Hi David, I did some more research on the 4 pin fan. > > Fan2 seems to be connected to "CPU-FAN", the 4-pin connector. Here I am > > still experimenting. The main problem is that the CPU cooler I do use now > > has only 3 pins. If I connect any 3 pin fan to these 4 pins, the fan just > > turns at high speed - no control. Is there any adapter for such purposes? > > The pins on a 3-pin fan are (not in order): ground, PWM signal > (typically +12V, but the signal switches on and off rapidly) and RPM > sensor. The problem is that the RPM sensor is powered by the PWM > signal, resulting in an inaccurate RPM reading. The pins on a 4-pin > fan are (not in order): ground, PWM signal drives the fan, power for > the RPM sensor (I think it's +12V, or it might be +5V) and the RPM > reading. This gives a more accurate reading. If you found the ground, > PWM, and RPM pins, you could connect a 3-pin fan. You should use a > voltmeter, and you might still damage your board. (If, for instance, > the RPM sensor on the 3-pin fan outputs a +12V sense signal and the > motherboard is designed for a +5V sense signal, you could damage it.) > That's all I know on the subject, but you could google for a while and > look for more information. - pwm2 seems to work only in pwm mode. - pin 1= GND, Pin2 = +12v, pin3 = sensor, pin4 = speed control (as you indicated) When measuring pin4, it turns out that this delivers zero to almost 5 volts. This means that I cannot drive a fan directly but will need a transistor or so to translate to 0..12 V. > > No, the driver can only report readings from the chip. If the _div is > 128, the readings are as low as they can get. Erroneous readings are > typical at low speeds. One way to get a more accurate reading would be > to average multiple values (two options: a moving window average, or > an alpha filter) -- this is not something that a kernel driver should > do, in keeping with the lm-sensors design philosophy. The sensors > package might be the right place to add this feature, but I am not > certain. > can one extend the mesuremnt period in the driver? Best regards Chris ___________________________________________________________ Der fr?he Vogel f?ngt den Wurm. Hier gelangen Sie zum neuen Yahoo! Mail: http://mail.yahoo.de
