| 摘要 |
PURPOSE:To prevent a sudden change without performing balancing operation during manual/automatic switching by supplying a manual resetting signal and a signal relating to a deviation signal to a holding circuit, which holds an output electrically during manual operation, during automatic operation. CONSTITUTION:A set-value and a process signal are supplied to terminals 30 and 33 to generate a deviation signal at the output of an operational amplifier 32, and the sum signal of the deviation signal and a signal from a manual resetting signal source 26 is outputted from an operational amplifier 41 and supplied to a connection point 25 through the parallel circuit of a resistance R20 and a capacitor C22. During automatic operation with a switch SW23 on and SWs 24 and 38 off, a C12 in an analog holding circuit 10 consisting of an operational amplifier 11, the C12, a manual operating means 13, and a drift compensating circuit 14 is charged to and held at an output V0. Then even when the connection point 25 and the output of an amplifier 10 are connected together through an R18, R20XC22=R18XC12, and the switches SW23, and SW24 and SW38 are turned off and on respectively for switching to manual operation, the output V0 is held, thus performing smooth switching without causing a sudden change in output. |
