experimenter need only design the system logic, i.e. decide for each command module the sensor modules on which the operation of the device depends.