Abstract: The present invention intends to provide a small, low-cost, convenient transmitter system. The transmitter system detects physical quantities, converts the physical quantities into electrical signals, and allows the electrical signals to be transmitted to a load through a transmission line, comprising a main output circuit to be connected to a main instrumentation power supply and at least one subordinate output circuit to be connected to a subordinate instrumentation power supply.

Abstract: A memory updating system for a field device involves a fieldbus, one or more field devices that incorporate a nonvolatile memory and are connected to the fieldbus, a host system that is directly or indirectly connected to the fieldbus and transmits an updating instruction and updating data to one of the field devices in order to update the nonvolatile memory of the field device, and a current control circuit that controls a current provided from the fieldbus. The current control circuit increases the current provided from the fieldbus to a value greater than a normal value before the field device erases data stored in the nonvolatile memory, and returns the current provided from the fieldbus to the normal value after the field device completes the erasing of the data stored in the nonvolatile memory.

Abstract: A time difference signal having a pulse width corresponding to the time difference between an output of a resonant pressure sensor and a reference clock is prepared. The pulse width of the time difference signal is expanded by a given magnification. Based on a count value obtained by counting the reference clock during the expanded pulse width and a count value obtained by counting the reference clock during one cycle of the output of the resonant pressure sensor or a period which is integer times as long as the one cycle, the output frequency of the resonant pressure sensor is obtained. It is possible to obtain the fast processing and the high resolution without increasing the frequency of the reference clock.

Abstract: The present invention intends to provide a small, low-cost, convenient transmitter system. The transmitter system detects physical quantities, converts the physical quantities into electrical signals, and allows the electrical signals to be transmitted to a load through a transmission line, comprising a main output circuit to be connected to a main instrumentation power supply and at least one subordinate output circuit to be connected to a subordinate instrumentation power supply.

Abstract: A memory updating system for a field device involves a fieldbus, one or more field devices that incorporate a nonvolatile memory and are connected to the fieldbus, a host system that is directly or indirectly connected to the fieldbus and transmits an updating instruction and updating data to one of the field devices in order to update the nonvolatile memory of the field device, and a current control circuit that controls a current provided from the fieldbus. The current control circuit increases the current provided from the fieldbus to a value greater than a normal value before the field device erases data stored in the nonvolatile memory, and returns the current provided from the fieldbus to the normal value after the field device completes the erasing of the data stored in the nonvolatile memory.

Abstract: The present inventions overcomes a drawback that although it is necessary to increase frequency of a reference clock to perform the measurement of output frequency of a resonant pressure sensor speedily with high resolution, the increase of frequency gives rise to an increase of the power consumption and hence, the use of a two-wire differential pressure/pressure transmitter is difficult. A time difference signal having a pulse width corresponding to the time difference between an output of a resonant pressure sensor and a reference clock is prepared. The pulse width of the time difference signal is expanded by a given magnification. Based on a count value obtained by counting the reference clock during the expanded pulse width and a count value obtained by counting the reference clock during one cycle of the output of the resonant pressure sensor or a period which is integer times as long as the one cycle, the output frequency of the resonant pressure sensor is obtained.