Start with the operating requirement
A red-green light must be tied to a documented state machine rather than a single assumed barrier relay. 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 |
|---|---|---|
| Equipment states | Closed, opening, open, closing, stopped and fault | Defines the source of each indication |
| Commands | Open, close, hold and authorized override | Separates request from confirmed state |
| Feedback | Limit switches, controller status and vehicle detection | Shows how state is verified |
| Indications | Red, green, flashing or blank under each state | Builds the signal truth table |
| Fault handling | Contradictory feedback, timeout, lost power and recovery | Defines abnormal operation |
Use a controlled review sequence
- Equipment states: Closed, opening, open, closing, stopped and fault Defines the source of each indication
- Commands: Open, close, hold and authorized override Separates request from confirmed state
- Feedback: Limit switches, controller status and vehicle detection Shows how state is verified
- Indications: Red, green, flashing or blank under each state Builds the signal truth table
- Fault handling: Contradictory feedback, timeout, lost power and recovery Defines abnormal operation
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
- Showing green from an open command instead of confirmed state
- Omitting manual operation and maintenance modes
- Connecting loads without checking relay and supply ratings
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
Can a traffic light connect directly to a gate limit switch?
Only after the electrical ratings, isolation and required logic are reviewed. An interface relay or controller may be needed.
What should green mean?
The operator must define it clearly, commonly from verified permission and equipment state rather than a command alone.
What documents belong in the order?
Provide the state table, I/O list, wiring diagram, voltage, mounting and abnormal-state acceptance tests.