| 摘要 |
PURPOSE:To execute simply a test among slave stations and a master station by providing additionally a state input test circuit comprising an exclusive OR element and a switch into a circuit constituting slave station devices. CONSTITUTION:The state input test circuit T comprising the exclusive OR elements 1E-nE and the switches 1S nS is provided corresponding to state contacts 1-n of devices belonging to the slave stations. Since the switches 1S-nS are turned off normally, an input ai of the elements 1E-nE is brought into an H level by a pull-up resistor (r), and since other inputs bi are at an H level when the state of the contacts 1-n is OFF, outputs ci of the elements 1E-nE go to L level, and when the switches 1-n are turned on, the outputs ci go to H level. In executing the state input test, when the switches 1S-nS are turned on, the outputs ci of the elements 1E-nE reach a level inverse to the actual state of the contacts 1-n. The outputs ci of the circuit T are converted into a serial signal at a paralley series converting circuit PS and transmitted to the master station. |
