초록 ▼

The operation of an electromagnetic valve is monitored by connecting the coil of the valve to a d.c. source for a period of time sufficient to permit the current in the coil to reach its maximum steady state value then disconnecting the coil to permit the current to fall and re-connecting the coil t

The operation of an electromagnetic valve is monitored by connecting the coil of the valve to a d.c. source for a period of time sufficient to permit the current in the coil to reach its maximum steady state value then disconnecting the coil to permit the current to fall and re-connecting the coil to the source again and measuring the current which is established in the coil.

대표청구항 ▼

A method of monitoring the operating state of an electromagnetic valve having a displaceable spool moved between first and second operating positions by energizing a coil; said method comprising the steps of connecting the coil of the valve to be monitored to an electrical d.c. source until the curr

A method of monitoring the operating state of an electromagnetic valve having a displaceable spool moved between first and second operating positions by energizing a coil; said method comprising the steps of connecting the coil of the valve to be monitored to an electrical d.c. source until the current in the coil rises from an initial reference value to reach a pre-determined maximum value, disconnecting the source from the coil for a pre-determined time sufficient to allow the current to decay to an intermediate value greater than the reference value but lower than the maximum value, re-connecting the source to the coil, measuring the current in the coil and determining from the measured value, the reference value and the maximum value whether the current is at a first or a second value representing the first or the second operating positions of the spool.