Setting fall-back values for sensors

[Dennis_Zx7r]

Is there some way of setting the limits of the expected sensor values to trigger fall back, especially for the CLT?

Running current version of Ms2Extra. If I disconnect my (calibrated) CLT sensor to simulate a cable break, the MS calculates -18°C (0°F). This is potentially dangerous for the engine regarding cold advance of the ignition.
As I don't intend to ever have coolant temps that low (motorcycle), I would like to set my lower limit accordingly.

[benckj]

I wondered the same thing myself. OEM computers have a default value should the sensor either short or open circuit. Would certainly think the MS products would have same.

On a similar question, does the MS throw a code to tell you a sensor has failed? Not all of us run products which display real time sensor data like Shadow Dash.

jim

[grom_e30]

ms3 has a 'check engine light' function with limp mode strategy's

[Dennis_Zx7r]

There is a fall-back implemented I think, as the value is 82°C when no sensor is configured. But it doesn't work for me anymore after calibrating my sensor via the 3 point method. I assume the calculated resistance at that point is so high, that it's indistinguishable from a broken cable to the MS.

[DaveEFI]

Is there some way of setting the limits of the expected sensor values to trigger fall back, especially for the CLT?

Running current version of Ms2Extra. If I disconnect my (calibrated) CLT sensor to simulate a cable break, the MS calculates -18°C (0°F). This is potentially dangerous for the engine regarding cold advance of the ignition.
As I don't intend to ever have coolant temps that low (motorcycle), I would like to set my lower limit accordingly.

You could limit the effect in software settings? No fuelling etc correction outside your temperature range?

[jsmcortina]

Running current version of Ms2Extra. If I disconnect my (calibrated) CLT sensor to simulate a cable break, the MS calculates -18°C (0°F). This is potentially dangerous for the engine regarding cold advance of the ignition.

This doesn't sound normal? That out-of-range value is set when you calibrate the sensor through TunerStudio.

Technically, when you perform the 3-point sensor calibration, TunerStudio creates the lookup table that the firmware uses to convert voltage/ADC values into real-world temperatures. It then sends this lookup table to the firmware. When your sensor is unplugged, the ECU will see approx 5V on the input, this should land in a fallback part of the lookup table.

Did you calibrate the sensor through TunerStudio? What 3-point values?

James

[Dennis_Zx7r]

2°C, 5700 ohm
28°C, 1780 ohm
92°C, 225 ohm

BiasResistorValue 2490ohm

[grom_e30]

This doesn't sound normal? That out-of-range value is set when you calibrate the sensor through TunerStudio.

i have had my microsquirt powered up on the bench in the past without the mat and clt sensor connected and they both show -18

[Dennis_Zx7r]

I just measured the voltage on the IAT and CLT pins. Both 5v, as expected. IAT falls back to a reasonable value (21°C), CLT falls back to -18°C.

Have removed cold advance in the (not used) lower regions as suggested, so I guess that's a workaround.

The problem definately is the calibrated value! If i use 5429 (2°C) or above, fall back goes to -18°C. At 5428 and below, it falls back to 82°C!