Abstract: A circuit is disclosed for fault-monitoring a microprocessor. The circuit includes an oscillator having an output signal of the same frequency as a test signal output of the microprocessor. The circuit also includes a binary counter. The microprocessor test output is coupled to the reset input of the counter and the oscillator is coupled to the counting input of the counter. The counter counts when the test signal does not correspond in frequency to the oscillator signal. A lower order output signal of the counter is used as a reset for the microprocessor and a higher order output of the counter is used to generate a fault indicating signal if the microprocessor has not resumed correct operation and to inhibit the microprocessor. The oscillator is coupled to the counting input of the counter through a logic circuit. The two outputs of the counter are coupled to another logic circuit which supplies the reset and inhibit signals to the microprocessor.

Abstract: An electronic controller having a detachably mounted front panel unit on which display devices and control elements are arranged is disclosed. By means of the control elements, the process variables and the control parameters are changed incrementally. Values of the control parameter, process variables, and the selected control parameter are indicated by the display devices. To provide a compact, independent front panel unit which can be removed from the main housing of the controller for protection against unauthorized operation, the front panel unit is provided with a slave microprocessor which is connected via a plug-in connector to a master microprocessor in the main housing. Because the master microprocessor operates independently of the front panel mounted slave microprocessor, the front panel unit can be removed without affecting the operation of the controller.

Abstract: A flow meter is disclosed which comprises a rotary piston carrying at least one magnet, and a measuring transducer. The transducer comprises a multiplicity of magnetic field-sensitive components arranged in correspondence with the path of motion of the magnet. The magnetic field-sensitive components are arranged in groups which are coupled to a respective pulse edge-sensitive circuit such as a monostable multivibrator. The flow meter of the invention is particularly applicable as a liquid flow meter for foods.