How do I set a limit from my own document?
Type the limit from your own document into the Limit box in the top bar, and the instrument shows the odds of crossing it, a dashed limit line and a GO, WATCH or STOP lamp.
ON THIS PAGE
Steps
Open the instrument and pick your persona first
Go to the /app page. If you use the persona menu in the top bar, choose it first: a persona overwrites the height, unit and limit. Only Spray (5 m/s) and Golf (8 mph) arrive with a limit; the rest start with the Limit box empty.
Tip: An empty Limit box means no limit, and the lamp reads NO LIMIT.
Find your limit in your own document
Consult your method statement, the manufacturer's manual or your permit, and find the wind speed value that applies to your task. Note the unit it is written in.
Tip: The instrument never supplies a limit of its own, and nor does the agent.
Choose the display unit
Use the Display unit menu at the right-hand end of the top bar to pick m/s, mph, kt or km/h, ideally the unit your document uses, so what you type matches what you read.
Tip: Switching unit later does not change the limit. It is shown in the new unit.
Enter the limit
Click the Limit box in the top bar (hint set limit while empty), type your number and press Enter or click away. The plus and minus buttons also work; from empty, the first press starts at the current wind rounded up, or 10 if unknown. Steps are 1, or 0.5 in m/s.
Tip: Clearing the box and committing it removes the limit.
Check what changed
With a limit set, the readout shows P(>limit), the exceedance fan draws a dashed line at your limit, the lamp shows GO, WATCH or STOP in words, and the time strip turns ember where the odds reach 40% or more.
Tip: Your limit is remembered on this device for next time.
01Why the instrument holds no limits of its own
The instrument contains no pre-set limits. It cannot tell you if it is fine to lift, spray or fly. Your limit depends on your equipment, task and site, and comes from your own documents, such as a manufacturer's manual, method statement or permit. The instrument reports the forecast and the probability of crossing the limit you provide. The decision to proceed stays with the competent person on site. The Spray and Golf personas start with ordinary defaults, so replace those with your own number.
02Gust or mean speed: which metric
There is no gust or mean switch next to the Limit box, or anywhere on the instrument page. The instrument picks the metric from your persona and height. Crane, Drone, Marine, Motorsport and Event compare gust, but only at exactly 10 m. At any other height, and for Spray, Golf and Wind ops, it compares the mean speed at your height, because the models give no gust above 10 m. If your document names one metric, check which is in use before relying on the lamp. The explicit choice of Gust or Mean speed is made in the rule editor on a saved site.
03Units and conversion
The Display unit menu offers m/s, mph, kt and km/h. Whatever you type is read in the unit shown, and stored in mph. If your document says 10 m/s, choose m/s and type 10. The Limit box accepts 0 to 130 in mph, kt and km/h, in whole steps, and 0 to 60 in m/s, in half steps. A value outside that range is pulled back to the nearest end. Changing the unit afterwards only changes how the limit is shown. Choose your persona and units explains the presets.
04Where the limit shows up
Once a limit is set, the readout shows P(>limit), the share of ensemble members at or above it for the hour, and adds EXCEED at 40% or more. The exceedance fan draws your limit as a dashed line. The lamp changes from NO LIMIT to GO, WATCH or STOP, each with its own shape and word. A next-exceed line names the next hour over or under 40%, and the time strip marks hours at 40% or more in ember. Route and Golf modes use the same limit. Reading the exceedance fan explains the chart.
05Saving the limit to a site as a rule
The Limit box is a working value on this device. To keep a limit with a saved site, sign in, save the site, then open the Alerts page and choose Set a rule, New rule or the pencil beside a site. The rule editor offers Metric, Breach when, Threshold, Asset height, Label and Source document, plus an email option. On Ops, the Fleet board has the same pencil. Alert rules are checked against the 10 m forecast, not the height-matched value. Arm an alert rule has the full steps.
06What to do when your document gives a range
If your document gives a band rather than a single number, the lower figure is the cautious one to enter. If it says to stop work between 10 and 12 m/s, you might enter 10 m/s so the lamp warns you at the earliest point. That is your call and should follow your own procedure.
Questions
Why does the instrument not have pre-set limits?
Operational limits vary with equipment, task and site, so one built-in number would be wrong for most people. Your limit comes from your own document. The instrument provides the forecast and the odds of crossing the limit you set, and the decision to proceed is always yours.
Can I set a different limit for different heights?
There is one Limit box and one value at a time. You choose the working height with the Height stepper, and the limit is compared with the wind at that height. If your document gives different limits at different heights, change the limit when you change the height. Set your working height explains how height is handled.
What happens if I enter an invalid limit?
The Limit box shows no error message. Text that is not a number is dropped and the box returns to its previous value, and a number outside the range is pulled to the nearest end. An empty box removes the limit. The message Enter your threshold from the governing document belongs to the rule editor, which rejects a threshold that is missing or zero.
How is the probability of exceeding my limit calculated?
P(>limit) is the fraction of ensemble members, from three ensemble systems, at or above your limit for the hour. If 10 of 40 members are at or above it, you see 25%. It counts members rather than giving a calibrated probability, and shows how much the forecasts disagree about your limit. Read P(exceed) has more.
If I change my units, do I need to re-enter my limit?
No. The limit is stored in mph and the box shows the same limit in whichever unit you pick. Because the box rounds to whole numbers, or one decimal in m/s, the figure may differ slightly from what you typed, but the stored value does not change.