Hi Jean, > -----Ursprüngliche Nachricht----- > Von: Jean Delvare [mailto:khali@xxxxxxxxxxxx] > Gesendet: Montag, 30. August 2010 10:24 > An: Leo Krüger > Cc: lm-sensors@xxxxxxxxxxxxxx; Thomas Ettwein > Betreff: Re: small changes in configuration file for MSI > IM-945GSE-A > > Hi Leo, > > On Sun, 29 Aug 2010 01:16:17 +0200, Leo Krüger wrote: > > I own a MSI IM-945GSE-A motherboard and used the sample configuration > file > > from http://lm-sensors.org/wiki/Configurations/MSI/IM-945GSE-A, > > which showed me around 14V for the 12V output. > > I'm adding the original author of the configuration file to Cc. > > > Since this would be far above specification limits, I measured the > actual > > values at the ATX power connector. In addition to the 12V output, the > 5V > > and the 5Vsb line differed a little. > > I am a little curious about your experimental setup. How do you get > access to the ATX power connector while the system is running? For my atx power connector it was possible to get to conducting parts with a small test prod. > > I usually measure +5V and +12V from molex connectors, it's easy. But > 5VSB, I wouldn't know how to measure it. > http://en.wikipedia.org/wiki/ATX#Power_supply the purple wire is 5vsb > > Below is my updated configuration file. Note that I just changed 3 > lines, > > the compute lines for in4, in5 and in6. > > It would be nice if you could update the sample file in your wiki. > > Let me know if any additional steps are necessary. > > It is expected that measuring the values with a multimeter will lead to > slightly different results for voltages which need scaling. Scaling is > achieved using two resistors, the value of which is typically > guaranteed to 1%. Therefore, there can be up to 2% of error introduced > by the resistors themselves. By calibrating your configuration file > based on actual measurement, you correct this error for your specific > motherboard, but the same correction doesn't apply to other instances > of this motherboard model. > > So your proposed changes may be perfect for your board, but aren't > suitable for the default configuration file for this board. > > A better way to figure out which scaling factors are intended by the > board manufacturer, is to compare with what the BIOS is printing. First > write down all values reported by the BIOS, and also note your > voltmeter measurement. Then do the same again with lm-sensors's > unscaled voltage values. If the voltmeter values didn't change, then > lm-sensors should report the same as the BIOS after scaling. If the > voltmeter values changed (which can happen as the system load is > slightly different) then you have to take it into account in your > computations. I've to admit that this sounds much more reliable than my simple measurements. To check your proposed factors I'm going to do it the way you suggested. Afterwards I will give you an acknowledgement. I've access to two of these motherboards, so I will check if the results differ. > > The 5.25 scaling factor comes straight from the datasheet (suggested > resistors of 200k and 47k), and your own measurement for +5V leads to > almost exactly this, so I wouldn't change it. It is also quite unlikely > that the vendor would use different resistor values for +5V and 5VSB, > which makes me reluctant to change 5VSB either, although your proposal > is quite different there. Ok. I think you're right. The difference is quite marginal. > > For +12V, the 12.83 scaling factor was apparently copied from our old > default configuration file, which for this chip was written for an > Epox board. The datasheet instead suggests to use resistors of 200k and > 20k, leading to a scaling factor of 11. Note that the difference > between this 11 and your 10.86 is less than 2%, so it is likely that > MSI followed to the datasheet. So I would go with 11. > I just found the datasheet http://www.fintek.com.tw/files/productfiles/F71882_ab.pdf To which one do you refer? Please let me know if I can do anything else. Especially if there is anything I can do to provide you with hardware specific data to support development of lm-sensors (I actually don't know if there is support missing for any of the hardware parts) Regards, Leo > -- > Jean Delvare > http://khali.linux-fr.org/wishlist.html _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
