Channels
For each channel, a Name and Start Date can be provided. If a timer has been specified as a Channel Timer in the Timers dialog, it can be assigned to the channel in the Timer drop down list. This associates the timer with the channel’s light cycle. If there is only one light in the grow room, the first channel associated timer governs the on time for the light. The ON time will change according to the growth phase. This tends to be sufficient for most situations. More than one light could be accommodated if they are physically isolated from each other. The channel can be enabled/disabled by checking the Enable checkbox. This is handy for temporarily shutting down a channel during active growth cycles to perform maintenance.
There are four tabs in the Channels dialogue.
Schedule
In the Schedule tab, nutrient mixing strengths, growth phase duration and photoperiod are specified for each required phase. Although Growth, Bloom and Final phases are available, specify only those required for the crop. To remove a phase from the schedule, set all nutrient values to zero.
The context of the phases is as follows:
- Growth - often referred to as the vegetative period after seedling transplant or startup
- Bloom - this is generally the phase when flowering and pollination occurs. However, it can be used for an advanced vegetative stage of leafy crops.
- Final - when fruit is set and matures
To enter nutrient mixing strength data for a phase, click on the phase, enter data in Edit schedule growth phase data text boxes and click on Change. The nutrient data entered should be the maximum strength to be used for the phase. A global setting in the Nutrientdialog is the maximum allowed for all channels. This is a check to help avoid excessive dosing both manually and when auto TDS dosing is implemented. Light cycle in hours and duration of the phase in days is also entered here.
pH mgmt
If a pH electrode has been installed for a channel and appropriate pH pumps/solenoids are also attached, automatic dosing can be enabled. If these conditions are met, check auto adjust pH. It is very important to carefully select the values for each of the remaining items in this tab.
- pH Setpoint sets the target pH.
- pH hysteresis sets the acceptable range around the pH setpoint. (if setpoint is 5.5 and hysteresis is 0.1 then the acceptable range is 5.4 to 5.6).
- Max change per dose sets the maximum acceptable pH change for a pH dose. This value is used to alter the dose amount once the system has sufficient historical pH change data to use. Because the composition of the nutrient changes continuously, HHS monitors and adjusts dosing dynamically.
- Maximum doses per day can be set to a low value until experience indicates the pH dosing is functioning as expected. It is a safety mechanism.
- Maximum dose sets the maximum allowable undiluted raw reagent that can be used for each pH dose. The raw value is calculated by HydroHomeSoft from the dilution specified in Options->Nutrient. pH dosing amounts will be restricted to this level even if a larger dose would still maintain the pH in the specified range.
- Flush water sets the amount of reservoir water to add to the pH dose before distribution to the channel. This ensures the mixing tank residual does not contain a significant amount of the reagent. There is always a small quantity (~5-7ml) left in the bottom of the mixing tank. It also ensures a good flow to the channel through the distribution tubing from the channel solenoid to the channel container. For longer tubing, a higher value should be selected. ¼” tubing has a volume of 5 ml/foot (16 ml/meter)
TDS mgmt
NOTE: This feature is in research stage. HHS will track and record TDS but does not yet have automatic adjustment. The following descriptions are informational only for this release and may change. Because the Phidget hardware has changed for this release, it was deemed prudent to make the release before completing this function. The term TDS (total dissolved solids) is used rather than EC (electrical conductivity) because it is in more widespread use in the industry. Conversion from one to the other is a matter of choice and/or convention in different countries and for different manufacturers of testing equipment. The conversion factor from milli-siemens to TDS can be set in the EC to TDS conversion drop down list for each channel.
If an EC electrode has been installed for a channel, auto adjust TDS can be enabled. The items in this tab are as follows:
- TDS Setpoint sets the target TDS. A different setpoint can be specified for each growth phase.
- TDS hysteresis sets the acceptable range around the TDS setpoint. (if setpoint is 750 and hysteresis is 20 then the acceptable range is 730 to 770
- EC to TDS conversion sets the TDS value for one milli-siemen.
System
The system tab contains important information for the automatic dosing of pH and EC/TDS. By specifying the Total volume and nutrient circulation Flow rate, the total system Latency can be calculated. pH and EC/TDS changes require sufficient time to reach peak and steady states. HHS uses the latency time to prevent pre-mature dosing and to calculate the average effect of each dose.
By checking Notify if refill volume = total system volume, HHS will indicate nutrients are ready to be changed by issuing a message on the main screen. The message can be cancelled in the Tools->Overrides dialog.
