15. Handy Instruction Design Examples 2. Use the adjusted parameter in D200~D219 to control temperature. The curve becomes as below: From the figure above, we can see that the temperature control after auto-tuning is working fine and we use only approximately 20 minutes for the control. z PID sampling time should be set the same with the cycle time of GPWM instruction, but its unit is 10ms, which is different from the unit 1ms of GPWM instruction. z Sampling time of PV should be set to 2 times more than the sampling time of PID, generally between 2s ~6s. z PID parameter table of S3 for 16-bit instruction: DVP-PLC Application Examples 15-25 Device No. Function Range Explanation :
Sampling time (T ) S (unit: 10ms) 1~2,000 (unit: 10ms) If T is less than 1 program scan time, S PID instruction will be executed for 1 program scan time. If T = 0, PID S instruction will not be enabled. The minimum T has to be longer than the S program scan time. +1: Proportional gain (K ) P 0~30,000 (%) If SV is bigger than the max. value, the output will be the max. value. +2: Integral gain (K) I 0~30,000 (%) +3: Differential gain (K ) D -3,000~30,000 (%) +4: Control direction (DIR) 0: automatic control 1: forward control (E = SV - PV) 2: inverse control (E = PV - SV) 3: Auto-tuning of parameter exclusively for the temperature control.
The device will automatically become K4 when the auto-tuning is completed and be filled in with the appropriate parameter K , K and K (not available in the P I D 32-bit instruction). 4: Exclusively for the adjusted temperature control (not available in the 32-bit instruction). 5: automatic control(with upper/lower bounds of integral value). Only supported by SV V1.2 / EH2 V1.2 / SA / _ _ SA V1.8 / SC V1.6 or higher version PLC. _ _