1. Start from the IO list, not from the program
Before anyone opens the PLC editor or the HMI project, one document has to be frozen: the IO list, with every tag name, address, signal type and the device it belongs to. If the electrical drawing and the PLC tag database disagree, every later step wastes time on tracing wires that are actually correct. The same list becomes the address map for the HMI, so the two projects are built against one source rather than against two interpretations of it.
A practical rule is to make the list carry three extra columns that most draft versions omit: which team owns the tag, whether it is visible to operators on the HMI, and whether it is logged for history. That single table settles most disputes about who changes what.
2. Agree the tag model and alarm classes before screens are drawn
Integration fails most often at the naming layer. When the PLC stores pressure as an integer scaled by ten and the HMI expects a floating-point engineering value, every screen inherits that mismatch. Fix the data type, scaling and engineering unit for each analogue tag now, and write them into the same document as the IO list.
Alarms need the same treatment. Group them by what the operator is expected to do: stop the machine, adjust a setting, or call maintenance. An HMI that raises the same pop-up for a sensor fault and a genuine process interruption trains operators to dismiss the screen. Decide the severity levels, the wording, and whether an alarm needs acknowledgement, and pass that definition to whoever builds the PLC alarm bits and whoever builds the HMI alarm object.
3. Build the HMI against machine behaviour, not against menus
Once the address map is fixed, the screen set follows from the machine's states: manual, home, automatic, paused, fault, maintenance. Screens for each state should exist before wiring starts, so an operator can be asked to walk through them on a simulator and say where they get stuck. That review costs an hour and prevents weeks of screen rework during the machine's first production run.
Interlock logic belongs in the PLC, and the HMI should reflect it rather than duplicate it. If a guard-open condition is also handled in a screen script, the two versions will drift apart the first time someone edits one of them. The HMI shows the state and blocks the action; the PLC decides whether motion is permitted.
4. Commission in four passes, with a written exit for each
The schedule below is what a reasonable team commits to on site. It does not assume everything is finished before the machine is powered; it assumes each pass has an exit condition that both supplier and buyer sign.
| Pass | What is verified | Exit condition |
|---|---|---|
| Point-to-point | Every input and output against the IO list; HMI display matches PLC state | Signed IO list with no open discrepancies |
| Function | Sequences, interlocks, safety responses, alarm behaviour | Each documented sequence runs; each alarm behaves per its class |
| Process | Product or process quality, cycle time, recipe handling | Agreed run conditions reached with the customer's own material |
| Handover | Operator and maintenance training, documentation, spares, backup | Trained staff, current drawings, and a restorable program backup |
A team that tries to blend the function and process passes usually discovers the fault late, when a supplier's engineer has already left site. Keeping the passes separate also keeps the responsibility clear: pass one is about wiring and addresses, pass two about logic, pass three about the customer's product, pass four about who can run it without support.
5. Plan the equipment cleaning step into the shutdown window
Integration projects are scheduled around downtime, and the cleaning work that accompanies a shutdown is often left out of the plan until the line is already stopped. If oil, coolant residue or process dust has to come off the machine before commissioning can proceed, that task needs a method chosen in advance. On the fixed machines in PowerDe's cleaning equipment range, such as the PowerDe HW02 steam cleaner, the dry-steam mode is the one used where standing water must be avoided near electrical enclosures, and the wet-steam mode carries the heavier soil. Its published parameters include 220 V operation, 6 kW heating power and a stainless steel tank, so it fits a normal workshop supply rather than a special feed.
Two cautions belong in the plan. First, steam on or near an enclosure is a decision for the electrical owner, not the cleaning crew: isolate and cover what must not see moisture, and use the low-moisture mode. Second, cleaning is part of the shutdown scope and should appear on the same schedule as the integration passes, otherwise it becomes the reason pass one starts late.
6. Who does what, and what to hand over
One named person should own the address map, one the HMI look and interaction, and one the site schedule. That is the smallest team that avoids the situation where three people each assume someone else confirmed the scaling of a pressure tag. On the buyer's side, an operator and a maintenance technician should attend the function pass, not only the handover pass; they raise the objections that a finished program hides.
Handover is not complete until the PLC and HMI programs are backed up outside the controller, the as-built drawings match the real wiring, and a fault reference the maintenance team can read exists in their language. Shenzhen PowerDe Automation Precision Equipment lists equipment integration, customized configuration and technical support among its engineering services, which is the scope a buyer should ask to see priced explicitly rather than assumed.
A short checklist before the first power-on
- One frozen IO list with data types, scaling and units
- Alarm severity classes defined and applied in both projects
- Interlocks implemented in the PLC, mirrored in the HMI
- Four commissioning passes with signed exit conditions
- Cleaning method for the shutdown window selected in advance
- Program backups, as-built drawings and fault reference agreed as deliverables
None of these items require special tooling. They require that the data model is agreed once and written down once. A team that plans that far ahead spends its site time running the machine instead of arguing about whose tag list is current.
