RLS1 photocell alignment & reduced distances

If you are using the DIN plug to connect to the photocell, check to see if there is any corrosion on the plug. We switched to Banana plugs due to the fact that if you use any fertilizer/salt/urea on the race course it causes corrosion on the din plugs very fast and is a small contact area. Another option could be your meter may be out of whack and may need replacement if you were able to run a race with/out the meter fully in the green. Scary, but if you think your times were accurate, then this could be the case.

The Fred should be back in town by Thursday. He can give this a shot then. JK


Originally posted 20 Feb 2002 by Jim Karnes

Thanks for your input. I'm from Laurel Mountain in western PA. Our set-up is not permanent - we move the equipment around but we always have the S3 within 10-20 meters of the cells so you're right,I'm sure distance is not the issue. We pick up power from the S3 and connect via the DIN connector. I will double check that cable and connector to make sure it's transmitting the the 5V. If this is OK would changing to banana plugs really make any difference? I'm pretty sure we've had at least one race where we were able to starts and finishes without the needle on the cell being in the green. On that day we found alignment by simulating a start, aligning the cell and reflector until we got the audible "peep" and then locking things in at that position. On that day, the needle never did come into the green but we got what we believed to be accurate times. We're really due to upgrade to new equipment but budgets are tight and I don't see it happening this year. Trying to keep
this system running. If this reply gives you any other ideas, I'd appreciate a your input. Thanks.


Originally posted 19 Feb 2002 by Steve Jupena jupenasd@aol.com

Well, sounds old to me, but Fred can upgrade your cells to use banana plugs to go to the S3. Do you use power from the S3 or c cells in the Eye?

Here in Killington, our finish is 3000 ft from our S4, so distance is not a factor.

Getting them in the green is very important. If you can't get the meter in the green, then that is your problem.

Do not take it apart---you are only asking for trouble !!

"when we're in alignment and the needle on the photocell doesn't always swing into the green" this means you are not in alignment--either you are or you are not, nothing else.

Max distance for the RLS1 not RSL1 is 25 meters !!

PS What Area you from?



Originally posted 19 Feb 2002 by Chase chase@vara.org

Steve:

Fred is still in SLC, so I will take a shot at your questions because he may not have time to check the forum for another day or two.

As far as I know, there are no gain adjustments on that cell. The pots adjust the duration of the signal interruption necessary to trip the cell. In other words, for motor racing, where the cars may be going >300k, that gets turned down because the car may only interrupt the beam for a few 1/10,000 (the cell's jitter rate), and for ski
racing, where the speeds are more like <100k, it gets turned up so that - for example - blowing snow or blowing B-net won't give you spurious impulses.

Let me ask a dumb, low-tech question - have you tried a different reflector? Reflector sensitivity is measured in "X white paper reflectivity", and it makes a huge difference in photocell performance. Yours may be delaminating.

Most of the reflectors commonly available at auto stores are crappy, it helps to buy good ones. Good ones cost a whopping four bucks, but they are hard to find. Try a good electrical contractor supply store.

A few years ago, when I was doing TV graphics for NASCAR Winston Cup Pole Night, Ted Savage and I researched the whole reflectivity issue and found some really good reflectors to buy. We were forced to, because Charlotte Motor Speedway has huge runoff areas and some of our shots were close to 100 yards. We couldn't use a TX cell because there were no holes in the track outer wall in which to mount them. My only recourse was to glue reflectors to the base of the wall,
and then have someone roaming around in a golf cart who could zip out there and glue a new one onto the wall every time one of the NASCAR yahoos hit the wall at 320k and pulverized our reflector.



Originally posted 19 Feb by James Broder