| 摘要 |
A process instrument includes a transducer (12), a two wire interface (34a, 34b), a microprocessor (20), a digital to analog converter (22), a first control circuit (23a, 23b, 23c, 23d, 23e, 24, 26, 28, 30, 32), and a second control circuit (38). A current (IL) passing through the two wire interface indicates a condition of the transducer (12). The microprocessor (20) is interfaced with the transducer (12). The digital to analog converter (22) receives a signal from the microprocessor (20) indicating a current value. The first control circuit (23a, 23b, 23c, 23d, 23e, 24, 26, 28, 30, 32) is coupled to the digital to analog converter (22) and adapted to control the current (IL) passing through the two wire interface (34a, 34b) to the current value. The second control circuit (38) is coupled to the digital to analog converter (22) and supplies current to a secondary load (50). |
