| 摘要 |
<p>A fast microprocessor (102) samples, through multiplexers (118a, 118b) repeated sequences of measured values (119a) and set values (119b) for a number of control channels. The fast microprocessor utilises a control programme to give control outputs (128) for each channel to regulate plant operation according to predetermined parameters. The parameters are input via a switchable two-part RAM (114) shared by the fast microprocessor and a general purpose microprocessor (104) linked to a key pad (108) through which new replacement parameters can be entered. When replacement parameters are required the fast microprocessor (102) swaps its inputs between the two parts of the RAM (114) so that each microprocessor uses the part previously used by the other, the swap being initiated by an instruction from the user via the keypad (108) but executed only by a swap signal from the fast microprocessor (102) timed to avoid interfering with the control program.</p> |
