A note from Rusty Crawford of Accutime Timing Systems on Stage Lock

Stage Lock has been around for a while in different designs by different timing system manufacturers. With Accutime’s Stage Lock, when the tree is coming down, if the Stage Lock sensor detects that the car has rolled backward, and not forward, a small amount (less than an inch), the start time for this car does not trigger until the car rolls forward and the race starts normally on the back side of the front tire. If during the sequence, the car happens to roll back too far, you will red light upon activation of the tree. The stage lights on the tree continue to reflect the position of the tire, whether it is in or out of the stage beam, at all times. The stage light on the tree is not locked. This allows the racer to understand their position and the race timing is preserved, ie, it will start from the right spot every run. When the tree starts coming down, it is a drag race! Be ready to leave on time!



A point of perspective – the old movies flashed pictures at 30 frames a second (30 Hz). At this rate you would not see the stage light flicker, just like you cannot see the old movies change. The starting line beams are a couple orders of magnitude faster. It is a track choice to choose stage lock as an option, along with worst red, blind cross and more. The software and hardware are available to all of our tracks and many are running stage lock regularly. The difference between a red light or not can be less than the thickness of a credit card.



Accutime’s Worst Red (an equivalent function to TruStart®) was designed and implemented independently. The hardware and software is unique to Accutime. Our worst red feature has worked flawlessly with any and all of our other features including stage lock.


Russell Crawford
Accutime Timing Systems LLC

How far from the stage receptor to the
Stage Lock receptor? Does the Stage Lock beam run at an angle?

Does the tree act differently between timing system makers?

Phill,

look at the previous page as someone posted a picture of the additional sensors. The pic shows a Rt lane setup. Stage lock sensors are only needed in the middle starting line setup. The stage lock sensors are a little over 2 inches back from the stage sensor and they are not on an angle.

Thats too general of a question on does the tree act differently. Be more specific as stage lock performs the same function between timing systems of locking the stage signal in place. But there are alot of variables in play.

This is where alot of questions and confusion comes in. With SL turned on, its to prevent the legit red light because your car shook/ vibrated/ or moved ever so slightly backwards ( usually when transbrake is applied. Think causality, if your car moved backwards in the very small window say 1.5 inches its going to throw off your downtrack number. the answer is possibly because now you are getting a tiny rolling start on the forward motion of breaking the stage beam to officially start the downtrack timers and more obvious will be a late reaction time and you are now say an inch back from the actual stage beam. Keep in mind if you backup More that the 2.xx inches stage lock allows you will get a red light.

There is a Visual difference on the tree between accutime and compulink with stage lock.

Compulink keeps the stage light on the tree locked on with SL turned on, unless you back up too far then it goes red.

Accutime, with SL turned on and your car moves back far enough the stage light will go off. Again you move backwards out of the 2.xx window and it will go red.

Its a difference of philosophy between timing systems. I prefer the accutime way better from a track ops perspective, if its being recorded you will see the stage light go out if the car moves back far enough. Thus eliminates the well my car never moved and i have a whacked out RT. And secondly its a drivers aid if you know your car moves on the starting line for whatever reason and you see the stage light go off it now lets your brain know i need to race the finish line different as you have to make up for late reaction. Basically lets you know where you are at on the starting line.

Is Stage lock a help, yes for sure for cars dragsters that move ever so slightly on the starting. prevents the dreaded -5000 on your timeslip. But with everything good there is potential of side effects. If your car moves back an in inch or so you can figure it out that your not in the same spot on the starting line as a previous run and numbers will be different.

So to understand it stage lock, locks the timing system but not where your car is actually at inside that SL 2.xx range.

/\ Interesting read, its always a good day when you learn something.

Turk, the diagram is what caused me to ask if the beam was at an angle. Does any timing system notify on the timeslip when stage lock was used?

Yes the stage loc beam is at an angle. Actually their is NO beam, it's a flood of light with a receiver. Have fun with that. Beam tracking, bleed over, etc. When maintenance properly, no problems, and like anything else, without maintenance you get it. Literally.

With Accutime I'm not 100% but Rusty has the fix by the system shutting off once the pre stage bulb is off making it a non issue.

Compulink I'm 100% it's at an angle and does NOT shut off when the prestage bulb goes off. It has to see light just like the stage receiver.

This message has been edited. Last edited by: DragRaceResults,

So, Accutime stage bulb can still flicker but with Compulink it can't?

Phil on any Accutime system, the bottom of every timeslip has all the info you are looking for.

IF you see SL - stage lock
if you see WR - worst red
and others

then all the tree autostart settings .6 - 1.0 - 10

Some tracks my very on the above settings.

If a track is using the Etimeslip i believe this info gets cut off..

As for the bulb flicker i explain that under a different post.

Turk, can SL be turned on/off in just one lane?

Stagelock is a class setting and can not be turned off by lane. Not sure why someone would want it turned off by lane.

Is there SL in footbrake? No box?

Phil - stage loc is an option that can be turned on or off in any class / category. It is always the option of the track / promoter as to whether they want to use it or not if their current software system and hardware are configured for it.

I was wondering if stage lock could be turned off like crosstalk.