iGrow 1800 Installation Guide
Page91
Link4 (714) 524-0004
01/02 Valve1 MixV
Valve Type
Heat
Passive Stage Yes
Tune Range 40.0 F
Valve Type
This field defines the device to be either for Heating or Cooling.
Passive Stage
This only applies if the valve is for cooling. Assuming that the
Valve Type
is set to
Cool
, and if the
Passive
Stage
is set to
No
, then the cooling valve will be off, when the zone is in the “Passive Stage”., that is, not Active
Cool (AC). If the
Passive Stage
is set to
Yes,
the cooling valve is always active.
Tune Range
Tune Range is the allowable temperature range that the Mix Valve PID controller can change the water
temperature setpoint from the setpoint set by the heat/cool demand.
For PID control of the Mix Valve the two following pages must be activated. To activate these pages go to the
Advanced Settings menu and set MixValve Param from Hide to Show. For further information on activating
these screens see page 60.
01/02 Valve1 MixV
Water Temp P 2.00
I 0.05
D 0.00
01/02 Valve1 MixV
Inside Temp P 1.00
I 0.40
Disable No D 0.40
P, I, and D values
These parameters determine the reaction times of the valve as related to the difference between the target
temperature and the actual temperature.
The
P
value is a proportional number. The larger the value for
P
, the faster the valve will move when the
temperature differs from the desired value. The downside to increasing
P
is that it can result in increased
overshoot.
The
I
value makes adjustments to the valve position to reduce the temperature overshooting. The larger the
value, the less the temperature will overshoot the target. The downside is that the larger the
I
value, the slower
the reaction time as the temperature gets close to its target. Also, never adjust I to be zero as it will generate
errors.
The
D
value looks at the rate of change of the difference between the target and the desired temperature.. The
higher the number, the more the valve will move when the temperature differs from its target. Be very careful
when increasing this number.
Disable
Disable stops the zone feedback loop used by the PID control.
