iGrow1400 - Programming Mixing Valves

With the iGrow1400 Controller, you can control a Mix-Valve type heating system.

Note: This equipment type requires 2 consecutive channels 1&2, 3&4, 5&6, etc. The first channel (odd numbered) must be wired to OPEN the valve, and the other (even numbered) to CLOSE it.

To program simply hit Enter/Menu -> Program Equipment -> Hit Enter/Menu to highlight Output -> NEXT to scroll over to Equipment type field -> hit + till you display MixV then hit Back.
 

 

In the first screen your programming options are Temp / Min / Max / Open Time.

Temp - Setting tells the iGrow1400 which temp probe is being used to measure the hot water supply to the greenhouse. Since you can have up to 5 temp probes connected, be sure to set this to the correct one.

Min - is the minimum water temperature of the supply pipe. If the supply water temperature ever goes below this value the mix-valve will adjust increase the supply water temperature. 

Max - is the Maximum temperature that the supply water should ever become. If the supply water temperature ever approaches this value, the mix-valve will adjust low the supply water temperature. This is especially important when PVC pipes are being used.

Open Time - Open Time is the time it takes for the mix-valve to go from fully opened to fully closed. Measure this time with a watch, add a few seconds, and then enter it into Open Time field.

 

Heat Turn On Delay - is the estimated time it takes for the heating system to affect the greenhouse temperature.  This is determined by taking a temperature reading with all heating & cooling equipment off and the mix-valve closed, then manually switching the mix valve open. Measure the time it takes for the ambient temperature within the greenhouse to rise 2 deg.

 

Use Pump - If you want use a pump associated with the mix-valve system, this is where you select which pump to control. You must use one Output Channel to control the pump.

For more information on how to setup the pump, see the Pump Control section of this manual

 

 

Shock Protect - Setting Shock Protect to Yes forces the mix-valve to open slowly, preventing an inrush of cold water into your boiler system. Shock Protect will work two different ways depending on whether or not you have a return temp sensor assigned below. Without a Temp sensor the iGrow1400™ will still protect your boiler by adjusting how quickly the valve opens based on how long it’s been since the valve was opened last. The longer the time, the slower it will open. If you do assign a temperature probe, then the iGrow1400™ follows the “if Temp(1) is less than some temp then only open some percentage”.  

 

if Temp(3) < 140°F limit to 5% open.  If you have a temperature probe, assigned as Temp1 in the example above, then these are the settings for the return water supply to the mix-valve. In this example, if the return water temperature is below 105°F then the mix-valve will only open 5% until the return temperature reaches the low temperature setpoint of the supply water temperature.

 

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 mix-valve Param from Hide to Show. For further information on activating these

 

PID control (enabled View) 

 

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.

 

Here is a LinkConn 1000 View of your Mix-Valve Programming  Screen which a provides a more simpler control view.

 

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