Start with the operating requirement
Output quantity and electrical load are different constraints and both belong in the controller I/O schedule. Begin with the site, intended operation and authority requirements. Record assumptions beside the requested configuration so the supplier, integrator and installer are reviewing the same system. The article is a buyer's planning resource; final design, compliance and operating decisions remain project specific.
Information to define before quotation
| Field | What to record | Why it matters |
|---|---|---|
| Load identity | Signal head, arrow, pedestrian display or auxiliary device | Links the calculation to the field schedule |
| Supply | Nominal voltage, tolerance and frequency or DC range | Sets the electrical basis |
| Per-channel load | Steady current, power and inrush where relevant | Checks the switching channel |
| Grouping | Shared neutral, simultaneous states and cabinet distribution | Checks common conductors and protective devices |
| Margin and evidence | Project rule, datasheet and measured result | Makes assumptions reviewable |
Use a controlled review sequence
- Load identity: Signal head, arrow, pedestrian display or auxiliary device Links the calculation to the field schedule
- Supply: Nominal voltage, tolerance and frequency or DC range Sets the electrical basis
- Per-channel load: Steady current, power and inrush where relevant Checks the switching channel
- Grouping: Shared neutral, simultaneous states and cabinet distribution Checks common conductors and protective devices
- Margin and evidence: Project rule, datasheet and measured result Makes assumptions reviewable
Give every important item an owner and a document reference. Where a value comes from a drawing, tender, authority instruction or product datasheet, identify that source and revision. Mark unresolved items rather than filling gaps with a catalogue assumption.
Build acceptance around observable evidence
Translate the approved requirements into checks that an independent witness can repeat. State the test setup, equipment identity, initial condition, expected result, measured or observed result and any deviation. Keep photographs, data exports and signed records with the relevant model, firmware or drawing revision.
A passing result for one configuration does not automatically cover a different voltage, optical assembly, interface, battery, mounting arrangement or software release. Define which differences require a document review, sample approval or repeated test.
Common specification mistakes
- Multiplying head count by three without a phase/I/O map
- Using only rated watts and ignoring switching or inrush
- Assuming spare outputs automatically provide spare electrical capacity
These errors usually appear when a quotation is based on a short product name instead of a system description. A clear schedule and acceptance record reduce rework during sample approval, production and commissioning.
Prepare the supplier enquiry
Send the project location, intended use, quantity, destination, applicable tender or standard, required interfaces, operating conditions and requested documents. Ask the supplier to identify confirmed items, options and exceptions in writing. For GAOQIAO catalogue options, start from the relevant product category and request the current drawing and data for the exact offered model.
Frequently asked questions
Is a 44-output controller always more powerful than a 22-output controller?
No. Output count does not by itself define per-channel current, total cabinet load or supported switching hardware.
Which value should be used for LED signal heads?
Use the electrical data for the exact voltage and module configuration, including any relevant startup behavior.
How should the calculation be accepted?
Review the load schedule, protection and wiring, then verify the installed configuration with the approved commissioning procedure.