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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: This page is intended to document the actual method to WBo2 calibration for Vems 3.x process in one location in an easy to understand format for use with a windows box and MegaTune '''Instructions for calibrating WBO2''' These instructions are for bench calibrating your WBO2 There are two steps. *Calibrating the pump_zero *Free air calibration ---------------- '''Calibrating pump_zero''' ''This portion is a non-issue if you purchased a v3.3 and got an email with the pump_zero value in the email from the webshop. '' You will be changing this value [ Highlighted box in MegaTune ] Turn on VEMS unit. Leave trigger off ( no rotation of crank or no stimulation of box) Leave WBO2 off This is a fresh boot only power applied. hook up a Voltmeter between pins 5 & 6 [see photo] of the WBO2 connector [see photo] from the EC-18[photo] and measure the voltage. [Overall cartoon] This voltage is "as close to zero as possible" * you ask what does this mean. Well the variable Pump_pwm_zero has a digital output that has 256 values over 5 volts. So each point adjusts the voltage 19mV == 0.019 Volts. * Change in value direction. If you follow the picture above with the positive and negative leads for your VoltMeter. Changing the value Up one point will move the pump_pwm_zero up 19mV, otherwise it will drop 19mV. * '''IMPORTANT''' After you change the value in MegaTune for the pump_pwm_zero you have to "burn to eeprom" and reboot the VEMS box to make the changes take effect. You have to do this each time to see a change. * Tolerance Until told otherwise the tolerance is +/-20mV or +/-0.020V * '''All readings are taken in DC mode. ''' * Typical values are between 92 and 107 ---------------- Free Air Calibration Now that the pump_pwm_zero has been set you are ready to do the free air calibration. You will be changing this value [ Highlighted box in MegaTune ] * a change is this decimal value equates to a change of about 0.4% free Oxygen * Note: The bar across the bottom of the Megatune main page with green and red dots are for air fuel ratio NOT Free oxygen. * get up and running mde02 can also turn it on. Manmlp07 shows output changes for pump cal dont take effect until you reboot v3.x The current flows thru a 510 ohm resistor and a 10kohm resistor. measuring the voltage is a valid test. The question is what is the allowed tolerance. 5V / 256 = 0.019 V / bit +/-20mV is minimum 170 changed to 20.0 (3.824) 175 changed to 20.3 (3.843) 180 changed to 20.5 (3.863) 185 changed to 20.9 (3.882) 186 changed to 21.0 (3.882) 190 changed to 21.2 (3.902) minicom in r30 Manmlp07mllbyebye Man moves to comm mode mlp07 changes to WBO2 setting mll displays content byebye ends terminal mode and returns to megatune <code> 5V / 256 = 0.019 V / bit +/-20mV is minimum 170 changed to 20.0 (3.824) 175 changed to 20.3 (3.843) 180 changed to 20.5 (3.863) 190 changed to 21.2 (3.902) 185 changed to 20.9 (3.882) 186 changed to 21.0 (3.882) </code> I guess we should recommend a starting value (RCal=115 Ohm or so), and get the user read the O2% in free air. We make a table which the user can look up in 1 step => voila: WBO2 is calibrated. 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.