This year there were some unfortunate problems with the lap counting system. The interrogator, the device that detects when a car passes, started to become unreliable very late on Friday night. This was a vital component to the system and it had to be working. First thing next morning, we contacted Alf Grasso of Integrated Silicon Design, the makers of the interrogator, and he was able to come down from Adelaide straight away and supply us with another interrogator. Because this interrogator was new, it had to be configured for our system which took some time.
While he was on his way to Murray Bridge, the original interrogator started working properly so we left it going while the cards were being placed on cars to test it. In the meantime, we attempted to configure the new interrogator for our system. We were unable to do this by the time the race started, so we used the original interrogator when the race started.
This was working fine, but after about 10 laps one of the cars had an accident and the race was stopped while an ambulance was called. A short while later when the race was continued, the original interrogator started to fail again. We hooked up the new one and used it to record the passes from then on. Because we had still been unable to configure it by this time, the data it was sending to the computers was not in the same format as the other interrogator. We started recording this raw data as it was, capturing it to a file. In the meantime, Jason Curl, a lap counting team member, began coding a program that would read this data and convert it into a useful format. But because we were only able to record the car passes and not the times they passed, we could only determine how many laps each car had done, not when they had done them, it was impossible to integrate this with the database we would normally use.
Alf took the original interrogator back to his office in Adelaide, and took it apart to try to identify the problem. It turned out to be a small, inexpensive chip which he was able to replace. He returned to Murray Bridge and by 7:00pm we were back to using the proper system. Everything went smoothly from then on as far as data collection was concerned, and we were now able to produce reports as per usual.
However, we were still faced with the problem of combining the data collected by the second interrogator over the last 5 hours and the normal system which was now running. We produced a spreadsheet showing all of the cars and how many laps they had completed during that time period, which we posted outside the lap counting van, next to the hourly reports we were printing for each class. To find out how many laps a team had done in total, it was necessary to add the number of laps on the spreadsheet to the number of laps on the report. This worked well for a few hours, and then we found a way to convert an existing class report into a spreadsheet and combine this with the existing spreadsheet, which allowed us to add together the two lap counts. We then started posting these spreadsheets in place of the hourly reports, which saved people from having to manually add the two lap counts together.
By about 9:00 am it was becoming obvious that there were problems with the results that were recorded by the 2nd interrogator. We are not sure where these errors came from, but we know that they were differing significantly to the lap counts that some individual teams had made themselves. Lap counting co-ordinator Brian Lee attended a team managers meeting, and it was decided that these results would be discarded and only the results recorded by the normal system would be used (7:00pm onwards, plus about the first 10 laps of the race). This would still provide a fairly realistic representation of the whole race, as it would give every team a relatively equal disadvantage.
As a result of this decision, there are a few laps in each car report, around the 8-12 range that are incorrect. The time for one of them will be around 4.5 - 5 hours, which is approximately the time that the normal system was not operating (and hence there will be a very low speed for this lap). These laps should be ignored, and although they are used in calculating the average speed, in most cases they will not affect it by more than around 2% since most cars have done over 100 laps.
The lap counting team would like to express their sincerest apologies to all teams for the problems that have occurred, but please understand that they were beyond our control. The interrogator we were using has performed flawlessly for a number of years, and no problems showed up during testing in the week leading up to the race. We believe that the results posted here provide a fair and accurate representation of the whole race. Although there may be some frustration or disappointment among teams who believe they have been adversely affected by this, we have done the best we can to produce the fairest outcome to an unfortunate situation.
We would especially like to thank Alf Grasso of Integrated Silicon Design, as without his dedicated assistance we would have been unable to continue scoring the race electronically.
Peter Kelly
Lap counting team member