Graham Rudd Posted November 21, 2001 Share Posted November 21, 2001 I've recently started adding a data logging feature to my TC program. The RL unit seems to stop reporting sensible data on any given channel, if that channel's values drop below a certain threshold. I was wondering if this is normal behaviour? Has anyone who has had a play with the software provided by RL (traclog.exe) noticed a similar thing? As an example, my RPM will be flat-lined until they are over ~1100. Just curious, I'm sure it's perfectly normal but I thought I'd better check. Incidently, here's an image for anyone interested in how its going, its the prototype logging window. http://websites.cable.ntl.com/~graham.rudd/datalog.jpg BTW, the crazy cyan trace is the control signal, exaggerated so I can easily check when the TC is cutting in. Thanks Graham Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted November 21, 2001 Share Posted November 21, 2001 Apart form the HUGE spikes, that looks very familiar. Slip nicely visible on your rear wheel, cant tell which one! Good response to cut on the rpm! The stock DAT has a rev limit of 2000rpm so nothing much to see anyway at low revs. At last a way to see my system functions on my USB only laptop. Looks good, keep up the brilliant work. Quote Link to comment Share on other sites More sharing options...
Doughie Posted November 21, 2001 Share Posted November 21, 2001 OK folks, i'm looking at the trace in the screen-shot and i've got a question here (with regds RL TC, not the app in dev !): when rear-wheel slip occurs over the threshold value at which injection-cut happens, WHY does this show as an RPM drop ? If you think about it, RL TC moderates the engine power by cutting one or more cylinders per engine cycle. That does not imply an RPM cut. It implies that there are simply *fewer* cylinders firing PER engine revolution. Hence i would not expect engine revs to drop like it shows on the trace as this implies that the car is actually *slowing down*. unless there was hard-cut i wouldn't really expect engine revs to drop. I might expect the rate at which engine RPM is climbing to slow or level off though. hmm. I'm probably wrong here, but i'd like someone to come back with a lucid explanation on this. (if poss!) Moving on, reading the RL TC manual, there are several bits of text that imply that below a certain wheel rpm, the ABS does not generate a reliable signal. Maybe that is why the default minimum road-speed before the RL TC will do anything is 14kmh. (=about 8mph). (I don't quite understand why this may be so as i think as for *braking* the ABS will need to keep sending clear data to the ABS ECU on how the front wheel RPM compares with rear wheel RPM). For example on page 57 of the RLTC manual, is a picture of the TRACLOG prog. in action, and has the following text : "The above screen shows that two of the sensors are being picked up earlier than the other two. This is due to the rear having more pick up points than the front. This is not a problem unless the two sensors that pick up later are not registering before 14kmh." Graham your enahanced app is shaping up nicely by the looks of things. My comments : 1) TRACLOG has in the lower half of the screen 5 values : the 4 wheel speeds, and the engine rpm. This is useful info. Will you app have this ? 2) TRACLOG has a vertical bar which is user-moveable so that you can read off the wheel speeds and engine RPM at that point of the trace. again, useful to see what happened at what road speed and engine rpm. 3) What is the maximum time period that your app (and TRACLOG for that matter) can handle ? If it is more than a minute or so then the scale will be sufficiently compressed to require, potentially, some sort of zoom function. any chance ? Or will the graph scroll left and right ? i'm happy to Beta-test it if you require it. cheers (Edited by Doughie at 8:51 pm on Nov. 21, 2001) Quote Link to comment Share on other sites More sharing options...
Adam W Posted November 21, 2001 Share Posted November 21, 2001 So if TC doesn't work below 8mph, how does that square with the launch control function? I thought that worked by holding the revs at a set point (4000rpm?) and then when you dump the clutch, it keeps the wheels right on the edge of spinning in the same way it does when you boot it in a corner (ie by cutting injectors). How does this work at launch if there is no data below 8mph? Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted November 21, 2001 Share Posted November 21, 2001 You do get some slip on launch, but the 14kph is not related to the car speed but the rotation of the wheels. Look at the vids of Martins car you see some slip before the system really kicks in. Quote Link to comment Share on other sites More sharing options...
Graham Rudd Posted November 21, 2001 Author Share Posted November 21, 2001 Hence i would not expect engine revs to drop like it shows on the trace as this implies that the car is actually *slowing down*. unless there was hard-cut i wouldn't really expect engine revs to drop. I might expect the rate at which engine RPM is climbing to slow or level off though. hmm. I'm probably wrong here, but i'd like someone to come back with a lucid explanation on this. (if poss!) Yep, it did reach hard cut, if you check the large cyan spikes out you can clearly see the three cut levels, the two huge spikes are hard cut. This little section of data was sampled by planting my foot to the floor coming of a roundabout on a damp road. Graham your enahanced app is shaping up nicely by the looks of things. My comments : 1) TRACLOG has in the lower half of the screen 5 values : the 4 wheel speeds, and the engine rpm. This is useful info. Will you app have this ? 2) TRACLOG has a vertical bar which is user-moveable so that you can read off the wheel speeds and engine RPM at that point of the trace. again, useful to see what happened at what road speed and engine rpm. 3) What is the maximum time period that your app (and TRACLOG for that matter) can handle ? If it is more than a minute or so then the scale will be sufficiently compressed to require, potentially, some sort of zoom function. any chance ? Or will the graph scroll left and right ? i'm happy to Beta-test it if you require it. 1) Yep, there is no problem at all giving the app this. 2) The window shown is the real time capture, the Analyse button on that screen will be used to open up a new window. This window will provide the functionality to zoom, scroll, analyse etc. the data that has been captured, or a file loaded from disk. 3) Maximum time is pretty much an open issue. Assuming a sampling rate of 50Hz, thats 18000 bytes per minute to monitor all 6 channels. So for an hours worth of sampling it would be just over 1Mb. So given this data... you decide. As soon as I'm happy it isn't going to crash anyone's laptop I'll be happy to let anyone who wishes beta test it. Cheers Graham Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted November 21, 2001 Share Posted November 21, 2001 This sounds fantastic, just what we need. Sign me up for that Graham, my test track awaits!!!! Stu I think it is the torque that is reduced, each cylinder cut reducing by 1/6th or approx 50ftlb on max torque. So less torque less slip. IMO Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted November 21, 2001 Share Posted November 21, 2001 Graham I have just look at your trace again, and a few questions spring to mind. You said the trace is off a roundabout, I hope that explains why I can see four wheels. Are you using the 48 pulse file? Do the wheel traces appear as one at steady straight line speed? Quote Link to comment Share on other sites More sharing options...
Branners Posted November 21, 2001 Share Posted November 21, 2001 I know its probably of no technical use, but any chance of having a real time display of which wheel is spinning on a top down picture of the car, ie if the left rear wheel is spinning then the left rear wheel on the top down picture turns red or something. As I say, its of no technical use, but could be nice and flashy.... JB Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted November 21, 2001 Share Posted November 21, 2001 I like your style John. How about adding a little engine that changes colour with rpm;) Quote Link to comment Share on other sites More sharing options...
Graham Rudd Posted November 21, 2001 Author Share Posted November 21, 2001 Quote: from Phil Wall on 9:54 pm on Nov. 21, 2001[br]Graham I have just look at your trace again, and a few questions spring to mind. You said the trace is off a roundabout, I hope that explains why I can see four wheels. Are you using the 48 pulse file? Do the wheel traces appear as one at steady straight line speed? Now you mention they don't, not quite anyway. I am using the the 48 pulses. Maybe this is be because I have different tyres and different wear on the front/back. I hope so anyway. Quote Link to comment Share on other sites More sharing options...
Phil Wall Posted November 21, 2001 Share Posted November 21, 2001 May be I need to take the rear ABS sensor off and check the teeth.!!! I will check after work (Edited by Phil Wall at 10:07 pm on Nov. 21, 2001) Quote Link to comment Share on other sites More sharing options...
Doughie Posted November 21, 2001 Share Posted November 21, 2001 Front tyres on stock 17's : 643mm Rear tyres on stock 17's : 636mm. Diamtere difference between brand new tyres and tyres bordering on illegal = 12mm. Phil - it's *just* a possibility that the Supra has a *different* number of ABs sensor teeth front to rear. do you reckon it's worth checking to make sure ? Graham - what front and rear wheel diameters have you got set up on your RL TC ? and what tyre sizes are you using ? Quote Link to comment Share on other sites More sharing options...
Graham Rudd Posted November 21, 2001 Author Share Posted November 21, 2001 Quote: from branners on 9:58 pm on Nov. 21, 2001[br]I know its probably of no technical use, but any chance of having a real time display of which wheel is spinning on a top down picture of the car, ie if the left rear wheel is spinning then the left rear wheel on the top down picture turns red or something. As I say, its of no technical use, but could be nice and flashy.... JB Provide me with a nice top down picture and I'll provide you with a personal copy with it on! Quote Link to comment Share on other sites More sharing options...
Branners Posted November 21, 2001 Share Posted November 21, 2001 Quote: from Phil Wall on 10:01 pm on Nov. 21, 2001[br]I like your style John. How about adding a little engine that changes colour with rpm;) and then we could have a large brown patch behind the car which gets larger the greater the level of slip between all the wheels...!! Could also show the injectors being cut as a top down on the engine.... JB Quote Link to comment Share on other sites More sharing options...
Graham Rudd Posted November 21, 2001 Author Share Posted November 21, 2001 Quote: from Doughie on 10:08 pm on Nov. 21, 2001[br]Front Graham - what front and rear wheel diameters have you got set up on your RL TC ? and what tyre sizes are you using ? I have 285/30 18" rear, 245/45 18" front. I'm using width*aspect*2+rim diameter for the sizes, I don't have manufacturer's data. Quote Link to comment Share on other sites More sharing options...
Doughie Posted November 21, 2001 Share Posted November 21, 2001 that's the calculation i used too to get my numbers for my 17" rims. In fact i have a "spare" 17" tyre off the rim, and measured the circumference and therefore calcualted the diamater and it was VERY close to my calculated value. Quote Link to comment Share on other sites More sharing options...
Graham Rudd Posted November 21, 2001 Author Share Posted November 21, 2001 Quote: from branners on 10:11 pm on Nov. 21, 2001[br]and then we could have a large brown patch behind the car which gets larger the greater the level of slip between all the wheels...!! Could also show the injectors being cut as a top down on the engine.... JB Ooo nice... I don't want you to provide me with the image for that one though! :shocked: Actually, what I DO want to do is buy a cheapo GPS with an RS232 port for ~100 quid. Then I'm going to incorporate the feature into the data logging to also plot a 2D map along with the data capture. Hmmm.. the more I think about it the more I wanna do it. Thats it, I'm ordering a GPS tomorrow. Quote Link to comment Share on other sites More sharing options...
Doughie Posted November 21, 2001 Share Posted November 21, 2001 hang on Graham. - i emailed Justin 2 days ago saying "i want a GPS - sort me a discount" and he sugeested (obviously) getting a group buy together. I ahve done some research into it. Looks like a Garmin Etrex or GPS12 or a Magellan unit. What's your preferred max. price ? I may post up a thread on GPS to see how much interest we can get. Quote Link to comment Share on other sites More sharing options...
Graham Rudd Posted November 21, 2001 Author Share Posted November 21, 2001 Well, my maximum price would be on a sliding scale of what features it has. Obviously the one critical thing it needs from my point of view is an RS232 interface. Quote Link to comment Share on other sites More sharing options...
Branners Posted November 21, 2001 Share Posted November 21, 2001 Dont forget Racelogic have done a lot of work on GPS data logging as well, and if they take your software on as the standard then they may well assist you with the GPS logging stuff, ie they might give you the GPS receivers on loan.... JB Quote Link to comment Share on other sites More sharing options...
Graham Rudd Posted November 21, 2001 Author Share Posted November 21, 2001 Quote: from branners on 10:41 pm on Nov. 21, 2001[br]Dont forget Racelogic have done a lot of work on GPS data logging as well, and if they take your software on as the standard then they may well assist you with the GPS logging stuff, ie they might give you the GPS receivers on loan.... JB To be honest I sent a copy of my software to RL a few weeks back. They indicated that they might be willing to buy it. I wrote back and said I wasn't doing it to make money, and (jokingly) if they really wanted to give me something for it then they could swap me for one of their products. After a couple of e-mails from them saying it looked good I heard nothing else. I take this to mean they must be doing their own in-house development and aren't interested in obtaining a copy anymore. Anyway, the point is I'm not really prepared to approach them to ask, given the above assumption then I don't want to be seen to be trying to push mine on them. I'm sure they'll come up with a better system than I have, I'm just proud mine has been used as a tool to provide us with some useful information in the mean time. Quote Link to comment Share on other sites More sharing options...
Doughie Posted November 21, 2001 Share Posted November 21, 2001 Graham Are you sure they're not just going to nick your code and save themselves some development costs ? cos that's theft (assuming you hjave intellectual copyright on your app or whatever). don't trust anyone when it comes to business and money. that's my advice. Quote Link to comment Share on other sites More sharing options...
Doughie Posted November 21, 2001 Share Posted November 21, 2001 Graham Are you sure they're not just going to nick your code and save themselves some development costs ? cos that's theft (assuming you hjave intellectual copyright on your app or whatever). don't trust anyone when it comes to business and money. that's my advice. Quote Link to comment Share on other sites More sharing options...
Branners Posted November 21, 2001 Share Posted November 21, 2001 I have heard that the new RL software has been expected for a LONG time, so Im not sure if they are developing it in house and just dont have the time or if they have outsourced it and are having problems with it. Seemed strange to me that they would be using a real mode DOS program when Win95 was released 6 years ago.... Tony Wright also has a GPS, I dont think he frequents this list but can probably be contacted to see if you can borrow his unit. Unless of course you prefer to have your own unit anyway. JB Quote Link to comment Share on other sites More sharing options...
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