Before changing greenhouse control logic, recipes or alarm settings, record the current version, explain the proposed change, identify affected equipment and agree how to reverse it. A successful download to a controller is only one part of acceptance; the operating sequence and alarm behavior must also be checked.
Separate routine operation from engineering changes
A crop recipe adjustment within an approved range can follow a grower's operating procedure. Changing a sensor scale, an interlock, a software version or a control sequence needs engineering review. Define these categories for the installed system so staff know when to stop and request approval.
Create one change record with an identifier. Include the reason, devices affected, current configuration, proposed values, approving person and planned operating window. Attach screenshots or exports that let another person reconstruct the decision.
Before anyone applies the change
| Check | Evidence to retain |
|---|---|
| Baseline | Versioned export of logic, recipes, alarms and relevant network settings |
| Recovery | Accessible backup, compatible tools and a documented restore method |
| Crop protection | Agreed manual operation and escalation arrangements |
| Test plan | Expected inputs, outputs, alarms and recovery behavior |
| Permission | Named approver and qualified person carrying out the work |
| Rollback | Specific stop conditions and the person who can order reversal |
Keep passwords in the approved credential system, not in a general change log. Confirm that licenses and engineering software will be available if the normal computer fails.
Test the change safely
Use an isolated test environment where practical. An alarm test should verify that the message reaches the intended recipient, not just that an icon appears on the controller. Tests involving motors, heaters or pumps require precautions against unintended operation.
After applying the change, record actual results against the agreed test steps. Check related sequences that might be affected. A revised irrigation schedule, for example, may interact with water storage availability and pump operation.
Close the record after handover
Export the accepted configuration and link it to the change identifier. Update operating instructions and tell the next shift what changed. Preserve the previous accepted version under the site's retention policy. Schedule a review if the change was temporary or depended on assumptions about weather or crop demand.
NIST's OT backup guidance recommends integrating backups with change management and testing recovery. The worksheet here applies that principle to greenhouse operations; it is not a certification of the control system.
Questions from operators
Can an urgent change skip documentation?
Use a short emergency record that captures the reason, approval and baseline before work where feasible. Complete the test and handover record as soon as the situation permits.
Who should approve a crop setting change?
Define approval according to risk and the site's operating roles. A supplier's remote access does not replace the owner's approval process.
Ask Chengfei Greenhouse for the supplied equipment's version records and interface documentation before planning changes that affect its controls.
Further reading
NIST: OT Backup Quick Start Guide. The checklists are proposed operating and procurement tools; project limits require qualified review.