| 摘要 |
PURPOSE:To diagnose the abnormal contents and abnormal points promptly by providing an RAS data in a part of the transmission data outputted from a process controller to each terminal and not updating the RAS data only in the case of abnormality. CONSTITUTION:As shown in a signal A, an abnormal signal '1' is set beforehand in a part of the RAS data and transmitted from a serial transmission equipment 12. Since optical remote input/output devices 20a-20b are normal, the transmission data B and C are rewritten from '1' to '0' with respect to the RAS data of a self data slot. But if there is disconnection at a point M, the optical remote input/output device 20c diagnoses it as an abnormal reception. This device does not rewrite a circuit abnormal signal, but rewrites an MPU abnormal signal '1' to an MPU normal signal '0', and transmits it to the next stage. Therefore, in the received data into a serial transmission equipment 13, as shown in a signal E, only the 3rd RAS data is not '0', whereby the circuit between the devices 20b and 20c can be diagnosed as abnormal. |
