| 摘要 |
The invention relates to a field device for process instrumentation, in particular a measurement transducer (1), having an analog output (30) to which a two-wire line (10, 11) can be connected for transmitting an analog output signal (7). A unit (12a, 12b, 12c, 12d) galvanically separates the processor (5) from an analog output circuit. A read-back channel (12c, 15) for a pulse-width modulated digital signal (13), which is tapped behind an element (12b) for galvanic separation, is provided for monitoring the generation of the analog output signal (7), and a unit (18, 19) is provided for monitoring the analog output signal (7) for maintaining a specifiable maximum deviation from a reference signal (17), which is generated in the same manner as the analog output signal (7) by low-pass filtering from the pulse-width modulated digital signal (13). The novel monitoring unit has the advantage that, in particular in case of transient signals, error states can be detected more quickly and that appropriate measures for reacting to error states can therefore be taken in less time. |
