solejnicz (asker) Dec 25, 2009:

I see there is too much uncertainty to close the question at the moment.

Yasutomo Kanazawa Dec 18, 2009:

Source text looks like a machine translation.

solejnicz (asker) Dec 18, 2009:

Yes, it has been poorly written, and I think it has been translated from Chinese. I have had this problem more often with the same client. I also think "30°" should in fact be "30%".

Tony M Dec 18, 2009:

Flawed EN This EN seems very poorly-written, almost nonsensical in places. It seems likely that it is either a poor translation from some other language, or has been written by a non-native EN speaker. Hence any interpretation is likely to be based on a degree of uncertainty and speculation.

In particular, it is not clear just what the relationship is between this air flow, the stepper motor, and the throttle setting. Also, I am wondering if that is indeed 30°, or should in fact be 30% — which could obviously make a big difference!

My understanding is that, in addition to whatever action the stepper motor has on the throttle setting, there is also some other control over airflow, which needs to be compensated for up to 30° (or %) of the throttle setting, above which threshold it has little effect and so compensation is not necessary. The precise details depend of course on the rest of your context.