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16 - CONTROLS
Example: Two-stage unit with a 45°C setpoint. I = 0 and D = 0.
P
0,5
1
1,5
2
S U P P L Y
S E T P O I N T
16.3.3 - Adjusting the setpoint to the water supply with compensation on the water return (P141 = 3) :
► Aim :
Allow the control system to anticipate changes in load on the loop by monitoring for variations in the water inlet temperature.
► Action :
Adjusts the controller time delay.
► Principle :
The water return temperature is measured: θt0; evaporator in cooling mode, condenser in heating mode at time t0 then t0 + P151.
The calculated temperature variation [θt1 - θt0] is used to define the compensator coefficient.
The PID control polling time then becomes: remaining time × compensator coefficient.
Configuring the compensator coefficient: The compensator coefficient can be set to between 0.1 and 1. (Parameter P150)
- If the compensator coefficient = 1 → the function is disabled.
- If the water return temperature variation < 0.5°C → no compensation.
The compensator coefficient is maximum when the temperature variation = 10°C between each time ∝.
Compensator coefficient diagram :
Example with a compensation factor of 0.5
Controller time delay P148 = 100 seconds
Compensation time P151 = 10 seconds
Stage 1
Off
43
44
44,34
44,5
T E M P . : - x x . x °
Compensation effect
Stage 2
44
44,5
45,5
44,66
45,33
44,75
45,25
: - x x . x °
Stage 1
On
46
47
46
45,66
45,9
Temperature variation
85
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