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Explanation:
The target temperature is 60 degree, PID calculation range is 10 degree, PID control dead area
is 0.2 degree, auto tune period changing value is 10. When the PID control works in normal
atmospheric temperature, the PID output terminal will heat the temperature from 28 to 100
degree, then the output stops, the temperature keeps increasing to 110 degree (max
temperature) as the remaining warmth. Then the temperature keeps decreasing to 60 degree,
the output starts to heat again to 70 degree and stops. The temperature increases a little then
decreases again. This process will repeat. Finally, the temperature will fluctuate close the
target temperature.
Note:
1. When the temperature reaches 100 degree and stops heating, the PID start bit D4002.7 will
not reset at once, it has delay before reset.
2. When the temperature reaches 100 degree and stops heating, the PID auto tune success bit
D4002.8 will be ON at once.
3. When it starts PID calculation, the PLC will auto set a sampling time (about 2500). This
parameter will be replaced by the PID best sampling time after stoping heating at 100 degree.
4. When it starts PID calculation, the PLC will auto set the PID parameters (P=4454, I=926,
D=2317). These parameters will be replaced by the best PID value after stoping heating at
100 degree.
5. When the temperature reaches 100 degree and stops heating, the PID start bit D4002.7 will
not reset at once, it has delay before reset. At this time, the sampling temperature is higher
than target temperature. If user sets ON the PID auto tune again, PLC will get all the PID
parameters as 0. Please set ON the PID after the temperature decreases under the normal
atmospheric temperature.
6. If PID auto tune start bit and auto tune success bit are power-off retentive, please set or
reset them propably to avoid calculation error when starting the PLC next time.
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