___  ___
|  \/  |
| .  . |
| |\/| |
| |  | |
\_|  |_/
        
        

         
|\     /|
( \   / )
 \ (_) / 
  \   /  
   ) (   
   | |   
   \_/   
         

 ##      
 ##      
 #####   
 ##  ##  
 ##  ##  
 ##  ##  
 #####   
         

  _     
 | |    
 | |    
 | |___ 
 |_____|
        

 __     __
 \ \   / /
  \ \ / / 
   \ V /  
    \_/   
          

IMPORTANT: enter the case-INsensitive alphabetic (no numbers) code AND WRITE SOME SHORT summary of changes (below) if you are saving changes. (not required for previewing changes). Wiki-spamming is not tolerated, will be removed, so it does NOT even show up in history. Spammers go away now.


Visit Preferences to set your user name
Summary of change:
'''VEMS uses the PS2 clock signal to receive 0/5V wheelspeed frequency signal.''' Became very popular recently. The PS2 firmware uses the PS2 port for keyboard, and launch-RPM is time-based (not wheelspeed). For wheelspeed input to work, the "non-PS2" firmware must be uploaded ( my_make.16x14/vems.hex ). See GenBoard/UnderDevelopment/FirmwareChanges around and after 1.1.53 Use recent VemsTune. '''Sensitive pin''' PS2 clock input is a direct CPU pin. It is very sensitive. Either static electricity or 12V will damage the main processor immediately. Customers are advised to request in the WebShop order note: * '''PS2 clock wheelspeed input on EC18/17''' (used to be 2nd WBO2 FET). ** This '''is standard since 2009-08-01 unless you request otherwise (in the order note)'''. ** someone have been using EC18/17 for sensor ground (easy COMM and additional input wiring) and using EC18/8 for the Speed Input. * 4k7 pullup to +5V * 4k7 and 5V1 zener protection on the processor pin * the last steps on MembersPage/GergelyLezsak/AssemblyThreePointFive show a practical layout of the zener and the pullup resistor. ** Excellent news. Anything to protect the ecu from damage saves us time and money! With the 5V1 zener it is less likely to damage it, and an open-collector HALL sensor or a VR signal and a simple NPN inverter (same as CamHALLInverter) can be used to drive the signal (LM1815 is not necessary for this, although that would work too). Care is still needed of course. ---- '''Wheelspeed data usage''' * logging wheelspeed to notebook, or SDcard * sending to AfreshTiny/AimDisplay for well-visible display * boostcontrol - gear dependent boost * '''launchcontrol - wheelspeed dependent rpm-limit''' ---- '''Launchcontrol''' The good old initial launch behaviour with retard and launch-enrichment is still there. But after reaching the first entry in an '''8 entry table (array)''', no retard, no enrichment: 2x8 bytes for '''wheelspeed => RPMlimit'''. Firmware uses interpolation for smooth transitions between table-points. RPMlimit is in 100 RPM unit. wheelspeed is the unit of your choice. Usually: * km/h * or mph * or any other. It really just depends on calibration The same table is time => RPMlimit for the PS2 firmware where wheelspeed is not available. Time is in 64 msec unit. The first and last bin in the table are somewhat special: * Before the first entry is reached, the good old one-value RPMlimit set in config is used and retard and enrichment is applied "Launch RPM vs Road Speed" screen: http://www.vems.hu/files/sensors/WheelSpeed/VEMSMTRevSpeed.gif Kevin's note: I have the table/curve in the MegaTune(works in Megatune but not tested on engine yet) You'll note in the main menu and the [http://www.vems.hu/files/sensors/WheelSpeed/MT_around_1.1.53_launchcontrol_wheelspeed_vemsv3ini.zip ini] that I have changed many of the titles and have organized the functions differently. Note: the '''"launch-active" flag''' in VemsTune only '''lights up when the RPM-limit is reached (not when the button is pressed - this can be confusing)'''. So if you want to test an analog input switchbutton, configure the ALS input to that pin to see that it lights up. ---- '''Temporary note''' - for .ini file tweakers. This section should be cleaned up when these are deployed in both MegaTune and VemsTune 2009-05-xx releases. Direct commands for page15 (launchcontrol wheelspeed=>launchRPMlimit) read/write are [] brackets. * Offset 0..7 are RPM (unit=100 RPM) * offset 8..15 is the wheelspeed (unit of your choice, depends on calibration) Check the mct dump to see if s[0]= and s[1]=... values are set as you expect. ---- '''REST OF THE PAGE IS BRAINSTORMING''' ---- '''Freq to voltage''' - could also be used [http://www.elfa.se/pdf/73/731/07312713.pdf LM2917] frequency to voltage converter to get wheelspeed info on the LCD and for logging. The app note even has a design almost ready for use Is anyone besides me interested in this? Is there any problem with this solution that I am missing? //Emil
Optional: Add document to category:
Wiki formatting: * is Bullet list ** Bullet list subentry ... '''Bold''', ---- is horizontal ruler, <code> preformatted text... </code> See wiki editing HELP for tables and other formatting tips and tricks.