| 摘要 |
<p>PURPOSE: To reduce the burden of a controller that is needed for tracing the input/output data in an automatic control system which includes two transmission modules to relay the data between the controller and a signal converter that inputs and outputs the signals to and from a controlled system. CONSTITUTION: A direct connection is secured between two transmission modules 2A1 and 2A2 via a 3rd signal bus 4, and the modules 2A1 and 2A2 include the traced data areas where the traced data can be stored in a fixed period. Then the traced data which are inputted to the operating one of both modules 2A1 and 2A2 are stored in its traced data area based on the trace condition and the trace start signal sent from a controller 1A. Furthermore, these stored data are transferred into the traced data area of the other module via the bus 4. When the tracing is needed for the input/output data, the controller 1A traces the data by means of the traced data on the non-defective on of both modules 2A1 and 2A2.</p> |
