Start with the operating problem.
Then define the control system.

Provide motor nameplate data, load type, speed range, overload duty, supply system, control signals, communication, braking or bypass needs, cable length, ambient conditions, destination and required documents. Panel dimensions alone cannot define a safe drive system.

Send the functional description, I/O list, instrument and motor list, supply data, operating modes, interlocks, HMI requirements, network topology, third-party interfaces, environment and FAT expectations. If any input is missing, the quotation should state the assumption.

Yes, after a release review. The review should resolve incomplete article numbers, incompatible components, missing protection or accessories, drawing conflicts, standards basis, customer-supplied software and the required inspection record before assembly starts.

Choose a VFD panel when the process needs speed control or advanced drive functions. Choose a starter panel for fixed-speed motors where direct, reversing, star-delta or soft starting meets the duty. Motor torque, starting current, mechanical stress and process control decide the architecture.

They can share an enclosure when segregation, heat loss, EMC, service access, cable routing and destination rules are properly addressed. Higher power, harsh environments or maintainability requirements may favor separated sections or cabinets.

Plan a retrofit when lifecycle risk, unavailable backups, recurring failures, incompatible additions or long production exposure make reactive replacement unreliable. The decision should include installed-base data, software access, cutover time, rollback and acceptance testing.

A typical agreed FAT reviews drawings and BOM, workmanship and labels, protective conductor continuity, control power, I/O simulation, interlocks, alarms, HMI navigation, available network functions and drive or starter settings. It does not prove the actual site load or field installation.

Only when the applicable standard, design responsibilities, verification methods, manufacturing controls and documentation are explicitly agreed and supported. Mentioning IEC 60204-1 or IEC 61439 is not itself evidence of compliance or third-party certification.

FAT checks the agreed panel functions in the workshop using available simulations. Site testing confirms field wiring, real motors and instruments, plant networks, process behavior and integration under actual conditions. The two scopes should be documented separately.

The agreed supply may include the assembled cabinet, approved components, internal wiring and labels, released drawings, parameter records, FAT evidence, packing protection and listed export documents. Field cables, site commissioning and local certification are separate unless stated.

Responsibility must be written into the scope. It should state who supplies source projects, licenses and passwords; who writes or converts code; which devices are available for test; and who owns commissioning changes and final backups.

Approve a design basis, BOM and drawings before production; define change control, witness points, FAT cases, document formats, packing and acceptance responsibilities; and keep a single technical issue list. Price comparison is meaningful only when these scopes are aligned.