ILC Trigger & DAQ Issues - 1 ILC DAQ issues ILC DAQ issues By P. Le Dû [email protected].
DAQ Article
Transcript of DAQ Article
8/6/2019 DAQ Article
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Data Acquisition Systems for Track Day Use
Jefferson Raley
What can it do for me?
A DAQ isn’t the first tool you should buy, it is probably the third. First get a lap timer to drive consistency
and give immediate feedback. Then get a camera and study your sessions. Make sure that you’re using
really working the car through turns and hitting your turn-in, apex and track-out points within inches
every time. It takes most people 30-40 weekends to reach that point. Once you’re there a Data
Acquisition System ( DAQ) can be a big help to find those last fractions of a second. I find it very useful
for:
Testing the effect of different lines, such as
? Is it faster to go through Ricochet at full throttle, versus a confidence lift to settle the car? (no)? Is it faster to track out over the old track at TWS turns 3 and 9? (yes)
? Is the tight line through Horseshoe at MSR Clockwise really faster? (yes)
Identifying and testing the effect of techniques such as
? Trail braking – I bet you’re using it more than you think
? Where is threshold braking worthwhile?
? Can I go faster in certain turns with a little left foot brake?
Identifying general areas to work on
? Look for variance. In my case, apex and exit are always the same, but corner entry varies. That is
what I need to work on.
? Identify low cornering values, sometimes that means you can go faster. Sometimes it means the
road has bad camber or low grip. This is most useful when you’re driving a new track.
Making cool videos
? Many DAQs have the ability to overlay a data dashboard on the video. For those that don’t, you
can buy third party software at www.trackvision.net that allows you to do it
? You can see my sample videos by searching for “SORX7” on Google Video
What won’t it do for me?
The DAQ can’t tell you how fast a corner could be taken, or how late you can brake. It can only show you
how your performance compares to other data. If you never go through a sector in under 10 seconds,
there is no way for the DAQ to know that you could. Similarly, the DAQ can tell you that you’re
generating 1.2g of cornering force at the apex of a particular corner. But the DAQ doesn’t know whether
1.3g is possible.
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I also don’t find DAQs very useful for setting up my own car. Sure, it can tell me if the car is oversteering
or understeering. But I already know that because I was the one driving the car. However, it can tell you
if a change made the car faster through certain sectors. Some changes, especially firmer suspensions,
can feel faster to the driver when they are actually slower.
Which one should I buy?There are a few main types of DAQs.
? Legacy systems such as Stack, Race Logic, MoTec and Pi Research. These are used in professional
race cars and tend not to have any built-in sensors. Most of these can be used to drive LCD dash
displays. These are not ideal for a track day enthusiast.
? Real-time video overlay systems such as AIM’s DaVid, Stack’s Overlay Video Logger and the
Multiview 8000 XG. These systems cost thousands of dollars once you add on cameras,
recording devices and sensors. They are also not as good for analyzing data.
? GPS-Based DAQs such as the Race Techology DL-1, RacePak G2X and Traqmate. These have
integrated GPS receivers and accelerometers. They can easily be moved from car to car and aredesigned for analyzing performance in the paddock. As mentioned above, all can be used with
Trackvision to overlay data onto video. This article focuses on these DAQs.
Race Technology DL1
This is a very popular unit, and the one that I chose for my own track car. It records data to a Compact
Flash card for later analysis on your PC. As with all DAQs in this category, it contains dual accelerometers
to measure cornering, braking and accelerating forces. It also contains a GPS receiver for computing
speed and drawing track maps. The DL1 costs about $1150.
Inputs:
The unit accepts the following inputs:
? Three 12v analog inputs (brake on/off, etc)
? Four 5v analog inputs (TPS, oil temp, water temp, oil pressure, steering angle, etc)? Four frequency inputs (for ABS wheel speed sensors)
? RPM signal from your coil or ECU
You can capture data from your car’s existing sensors, or Race technology sells a wide array of sensors.
The most useful of these is a string pot for capturing steering inputs. I’ve connected most of these in my
car, and never use them. The built-in GPS and accelerometers are sufficient for most analysis.
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Software:
Software is the most important differentiator in DAQs. All of the units in this comparison have similar
features and capabilities. What matters most is how easily you can turn all of that data into useable
knowledge. Race Technology’s software analysis far ahead of the other products. Some of the useful
features are:
? Playback – this is like the “dot race” as baseball games. You can show multiple laps racing
around the track with G-force vector displays. This is extremely useful for seeing where you are
gaining and losing time on one lap versus another.
? Tabbed Layout – You can customize the screen layout, and save up to 10 different layouts for
the analysis you typically perform. I have layouts for playback, sector charts, sector values and
friction circle.
? Lap and sector comparison – By default the software shows everything in terms of laps and
sectors. This makes it easy to compare the 5 fastest times through a sector, and determine what
you did different each time.
? GG Circle – This is the standard friction circle that everyone has talked about since MarkDonohue showed us how to think about driving. It is very useful for diagnosing your use of trail
braking, among other things.
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Seriously, this is the reason I bought a DL1. I downloaded and tested the competitive software in
preparation for this article, and couldn’t believe how bad they are. That said, don’t expect the
intuitiveness or quality of a multi-billion dollar Microsoft product. This isn’t MS Office, and you will find
bugs and annoyances. You can download and test Race Technology’s analysis software at
http://www.race-technology.com/software_10_1095.html
Display
The biggest drawback of the DL1 is that it does not come with a dash display, so it can’t show you lap
times while you’re driving. This means you have to use a separate lap timer, or pay another $675 for
their Dash1 display.
Racepak G2X
This is a very complete system, and includes a very nice dash display at the lowest price in this
comparison. It records data to a Compact Flash card for later analysis on your PC. As with all DAQs in this
category, it contains dual accelerometers to measure cornering, braking and accelerating forces. It also
contains a GPS receiver for computing speed and drawing track maps. The G2X costs about $950.
Inputs:
One nice feature is that, for an additional $350, you can buy a module to connect the G2X directly to
several popular types of fuel injection computers, including Accel, Autronic, FAST and AEM. A majordrawback is that you have to buy one of their $119 Vnet modules for each sensor you add, or buy the
sensors from them.
Software:
The G2X uses a software program called DataLink. Some notable points are:
? Track mapping – As with all of these tools, the software use GPS information to draw an
accurate track map.
? GG Plot – The software has a standard selection for showing the friction circle, which makes it
easier to show this data than on the DL1, which requires some configuration.
? Interface – This is painfully cumbersome. While none of these tools are each to use, I simply
don’t see how you could get valuable knowledge out of this software. Really, I tried to think of
something nice to say. I failed.
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The analysis software is critically important to getting the most from your investment. I highly
recommend downloading and testing it for yourself, rather than simply relying on this article. You candownload it for free at http://www.g2xtreme.com/downloads.htm.
Display
As mentioned above, the G2X comes with the best display of any compared in this article. The dash can
be configured to show RPM, speed, lap time, lap counter, lap time difference, lateral G, longitudinal G or
values from external sensors. It also contains programmable shift lights. If you are looking for an
inexpensive dash display, the G2X is the best product. However, if you want to analyze your data in the
paddock, the G2X may not be optimal.
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Traqmate Complete
As with the Racepak G2X, the Traqmate comes with a dash mounted display. This is very useful while
you are on track, and eliminates the need for a separate lap time system. Unlike the other 2 systems,
Traqmate stores data internally. A USB cable is used to transfer the data from the display to your PC for
analysis. The Traqmate costs about $1000.
Inputs:
For an addition $129, you can buy the TraqData adaptor. This unit accepts the following inputs:
? Four 12v analog inputs (TPS, water temp, oil pressure, steering angle, etc)
? 2 Digital inputs (brake on/off, etc)
? RPM signal from your coil or ECU
These should provide enough inputs for all but the most extreme data loggers.
Software:The Traqmate uses a software program called TraqView. Some notable points are:
? Playback – As with the DL1, the software can show a “dot race” of your day. This is the default
mode for TraqView, and a very useful tool.
? GG Plot – The software automatically shows friction circles for each driver.
? Interface – This is the easiest software to use, and very professionally designed. However, it has
significantly less functionality that the DL1 analysis package.
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Unfortunately Traqmate no longer makes the software available for download and testing. However,
you can download the manual and access screenshots through their website.
Display
The Traqmate comes with an attractive and simple LCD display that can show lap time, compass, speed
(from GPS) or a clock (also from the GPD signal.) The display unit also provides memory for the system.
To download your data, simply plug the display into your PC.
Overall Recommendations
A DAQ can be a very useful tool for improving lap times. In the first year, I was able to reduce lap times
by a second every time I visited a track. However, the DAQ is most useful once you are trying to wring
the last fractions of a second from your lap times.
This article compared three different DAQs that are targeted for serious amateurs. The tools each have
different strengths and weaknesses. If in-depth data analysis is your goal, then the Race Technology DL1
will tend to be the best choice. If in-car timing and simplicity are more important, then the Traqmate is
an excellent tool. Finally, while the Racepak G2X has an excellent dash, the analysis software is simply
not strong enough to make it a serious DAQ solution.
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Feature Comparison Chart
MakeRace
Technology RacePak Traqmate
Model DL1 G2X Complete
Price $1150 $943 $1,000
Hardware
Display $675 Included IncludedSensor Ports 12 Unknown 7Cost to addsensors None
$119 persensor $129
Media Compact Flash Compact Flash Internal
GPS Yes Yes Yes
Accelerometers Two Two Two
Software
Playback Yes NA Yes
Tabbed Layout Yes NA N
Compare Laps Yes NA N
Friction Cicle Yes NA Yes
Usefullness Very High Low Moderate
Ease of Use Moderate Difficult Easy