| 摘要 |
PURPOSE:To make it possible to accurately measure differential pressure even at the time of operation under a severe condition, by compensating span error by changing voltage, which is impressed to a bridge circuit of a differential pressure transmitting system employing a semiconductor pressure-sensing element, in accordance with line static pressure. CONSTITUTION:In the case of measuring differential pressure by a bridge circuit employing a semiconductor pressure-sensing element and transmitting a result as an electric signal, span error from variation in line pressure is compensated by changing bridge-impressed voltage in accordance with the line pressure by using second pressure-sensing element. For instance, between terminals 31 and 32 of a power source circuit of a bridge 30 containing a resistance 21 of a differential pressure measuring element, a constant current diode 33, a resistor 25 and second pressure- sensing element resistance 26 are connected in series. A voltage corresponding to the line pressure is impressed onto an operation amplifier 34 to control a voltage to be impressed onto the bridge 30. It is possible, by doing so, to accurately differential pressure without span error even at the time of operation under a severe condition. |
