| 摘要 |
PURPOSE:To obtain a valve position detecting method which may allow an open or closed condition of a step flow control valve to be reliably confirmed without influence from service circumstances, by detecting the open or closed condition from a change in inductance of a coil. CONSTITUTION:When power is supplied to start a program, a high-potential period of output VA continues for a predetermined time. Then, a high-potential output VB is generated from B output port. When an input VZ to C input port becomes a high potential, the output VB becomes a low potential. A period of the low potential is counted by a register B. The count value corresponds to inductance of a coil 1. The inductance of the coil 1 at this time is compared with that before one step. When the register counts 2, the valve position corresponds to step 0, that is, a full-closed condition. |
