Stacked Container Hydroponics for Vertical Farming : Blog 6 Part 2 - SCADA

27 Sep 2015

In this blog post, I will present and explain the remainder of the design and implementation of my vertical farming SCADA system.This post is focused on system data acquisition, utilization, and logging and will serve as an overview of the data to be collected and analyzed. I will cover many of these data points in more detail in subsequent blog posts. As this system has been developed as a prototype for research and development, I will be monitoring and logging many more data points than might be practical in a production installation. This will allow me to determine those data that are most critical to an optimum cultivation environment as well as reliable, robust and energy efficient system operation.

Just to reiterate...

So, what is SCADA?

SCADA (supervisory control and data acquisition) is a system operating with coded signals over communication channels so as to provide control of remote equipment (using typically one communication channel per remote station). The control system may be combined with a data acquisition system by adding the use of coded signals over communication channels to acquire data about the status of the remote equipment. This data can then be used as control feedback, for HMI display, and for system data logging.

Overview of data to be monitored and logged and how it will be utilized in the system.

Table 1 defines the cultivation area data points to be monitored and logged.

Data Point	Sensor	Output	Unit Measure	Status	Function
Cultivation Data
Ambient Temperature	SiLabs Sensor-Puck	Analog	Degrees Centigrade	Implemented	Monitor cultivation area temperature. Possible feedback for cultivation area automatic environmental control. For analysis of optimal cultivation temperature.
Relative Humidity	SiLabs Sensor-Puck	Analog	Percentage	Implemented	Monitor cultivation area humidity. Possible feedback for cultivation area automatic environmental control. For analysis of optimal cultivation humidity.
Ambient Light	SiLabs Sensor-Puck	Analog	Lux	Implemented	Monitor cultivation available light and verify supplemental lighting operation. For analysis of optimal cultivation lighting.
Ultra Violet Light	SiLabs Sensor-Puck	Analog	UV Index Value	Implemented	Monitor UV index of natural lighting. For analysis of optimal cultivation UV lighting.
Sensor-Puck Battery Level	SiLabs Sensor-Puck	Analog	V/mV	Implemented	Monitor Sensor-Puck battery usage and notification battery replacement required.
Nutrient Solution EC/TDS	Homemade sensor	Analog		Propsed	Monitor electrical conductivity/total dissolved solids of nutrient solution. Notification of nutrient replacement required. Feedback for operation of automatic nutrient replacement system. For analysis of optimal dissolved nutrient levels.
Nutrient Solution pH	Homemade sensor	Analog		Proposed	Monitor pH (acidity/alkalinity) of nutrient solution. Notification of pH adjustment. Feedback for operation of automatic pH adjustment system. For analysis of optimal pH levels
Grow Container Moisture Level	Sunkee Soil Hygrometer	Anaog/Digital	Above/Below Threshold Percentage of Moisture	Partialy Implemented	Monitor lowest level container of stacked container cultivation unit. Provide feedback for operation of automatic ebb and flow nutrient feed system.
Nutrient Reservoir Temperature	DS18B20 Waterproof temperature probe	Digital W/One Wire Interface	(9, 10, 11, or 12 bits) Binary value.	Partialy Implemented	Monitor nutrient solution reservoir temperature. Possible feedback for operation of reservoir heating/cooling system. For analysis of optimal nutrient solution temperature.
Cultivation System Operational Data
Cultivator Rotator Operational	???	Digital	Dry contact switch output	Proposed	Verify cultivator rotator system is operational. Notification of non-operational.
Nutrient Feed Timer Cycle Time	Timer hacked control line	Digital	Digital signal output	Implemented	Monitor nutrient feed cycle times and durations. Verify nutrient feed timer circuit is operational. Notification of non-operational.
Nutrient Feed Pump Operational	???	Digital	Dry contact switch output	Proposed	Verify nutrient feed pump is operational. Notification of non-operational.
EZR32WG Operating Temperature	Controller Board Si7021	Analog	Degrees Centigrade	Implemented	Monitor MCU operating environment temperature. Possible feedback for automatic system environmental control.
EZR32WG Relative Humidity	Controller Board Si7021	Analog	Percentage	Implemented	Monitor MCU operating environment humidity. Possible feedback for automatic system environmental control.
EZR32WG Current usage	Controller Board AEM	Analog	uA/mA	Partialy Implemented	Monitor MCU current usage. Feedback for low energy operation and for estimating total MCU energy usage.
Rpi Core Temperature	Onboard temp sensor	Analog	Degrees Centigrade	Implemented	Monitor Raspberry Pi core operating temperature. Possible feedback for automatic system environmental control.
Rpi Memory Usage	Linux System data	Analog	Kb	Implemented	Monitor Raspberry Pi memory usage. Analysis for code optimization. Notification of possible memory leaks.
RPi Processor Usage	Linux System data	Analog	Percentage	Implemented	Monitor Raspberry Pi memory usage. Analysis for code optimization. Notification of processor over usage, possible runaway threading, etc...
Total system current usage	Hall Effect Current Sensor	Analog	A/mA	Proposed	Monitor total cultivation system current usage. For calculating and recording total cultivation system energy usage.

Table 1.

Table 2 defines the centralized control area data points to be monitored and logged.

Data Point	Sensor	Output	Unit Measure	Status	Function
Central Control System Operational Data
EZR32WG Operating Temperature	Controller Board Si7021	Analog	Degrees Centigrade	Implemented	Monitor MCU operating environment temperature. Possible feedback for automatic system environmental control.
EZR32WG Relative Humidity	Controller Board Si7021	Analog	Percentage	Implemented	Monitor MCU operating environment humidity. Possible feedback for automatic system environmental control.
EZR32WG Current usage	Controller Board AEM	Analog	uA/mA	Partialy Implemented	Monitor MCU current usage. Feedback for low energy operation and for estimating total MCU energy usage.
Rpi Core Temperature	Linux System data	Analog	Degrees Centigrade	Implemented	Monitor Raspberry Pi core operating temperature. Possible feedback for automatic system environmental control.
Rpi Memory Usage	Linux System data	Analog	Kb	Implemented	Monitor Raspberry Pi memory usage. Analysis for code optimization. Notification of possible memory leaks.
RPi Processor Usage	Linux System data	Analog	Percentage	Implemented	Monitor Raspberry Pi memory usage. Analysis for code optimization. Notification of processor over usage, possible runaway threading, etc...
Total system current usage	Hall Effect Current Sensor	Analog	A/mA	Proposed	Monitor total cultivation system current usage. For calculating and recording total cultivation system energy usage.

Table 2.

Wow, that's a lot of data points. But for an R&D based prototype that's just what I would expect to see. As testing moves forward I suspect some of these data points will be relevant, and collected only if there is an issue that needs to be resolved and others will be abandoned altogether. But for now I'll watch and try to analyze all of them.

Again, in subsequent blog posts, I will cover many of these data points, the sensors used to collect the data and how they will be analyzed and used as feedback for control.

Good luck to all the challengers and happy vertical farming!

Cheers,

Rick