Q) So what is a temperature influence anyway?
A) A temperature influence allows you to automatically adjust your temperatures based on conditions inside or outside your greenhouse.
Q) Why do we want to adjust temperature? We already have four temperature periods in the day. Isn’t that enough?
A) Sometimes it is. If that is the case, you can just skip this section. But often growers want to make changes automatically. For instance, if it is humid in the greenhouse, you might want to lower your cooling temperature so that you get more air exchange to get rid of the humid air. Or you may want to implement DIF.
Q) Wait a second. What is DIF?
A) According to Wikipedia, DIF is a greenhouse technique involving temperature control for the purpose of controlling plant internode length and thus elongation rates. Basically, DIF refers to controlling the difference between day and night temperature in a zone.
Q) Can I not just do that with my time and temperature settings in my periods?
A) In theory, you could. But you run into problems when it gets warm outside. You might not be able to cool enough in the greenhouse and your daytime temperature would climb above the cooling temperature. If you don’t adjust your nighttime temperature accordingly, it will mess up your DIF control.
Q) Yes, I can see that would be a problem. How can I get around that?
A) You could use your temperature influences and adjust your night time temperatures if your average daytime temperature was higher than you wanted.
Q) What other things can I use the temperature influence for?
A) Many growers want to do specific things for their crop. It would be impossible for us to come up with a complete list. Even if we did, growers are always trying something new so the list would be quickly outdated. The temperature influences program allows them to do all kinds of things.
Q) How would I set up a temperature influence?
A) We tried to make it as simple as we could by putting the description as a sentence. The sentence has a basic structure and you change values within the sentence to get what you want.
Q) Can you give me an example?
A) Sure. Remember the DIF explanation? You could set that up by setting up this sentence in your temperature influence control “ As period 1 average temperature ranges from 22.0° to 25.0° adjust period 2 heating temperature by 3.0°.
Q) I thought you said it was simple.
A) Actually, it is. period 1 is the day and period 2 is the night. So if your temperature during the day is high, we raise the night time heating temperature.
Q) Exactly how would that work?
A) Using the example given, if your daytime average temperature is 22.0° or lower, it falls out of the range we set and we do not adjust the heating temperature. If it is 23.0°, we raise the heating temperature by 1.0°, if it is 24.0°, we raise the heating temperature by 2.0°, and if it is 25.0°, we raise it by 3.0°.
Q) It looks like you are raising the temperature 1 degree at a time?
A) No, that was just done to make it easier to explain. The adjustments are made in tenths of a degree.
Q) What happens if the average gets above 25.0°?
A) Once it gets above the upper limit, it will not do any more adjusting. So even if the average temperature was to get to 27.0°, it would still adjust the heating temperature by 3.0°.
Q) What would happen if I have two influences on the heating temperature at the same time?
A) They would be added together. if the humidity is adjusting the heating temperature by 1.0° and the light intensity is adjusting the heating temperature by 1.5°, the total influence would be 2.5°.
Q) Are there limits?
A) Yes. For each temperature you want to adjust, you can set a maximum adjustment level. So in the example above, if the maximum adjustment was 2.0°, the total influences would be limited to the maximum adjustment.
Q) Can I only adjust my heating temperature?
A) No, you can adjust a bunch of temperatures. Let me give you another example, “As measured outside temperature ranges from 10.0° to -2.0° adjust minimum water temperature by 20.0°”. This will raise your minimum water temperature as it gets cold outside. If you click on the temperature influence, it will give you a complete list of what you can adjust.
Q) Are there other ways I can adjust temperatures as well?
A) There are a bunch of different ways you can do this. We only covered the temperature influences. You can also adjust temperatures when your lights turn on, when you are purging, when your custom control programs turn on, when your crop protection program is on or when you have an external override.
Q) Wait a sec. You lost me there. I am not sure what all these programs are for.
A) Do not worry about it. When you start to use those programs, the settings will be self-explanatory once you understand the concept. Let's look at one example. In your lighting control program, you will see a temperature adjustment line. It might say “While growing light is on, adjust minimum water temperature 1 in all periods by -10°". This means that whenever the lights are on, the water temperature will be lowered by 10°.
Q) Does this also have a range?
A) No. Since the lights are either on or off, we do not need a range. It will simply lower the minimum water temperature by 10° whenever the lights are on.
Q) I see we can adjust temperatures. Can we also adjust equipment?
A) Yes. We call them temporary overrides. You can override specific pieces of equipment under certain conditions.
Q) Can you give me an example
A) Just kidding. Let’s use Crop Treatment as an example.
Q) That would be good. I saw the tile for Crop Treatment but I have no idea what it is for.
A) Crop treatment allows you to put your greenhouse in a special mode while you apply fungicides or herbicides. It allows you to close the vents and shut off the fans while you are spraying and open the vents and turn on the fans to force an air exchange when you are done.
Q) How would I use a temporary override in this example?
A) Your crop treatment has four phases. Prespray is the time before you start applying your fungicides or herbicides and allows you to shut down your greenhouse ahead of time. Spraying is when you are actively applying the treatment. Wait is when you are waiting for the treatment to settle on the plant and Purge is when you are trying to force an air exchange so that it is safe for people to re-enter the greenhouse.
During the Prespray period, you may want to open the vents to get a bit of an air exchange before you start. Then you can use your temporary override to set a minimum vent position during this time. You could also override your curtain to be open during this period.
During the Spray and Wait periods, you would want to keep your vents closed and your curtain open. You do that by setting a Maximum vent position of 0% and a curtain position of 0% during these periods. Finally, during the Purge period, you would set a minimum vent position to force the windows open to get an air exchange.
Q) That is a lot of stuff. How do I keep track of it all?
A) All the equipment you control has a status showing what it is doing. If your equipment is overridden by one of your temporary overrides, it will show up in the status that it was temporarily overridden. Since these statuses are also graphed, you can look at your chart to see what exactly was going on.
Q) That all sounds cool. Is there anything I should watch out for?
A) Yes, you need to remember that these are overrides…which has a priority over normal control. If you are temporarily overriding your vents to be open to force an air exchange after a crop treatment, the vents will stay open regardless of how cold it gets in the greenhouse.