PROCESSING METHOD FOR DEALING WITH RAM CONTENTS DECONSTRUCTION AND PROGRAMMABLE CONTROLLER

摘要

PROBLEM TO BE SOLVED: To prevent an erroneous operation when RAM contents are destructed by a capacity shortage or the like of a backup power source. ;SOLUTION: RAM contents detection data, a user program and data for set system are saved in a nonvolatile memory 3 and a RAM 4 and, when a power is supplied, the RAM contents detection data in the nonvolatile memory 3 and the RAM 4 are collated and non-coincidence by a capacity shortage or the like of a capacitor 9 is detected, contents in the nonvolatile memory 3 are written in the RAM 4 or the destruction of the RAM contents is reported to a user.;COPYRIGHT: (C)1999,JPO