| 摘要 |
PURPOSE:To discriminate the defect of each isolation transmitter with simple circuit constitution, by providing a switching element for diagnosing respectively the isolation transmitter to a common line. CONSTITUTION:When a low signal is given to both control terminals X, Y and relays 61, 62 are energized, each contact is closed, a current flows to the primary side of all photocouplers 3, 3A-3n, i.e., to input elements 31, 31A-31n via the common lines A and B, all output terminals D0-D7 must be at low level and a photocoupler at a terminal not being a low level s in failure. In bringing the control terminal Y to a high signal, all the output terminals D0-D7 must be at high level and a coupler at a terminal not being at high level is in failure. |
