| 摘要 |
A loop powered process instrument comprises a control system measuring a process variable and developing a measurement signal representing the process variable. An output circuit, for connection to a remote power source using a two-wire process loop, controls current on the loop in accordance with the measurement signal. A power supply is connected to the output circuit and the control system. The power supply receives power from the two wire process loop and supplies power to the control system. The power supply comprises a voltage regulator receiving loop power and developing a regulated output voltage and an adjustable shunt regulator controlling voltage supplied to the voltage regulator. |
