| 摘要 |
<p>PURPOSE:To obtain the communication system for programmable controller capable of coping speedily with abnormality occurrence and is suitable for maintenance by providing a means which sends the node address at an abnormality generated node back to a transmission-side programmable controller and a means which records the contents of the abnormality generated at the node. CONSTITUTION:This system is provided with the means which sends the node address at the abnormality generated node back to the transmission-side programmable controller if abnormality such as a failure in communication occurs and the means 15 which records the contents of the abnormality generat ed at the node. For example, if abnormality occurs at a node B of a PC2, a sent packet is not discarded at the node B unlike before and a return packet containing a response consisting of address data at the abnormality generated node B is generated and sent back to the side of the PB1. Work RAMS 15 of respective nodes, on the other hand, are stored with abnormality history tables and if abnormality occurs, its abnormality history is written. Consequent ly, the communication system which can cope speedily with abnormality occur rence and is suitable for the maintenance is obtained.</p> |
