Some minor set up issues...
Temperature Calibration
Temperature calibration seems to be reading low. The air sensor is [MSD 2320] with exposed thermistor (100k-50 Ohms), the coolant sensor is a [Land Rover] part. The following points were measured, using a DVM with K-thermocouple:
Coolant | Air | ||
Temp | Resistance | Temp | Resistance |
-16 | 6650 | ||
1 | 5420 | ||
3 | 5430 | ||
7 | 5370 | ||
20 | 2318 | 20 | 3190 |
21 | 2023 | ||
71 | 480 | ||
86 | 242 | ||
88 | 297 | ||
96 | 203 |
The air sensor sounds like a common NTC part? So are there scaling issues here?
WBO2 Voltages
Got the hardware completed. The issues seem to be getting it set up as described [here].
I took base settings from the above page, and found that 0x63 was closest to 0V for my board (-0.109V). Then inserted 100 Ohm resistors into the socket and took readings (nerst_dc_voltage=8D):
Circuit | Target | Voltage |
GND -> Pin 5 (pump) | 3.96 | 4.28 |
GND -> Pin 1 (nernst) | 4.41 | 4.39 |
Pin 1 -> Pin 5 | 0.45 | 0.11 |
Adjusting nernst_dc_target can change nernst value, but pump is still too high, and difference too small. The linked page states "The product of wbo2_pump_pid_ki and wbo2_pump_pid_ilimit should be around 0x4000" but linked values of 0x20 and 0xFF give 0x1FE0 already? Which is more correct, and how can I use this to increase the pump voltage (assuming nernst_dc_target can reduce nerst voltage independently). I think increasing wbo2_pump_pid_ilimit should work to raise the pump voltage? Or should I increase wbo2_pump_pid_kp instead? (after reading PID links)