| 摘要 |
PURPOSE:To improve the control efficiency and to prevent hunting for switching operation by adding mutual control functions between two, positive-direction and negative-direction PID operations and setting a hysteresis to master/slave switching of the control output. CONSTITUTION:A deviation (e) between a room temperature PV and a set temperature SP is operated in a deviation operating part 1; and if request discrimination of integral terma compensating operation results in affirmation in a positive-direction or negative-direction operation request discriminating part 5A or 5B, a positive-direction PID operating part 2' performs integral term compensating operation and PID operation on a basis of the deviation (e), and a negative-direction PID operating part 4' performs integral term compensating operation and PID operation on a basis of a value obtained by inverting the deviation (e) in a deviation inverting part 3. If request discrimination results in denial in discriminating part 5A and 5B, operating parts 2' and 4' perform only PID operation. When an output limit command is issued, positive-direction and negative-direction output limiting parts 6 and 7 use output lower limit values MLP and MLM as outputs MVP and MVM; but when the output limit command is released, parts 6 and 7 use outputs MCP and MCM of operating parts 2' and 4' as outputs MVP and MVM. If the output of each operating part is smaller than the value obtained by subtracting a hysteresis quantity from the lower limit value, master/slave switching is performed by a master/slave switching part 5E. |
