Programmable controller and programmable controller maintenance equipment

摘要

PURPOSE: To execute the instruction of the programmable controller corresponding to a special function unit even during the exchange of any function unit by deciding whether the function unit of an instruction object is just under exchanging or not and changing an instruction to the special function unit under exchanging into a system memory. ;CONSTITUTION: When detecting the ON/OFF of an input switch, an I/O port allocated to the input unit being an I/O unit 14 is not directly read but the copy of the value of the I/O port stored in a device memory 16 at the time of end processing is read. When it is desired to access an initial value memory 15A and a buffer memory 15B of the special function unit, however, the special function unit 15 is directly accessed and data stored in the unit memory 15A/ 5B in the special function unit 15 are read out or setting is changed. When changing the sampling time of an analog signal sent from a temperature sensor, for example, value is directly set in the memory 15A/15B.;COPYRIGHT: (C)1996,JPO