| 摘要 |
PURPOSE:To automate the mode switching of a controller by comparing a process signal with the 1st reference value so as to output a manual or automatic mode signal and detecting the minimum value of the process signal and outputting its mean value from the maximum value. CONSTITUTION:Process signals S1-S4 are supplied to a comparison/selection device 19 through input terminals 10-13 and compared with the 1st reference value from a reference power supply 14. As the result of comparison, only process signals without error among the signals S1-S4 become inputs to a maximum value detection circuit 21 and a minimum value detection circuit 28. The circuit 21 detects the maximum value in the process signal without error and gives an output. Moreover, the differential amplifiers 22-25 make only the process signals without error in the process signals effective and subtract them from the 2nd reference value from the reference power supply 14 and amplify the result and supply an output respectively as each differential amplification signal. Then the maximum value is detected by a maximum value detector 26 and the result is subtracted from the 3rd reference value from the power supply 14 at the differential amplifier 27 and the minimum value of the process signals is outputted. An averaging circuit 29 averages the maximum/minimum values and gives the result. |
