52 mm diameter
The pressure indicator applies the resistance measurement principle. A sensor converts the measured pressure to a corresponding resistance value. A turning magnet ratio measuring movement measures this resistance value. This value is displayed by a pointer moving over a dial graduated in pressure units. The turning magnet movement for ration measurement comprises three stationary coils wound at 90
against each other, and a rotating permanent magnet disk in these coils are connected in a circuit for ratio measurement, so that the instrument is insensitive to on-board voltage fluctuations.
This means that the pointer travel is only a function of the magnitude of the current flowing through the measuring system.
A magnetic shield prevents effects of external magnetic fields, indication errors due to temperature changes are corrected by a compensating resistor. A dropping resistor is used to adapt the measuring movement to higher operating voltages (e.g. 24V).