Write the functional description before selecting any component
Start with a plain-language sequence of what the machine does: each state, what causes it to change, what it does on a fault, and what a human is allowed to override. One page, written so a controls engineer and a maintenance technician would read it the same way.
Almost every wasted purchase traces back to a skipped step here. If the fault behaviour is not described, someone will invent it at commissioning — usually by adding a component that should have been in the panel from the start.
List the inputs and outputs as a table, with owners
For each signal, record:
- What it is, where it comes from physically, and what it is referenced to.
- Voltage, current and signal type — including whether it is isolated from the machine frame.
- Whether the signal is safety-related, and if so who has decided that.
- The connector and cable that carries it, and who specifies them.
That table becomes the wiring list, the panel drawing and the purchase list at once. When the table is written in the week the mechanical design is frozen, orders go out with one revision. When it is written during assembly, every row added afterwards is a rework.
Decide the safety architecture before the drive selection
Which stops exist, who can trigger them, and what each one removes is a design decision with consequences for drives, brakes, guarding and interlocks. Fix it early, and the drive and motor purchasing follows cleanly. Leave it open, and the safety function gets bolted onto a drive chosen without the headroom the function needs.
State also what the machine does when power is lost: where the axes stop, what has to be held, and what a restart sequence looks like. Those answers belong on the functional page, not in the commissioning notes.
Plan the panel and the routing with physical constraints, not ideals
Prototype machinery is usually tighter on space than the production version will be, and that is where electrical work suffers: no room for terminals, cable that has to bend tighter than its rating, power supplies mounted against a heat source, sensors that cannot be replaced without removing a guard.
So decide, in the model rather than at the machine: where the panel sits and how its door opens, how much spare terminal and breaker space you deliberately leave, where every connector is reachable from, and which cables are field-made versus ordered to length. Leave a documented spare capacity in the panel and in the controller's inputs — prototypes always grow.
Treat documentation and test access as a deliverable
For a prototype the electrical documentation is what makes the second and third build cheap: the wiring list, the panel layout, the signal table, the program with its version recorded, and the fault codes with their meaning. Agree the format before the build, because retrofitting it onto a finished machine never happens.
Plan the test points at the same time. Probing a signal, forcing an output and watching a state change are how a prototype is debugged; leaving test access out is what turns a two-hour fault find into a day of dismantling. This is also where a testing partner earns their place: the same team that runs the product development and electrical checks needs the signal table to write test cases against your pass lines.
A practical order of work
In short: functional description, then signal table, then safety architecture, then panel and routing in the model, then documentation and test points, and only after those the component purchase list. Reordering that sequence is what most prototype budgets pay for twice.
If you want that scope reviewed before you order, send us the functional description and your draft signal list, together with what the machine has to do at power loss and who signs off the safety functions. We will come back with the panel and control architecture we would use, the items we would fix before purchase, and the tests we would run once the prototype is powered up.
Contact Shenzhen PowerDe Automation Precision Equipment Co., Ltd. — Email: sales@powerde.net · Phone: +86 13023198376 · Contact page
