| 摘要 |
PURPOSE:To reduce the setting error between controllers less than the arithmetic accuracy of the controller and to attain the bumpless switching with these controllers, by providing a pulse generator at the outside and using a high frequency pulse oscillated from the pulse generator as a reference pulse to change the set value within the controller. CONSTITUTION:The high frequency pulses 34a and 34b produced from pulse generators 14a and 14b are sent to pulse counters 18a and 18b or 18c and 18d and counted there through AND circuits 15a and 15c or 15c and 15d only while an increase switch 1 or a decrease switch 2 of a manual/automatic station 30 is kept pushed. The set value is changed with the programs of microcomputers 7a and 7b according to a prescribed algorithm respectively. In other words, the differences between the increase count values 32a and 32b of this time sampling and the preceding increase count values are obtained by differential units 35a and 35c. Thus the increase count values 36a and 36c of this time are obtained. In the same way, the decrease count values 36b and 36d of this time are obtained. These increase and decrease count values are supplied through the station 30. Then the difference between the increase and decrease count values is added to the preceding set value to obtain the set value 29 of this time. |
