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Type: |
Structure |
|
Available as of: |
V1.0.1.0 |
The Structure ST_TemperatureControl provides various parameters needed for the temperature control function block (FB_HeatingControl).
|
Name |
Data type |
Description |
|---|---|---|
|
rSetPointHighLimit |
REAL |
High limit for setpoint. Range: -100000 < rSetPointHighLimit ≤ 100000 [user-defined temperature unit] rSetPointHighLimit > rSetPointLowLimit Factory setting: 100 NOTE: Adjust the set point range to the requirements of the heating system and the working range of your application. |
|
rSetPointLowLimit |
REAL |
Low limit for setpoint. Range: -100000 ≤ rSetPointLowLimit < 100000 [user-defined temperature unit] rSetPointLowLimit < rSetPointHighLimit Factory setting: 0 NOTE: Adjust the set point range to the requirements of the heating system and the working range of your application. |
|
rPidHighLimit |
REAL |
High limit for the internal PID controller output. Range: Heating: rPidLowLimit < rPidHighLimit ≤ 100 % rPidLowLimit < rPidHighLimit ≤ 0 % Factory Setting: 100 % |
|
rPidLowLimit |
REAL |
Low limit for the internal PID controller output. Range: 0 % ≤ rPidLowLimit < rPidHighLimit Factory Setting: 0 % |
|
rPwmTimePeriod |
REAL |
Time period for PWM signal in [s]. This value scales the output q_rAnalogOutput to the PWM output q_xPwmOutput. Range: 5...60 s Factory setting: 10 s Example: If q_rAnlogOutput = 50 % of rPidHighLimit => On/Off time of q_xPwmOutput = 5 s |
|
rDigitalFilterTime |
REAL |
Filter time of the digital filter (noise reduction) in [ms]. If no value is given, the filter is not activated. A value less than the (determined) cycle time is not allowed. Refer to rDigitalFilterTime. Range: 0...100000 ms Factory setting: 0 ms |
|
rDeadBand |
REAL |
Dead band for the internal calculation of the control deviation. If the absolute value of the control deviation is smaller than the dead band, the control deviation is set to zero. Refer to rDeadBand. Range: 0...100 [user-defined temperature unit] Factory setting: 0 [user-defined temperature unit] NOTE: Any dead band value greater than 0 negatively influences the precision of temperature control. |
|
rAutoTuneHysteresis |
REAL |
Hysteresis value [% of user-defined temperature unit] for switching the heating on and off during auto-tuning is active. Refer to Hysteresis During Auto-tuning. Range: 0.1…0.5 % Factory setting: 0.2 % |
The values at these pins define the range of PID output. These values are configured as per the analog output module specification.The range is 0...100 %.
This dead band function is used to settle down the analog output of the function block.
Example:
rPwmTimePeriod := 10 s, rPidHighLimit := 100 %, rPidLowLimit: = 0 %, q_rAnalogOutput := 10.95 %
oPWM time on := 1.095 s
oPWM time off := 8,905 s
rSetPointHighLimit, rSetPointLowLimit
These values determine the range of i_rSetpoint. These values are decided with the minimum and maximum temperature which can be applied to the process so that it stops the temperature from increasing or decreasing then the desired limits.
If you get a noisy signal of the process value, you have to set the digital filter time. The filter is active when the digital filter time is greater than 0 ms. When the digital filter time is set, you get the medium process value for the entered digital filter time.
