A machine with nobody in the seat has no face. STE SIGNAL is designed to give it one.
It is designed to show what the machine is doing. It never shows permission to walk up.
A crew reads an operator without thinking about it: where they are looking, whether they have seen you, which way the house is about to come round. Take the operator out of the seat and all of that goes with them. It is designed to put it back where a crew can read it from where they stand: a light tower on the machine, an audible warning with distinct signatures, and an indicator that shows which way the swing is coming.
What it is designed to do, and where it stops.
Both lists are set at the same size, because the second one is what keeps a crew where they belong.
- The tower. Which state the machine is in: faulted, deliberately holding, or working, read from any side. One state, one appearance, every time.
- The sound. A fault does not sound like a deliberate stop, and a deliberate stop does not sound like a machine about to move. A crew learns three sounds, not a language.
- The swing. Which way the upper structure is coming round: the one thing a person on the ground most needs and most often has to guess.
- No permission. There is no signal on it that means walk up, and that absence is deliberate.
- No protection. It carries information, and nothing on it is designed to stop a machine.
- No stand-in for a person. An operator's judgement, a spotter and the site's own traffic rules stay where they were.
One state, one appearance, and red is only ever a fault.
White while the unit is working. Red kept for a fault, steady and never flashing. Amber for a machine that has been asked to stand down, so a machine stopped on purpose never looks like a machine that has broken. Every lamp is designed to report back, so a failed lamp is a known state instead of a silent gap, and the colours are chosen against Alberta's vehicle lighting rules.
Every machine state maps to exactly one appearance and one sound, settled in advance rather than by whoever fits it on the day. A fault is designed to look like a fault until a person says otherwise.
Why there is no green light.
Every instinct in signage says put a green light on it. We did not, and we will not. A green light is read as permission, and this is not a device that can give it. It is designed to report what the machine is doing. It cannot know where you are standing or what the machine is about to be asked to do.
Our own rules are explicit: something that senses a site may take permission away and never grant it. So the tower reports the state, and the decision to walk up stays with the people and the procedures that owned it before we arrived. It reports; it does not decide, and nothing on it is designed to be set by hand to say something the machine is not doing.
One of five, and the five are designed as one set.
What stops a machine is the wired stop set on the machine. The five sit beside that rather than in place of it, and are designed to agree with each other instead of each solving its own corner. All five are set out here.
A handheld a person carries that asks a machine to stand down.
A request, never an emergency stop. Amber is what tells a site that the machine was asked, rather than that it broke.
STE Approach Intrusion SensingA zone around the machine that the machine watches for itself.
Designed to be safety-grade, and described as designed until it is assessed. It is the one of the five designed to be safety-grade.
STE CABA device in the other machine's cab, so the driver knows what our machine is doing.
The driver backing in to load out keeps every decision. The unit never authorizes an approach or a departure.
STE SISThe paperwork that makes a machine a member of the crew.
A unit files; a person accepts by typing their name.
Where this stands.
STE SIGNAL is designed, specified and written down in full: the tower, the mapping from every machine state to one appearance and one sound, the audible signatures, the swing-direction indicator, the hazards it answers and the checks that would close each one. That design is what we put in front of your safety people, and they may read all of it, including what we do not know. No assessment against ISO 13849 or ISO 17757, the standards we design against, has been performed. We would rather you read that here than find it out for yourself later. A person walks around the machine, completes the pre-start inspection, starts it and clears it for operation. Only then does Eddie engage the controls: every session, every machine, no exceptions. Eddie never starts, wakes or inspects a machine. We claim the design and nothing past it. Your machine's warranty, its conformity and your liability position are for your counsel.
For the crew and the people who can say no.
No, and there never will be. The tower reports what the machine is doing. It does not know where you are standing or what is behind the machine, so it cannot give permission. The decision to walk up stays with your people and your procedures.
It is advisory and says so. It shows what the machine is doing; it stops nothing.