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Summary of change:
Make a '''test circuit''' (cheap 2 resistors used instead of the LSU4 sensor) for initial WBO2 pump_pw_zero and nernstdc_target (or even pump PID) calibration: Pump- (100Ohm) Nernst (100 Ohm) Pump+ * '''Rm'''=100 Ohm between nernst and pump- * '''Rp'''=100 Ohm between nernst and pump+ * measure the resulting voltage (with DVM, DC voltage mode), '''with the pump- signal as base. Connect the DVM black wire to pump-''' Typical voltages with wbo2 OFF (engine not running, trigger signal not played) * pump- : 0V (what we measure against) * GND : -4.1V (since we measure against pump- that is +4.1V above GND) * '''Adjust wbo2_pump_pw_zero until OK'''. Higher value results in higher voltage, typical calibrated value: 0x65+-03 (that is 101+-3). Restart before measurement, but after the changed wbo2_pump_pw_zero is saved ** nernst: +-2mV (/100 Ohm) ** pump+ : +-4mV (/200 Ohm) Typical voltages with wbo2 ON (engine running or trigger signal played or wbo2 forced on with mde02 command) * pump- : 0V (what we measure against) * wbo2_pump_pw_zero can be calibrated this way, usually 0x65+-03 (that is 101+-3). Restart before measurement, but after the changed wbo2_pump_pw_zero is saved ** nernst: +450mV +-30mV '''Adjust wbo2_nernstdc_target until OK'''. Higher value results in higher voltage. Typically 0x86 +-5 (that is 134+-5) ** pump+ : appr +900mV (is required here so the nernst voltage will be 450mV above pump- .... but the exact voltage here is not very interesting as nernst is used for feedback) ** '''note: 12V or higher supply voltage needed for this test'''. The pump will not maintain target nernst voltage with this test-setup if VBATT<12V ---- '''Misc notes''' * wbo2_pump_pid_kd=00 (I doubt that any other value makes sense) * wbo2_pump_pid_kp=20..40 ... too high value will result in significant oscillation. * Make sure the multiple of config values: '''wbo2_pump_pid_ki * wbo2_pump_pid_ilimit''' is high enough. If this is too low, pump+ will be limited: as a result, nernst_dc_target can not always be reached. ** I revised a theoretical reasonable maximum for the multiple : '''wbo2_pump_pid_ki * wbo2_pump_pid_ilimit''' (sg. like 0x80 * 0x0A) but in practice '''0x80 * 0x40''' was used to reach target. ** the PID integral term will rail faster for lower pump_pid_ilimit Don't connect real sensor until PID (and nernst_dc_target) is tuned with that so nernst is stable and fine (450mV above pump- ). [http://megasquirtavr.sourceforge.net/manual/Detailed.Sensor.Wide.html#Install [Detailed.Sensor.Wide.Install]] ---- '''See also:''' GenBoard/WideBandPumpPwZero GenBoard/Manual/WBSensor GenBoard/Manual
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