Short answer: a greenhouse automation system connects measured conditions to equipment through a written control sequence. Sensors, a controller, actuators, alarms, manual overrides and commissioning records all belong to the system. A dashboard alone does not automate a greenhouse, and adding sensors cannot correct undersized heating, cooling, ventilation or irrigation equipment.
Define the control job before choosing hardware
Start with the crop and operating plan. Record the crop, growth stage, production calendar and acceptable temperature, humidity, light, root-zone and carbon dioxide ranges. State which conditions are targets and which are alarm limits. The control designer then translates those requirements into equipment stages and priorities.
The University of Florida's environmental computer guidance separates measured variables, system state and control decisions. That distinction matters in procurement. An air-temperature sensor reports a condition. It does not prove that a vent opened, a fan delivered its design airflow or a valve supplied the requested water.
Map inputs, decisions and outputs
| Layer | Items to define | Acceptance evidence |
|---|---|---|
| Inputs | Crop-zone temperature and humidity, outside weather, light, carbon dioxide, water pressure, flow, tank level and equipment feedback | Sensor model, range, accuracy, location, shield, calibration and failure value |
| Control logic | Setpoints, deadbands, delays, stages, priorities, inhibit conditions and seasonal modes | Readable control narrative and tested sequence for every operating mode |
| Outputs | Vents, curtains, fans, pads, fog, heat, irrigation, dosing, lighting and carbon dioxide equipment | I/O schedule, electrical interface, command feedback and manual override |
| Protection | High and low limits, wind and rain interlocks, motor trips, empty tanks, sensor faults and power loss | Alarm list, safe state, notification route, response time and backup action |
| Records | Sensor values, commands, equipment feedback, alarms, user changes and maintenance events | Data interval, retention, export format, time synchronization and access roles |
Place sensors where the crop experiences the air
Temperature and humidity sensors should represent the crop zone, not the roof space or a sunny wall. Shield them from direct radiation and keep them away from heaters, doors, wet pads and air jets unless the point is intentionally measuring that zone. Large houses need enough locations to reveal differences between inlets, the middle of the crop and exhaust areas.
Define calibration checks and a replacement process. A control system can make consistent decisions from a biased sensor and still damage the crop. The acceptance test should compare installed readings with a reference instrument and confirm how the controller reacts when a signal is missing or implausible.
Write equipment priorities and interlocks
Heating, vents, exhaust fans, evaporative cooling, screens and carbon dioxide dosing can work against one another if the sequence is vague. State which stage starts first, the condition that starts it, the delay before the next stage and the condition that stops it. Include minimum run times where short cycling could damage equipment.
UF/IFAS fan-and-pad guidance warns against simultaneous heating and cooling and recommends representative, shielded sensing at plant level. The same principle applies to a computer controller. Software does not remove the need for correct airflow, sensor placement and equipment capacity.
Choose a safe state for every credible fault
- Specify the response to loss of grid power, controller power and communications.
- Define what happens if an inside or outside sensor fails or disagrees with a second sensor.
- Use equipment feedback where a command without movement could expose the crop.
- State wind, rain, freeze and fire actions for vents, screens and heating equipment.
- Provide local manual controls that remain usable during a network outage.
- Assign alarm recipients, escalation time and the operator action for each alarm.
Commission the sequence with real equipment
Factory configuration is not site commissioning. Test every input and output after installation. Run the normal day, night, heat, cooling, irrigation and storm modes. Then simulate sensor faults, a tripped motor, a failed pump, a stuck vent, network loss and backup power operation.
Record the result beside the control narrative. The owner should receive the final I/O list, drawings, setpoints, alarm list, user accounts, backups, software version, spare parts and training record. Any remote service connection needs named access, a revocation process and an offline recovery method.
Information to send with an automation RFQ
- Crop, growth stages, production calendar and environmental limits.
- Greenhouse zones, dimensions, covering, screens and equipment layout.
- Heating, ventilation, cooling, irrigation, dosing and lighting capacities.
- Required sensors, measurement locations, accuracy and calibration process.
- Control modes, stages, interlocks, alarms and safe states.
- Electrical supply, network, backup power and local manual controls.
- Data retention, export, user roles, remote access and service ownership.
- Commissioning tests, training, documentation, spares and response expectations.
Related CFGET planning pages
Use the greenhouse intelligent control system overview to identify available equipment interfaces. The climate-controlled greenhouse planning guide defines the wider heating and cooling scope, while the commercial project planning guide covers site and responsibility inputs.
Technical references
- University of Florida IFAS: Basic concepts in environmental computer control
- University of Florida IFAS: Fan and pad greenhouse cooling systems and controls
- University of Alaska Fairbanks Extension: Controlling the greenhouse environment
Preparing a greenhouse controls quotation? Send CFGET the crop limits, zone layout, equipment schedule, utilities and required fault tests. The returned scope should show the sequence, interfaces and acceptance evidence.