Introduction: A replacement signal project moves faster when the old intersection's voltage, control logic, mounting, and countdown behavior reach the factory before the OEM drawing is prepared.
Replacing signal heads at a live intersection is rarely a straight catalog order. The pole, cabinet, controller, and local drawing set already exist, and the new hardware has to fit all four before shipment. A first quotation often exposes site questions that remain unanswered. Collecting those answers first turns a vague inquiry into a buildable OEM drawing, a fixed sample configuration, and a batch plan that matches the intersections being upgraded.
Start with the site, not the product. A factory can open an OEM drawing conversation quickly once it has a condition sheet describing what is on the pole today: measured supply voltage at the controller cabinet, the phase arrangement, the existing signal head model and lens size, the mounting bracket or pole clamp spacing, the conduit entry point, and the way the old countdown unit behaved. Site photos from the front, the side, and the cabinet interior reduce back-and-forth. So does the local drawing format, even a scanned copy, because drawing conventions differ by market and the factory must produce a file your engineer and your client's reviewer can both read.
The 400mm RYG all-round signal with red-green countdown is specified for AC 185V-265V, 50/60Hz. The voltage that matters for a replacement, however, is the one measured at the controller cabinet under load. Old intersections often sit at the end of a long feeder, and the voltage at the service entrance may differ from what the signal head sees during a busy cycle. Control logic matters just as much. Some older countdown units follow the controller's phase timing directly, some learn the sequence from lamp pulses, and some use a separate trigger line. A photo of the existing signal head terminal block together with the controller output schedule gives the factory the information needed to define the replacement interface.
A 400mm all-round head with countdown measures 1520×600×140mm overall, with three 400mm lens apertures and a countdown column built into the same housing. That footprint has to match the existing bracket, visor clearance, and spacing between adjacent heads on the same arm. Upgrading from a smaller head changes the face area and the load the bracket and pole clamp must carry, which is a mechanical question. FHWA MUTCD Part 4 is a useful reference for how signal size, visibility, and mounting configuration are usually judged on a replacement project. Lay the new dimensions over the old bracket drawing before OEM discussion gets serious.
The process starts with the condition sheet. Your engineering contact receives the site conditions, existing drawings, and quantity plan, then returns a marked-up drawing showing lens layout, countdown digit layout, terminal arrangement, mounting points, and overall outline. The review covers whether the countdown column sits to the right or left of the three lenses, how the digits scale against the 400mm apertures, and how the cable entry lines up with the existing conduit. Every line on the drawing corresponds to something visible on the pole or inside the cabinet. Approval makes the project repeatable: once you sign off the drawing, that revision becomes the production reference for every unit in the batch, keeping intersection three identical to intersection one. DAYU OPTOTECH Traffic Solutions works from project drawings for OEM/ODM orders, and the approved revision carries through automated assembly and aging testing. Batch planning follows the intersection list: heads per approach, packing and labeling per intersection, and aging checks grouped by shipment for acceptance review. Lock optical and electrical performance into the same drawing package so the sample and the batch stay aligned. This model has a 30° viewing angle in all four directions, visibility ≥500m, full-lens power ≤19W per colour, and countdown power ≤10W for red and ≤12W for green. Low draw per head helps replacement cabinets sized for older equipment with limited spare circuit capacity on long cable runs. Those figures also help when a client's reviewer compares the new hardware against the old load calculation.
The first capability is engineering response. A factory that can read site conditions and return a marked drawing with questions attached is more useful on a replacement project than one that only quotes from a catalog. The second is optical consistency across the batch. A 400mm head with 204 LEDs per colour lens and 128 LEDs per countdown unit depends on LED binning and lens alignment holding steady unit after unit; a visible mismatch between two heads on the same approach becomes a client complaint. The third is environmental confidence. This model is rated IP53 with a PC plus die-cast aluminum housing and an operating range of -40°C to +80°C, built around multiple seals. Aging testing before shipment is part of checking assembled units before they leave the factory. The fourth is overseas project support: a clear drawing package and packing information for the shipment and acceptance review. Established LED traffic signal light manufacturers and traffic safety equipment suppliers compete on these capabilities more than on headline pricing, because a failed head at a live intersection costs more than the hardware. This model is specified to GB/14887-2011 and related standards. That standard provides optical and testing context for signal heads, and ITE standards describe LED vehicle signal module performance benchmarks. These references guide technical questions; confirm country-specific compliance requirements in writing for the destination before ordering.
Replacement work rewards preparation. Measure the voltage at the cabinet, photograph the old head and its terminal block, record the bracket and pole clamp dimensions, describe how the old countdown behaved, and send the local drawing format with the intersection list. With those inputs, an OEM conversation can move from a marked drawing to an approved revision to a batch plan, and the approved drawing keeps every intersection in the project consistent. Send your existing site conditions, drawing, target quantity, and destination market to confirm the OEM scope for the 400mm RYG all-round signal with countdown, and ask for the drawing package, sample arrangement, MOQ, and lead time in the same message.
A: Gather the measured supply voltage at the controller cabinet, the phase and control logic feeding the existing head, the old head model and lens size, the bracket or pole clamp spacing, the conduit entry position, whether the old unit had countdown and how it was driven, and the local drawing format. Site photos from the front, side, and cabinet interior plus the intersection list complete the package and let the factory return a marked drawing with fewer open points.
A: Send the controller output schedule and a photo of the existing signal head terminal block. That shows whether the old countdown followed phase timing directly, learned the sequence from lamp pulses, or used a separate trigger line. The drawing can then show the proposed wiring interface and where the red-green countdown column will sit relative to the 400mm apertures. Confirm the exact control protocol in writing for the project before the sample stage begins.
A: Engineering drawing response and revision control come first, because the approved drawing keeps every intersection identical. Then optical consistency across the batch, aging testing before shipment, environmental sealing built around multiple seals, and overseas project support for the drawing package and shipment information. Confirm MOQ, lead time, price, warranty, and country-specific compliance requirements in writing for your project.
GB/14887-2011 signal standard reference
FHWA MUTCD 11th Edition - Part 4: Highway Traffic Signals
ITS Standards - ITE-A Community of Transportation Professionals
400mm RYG LED All-Round with Countdown Timer Traffic Signal Light
