Installation/Testing

Before Installing the Fan Master in my computer, I performed a thorough testing of the unit on the bench. I have a bench power supply that I use for testing my custom projects, and this proved to be the most convenient way to test the outputs of the fan channels and the temperature probes. When I first powered up the Fan Master, I was pleased by the layout of the LCD Screen.

The Fan Speed readout is on the right, and the temperature readout is on the left. On the lower right it shows the current fan channel displayed.  Although it's hard to see in the picture, the temperature probes are listed as "CPU", "Case", "HDD", and "Power Supply" on the upper row of the display.  You could always put the temp probes wherever you want to, but the labels for each are listed as such. The first test I put the device through was to test the voltage output of each channel.

I used my trusty multi-meter to test the outputs of each channel.  Each channel posted an output of approximately 6.5 Volts at minimum turn (suitable for most fans, but possibly below the stall speed of some larger fans).  The maximum of each channel was right at the input voltage.  My test power supply (scavenged from an older machine) runs about 11.78 Volts on the 12 volt line, and each channel achieved this at maximum turn. I decided to test the linearity of each dial to see what range and sensitivity the dials provide. I tested each channel at five positions: Minimum turn, 9 O'clock, 12 O'clock, 3 O'clock, and maximum turn.  Here's what I found.

First, my fingers are not precision instruments, so the relative dial positions are not exact (although they are pretty close).  Even so, I noticed a few things.  Each channel was pretty close to the others with the exception of channel three, which was consistently a little higher for a given position, by around a half-Volt. The voltage of every channel tended to ramp rather quickly, achieving the maximum output voltage well before the maximum turn.  This has the effect of making the last quarter-turn of each dial essentially useless.  This is probably a function of the voltage regulators used, but its effect on fan RPM should not matter.  My main concern was to find out if the dials reflected a useful voltage range, and based upon my experience, I do find this to be the case.  Most fans stall around 6-7 volts, so this is probably a safe speed for the majority of fans.  The dials operated smoothly, and felt sturdy.  Note that there is no provision to lock a channel into "always on high", so I wouldn't recommend using a channel for other 12 volt devices like cold cathode lights.  This is because most CC lights require a full 12 volts for the inverter to work properly, and if you turned down the channel by accident, it could cause the light not to function properly.  Super Flower doesn't remark on the use of the Fan Master for anything other than fans, so it's hard to fault them for this.

The next item on the list for testing was the temperature probes.  Each temperature probe comes with a factory preset for an alarm for each channel, which is displayed below the temperature readout.  If the probe is not connected, it does not send out the alarm.  However, if a temperature probe channel is receiving a valid signal, and then that signal is lost, the alarm is triggered. When I first attached a probe to the back of the device, it immediately began displaying the temperature.  The room temperature was about  20 degrees C.  I noticed that the sampling rate was pretty high; in other words, the temp readout changed rapidly with variations in temperature, which would be helpful in the instance of a CPU fan failure.  The temp readout goes down to tenths of a degree C, and I was able to make the temperature vary simply by blowing on the temp probe.  Pretty sensitive!  How accurate are the probes?  Well, I devised a way to test this based upon the Celsius scale.  0 degrees C is defined as the freezing temp of water, and 100 degrees C is defined as the temperature when water boils. No place in the documentation does it mention the temperature limits of the probes, so I figured the next series of tests would be broad enough for both extremes (possible exception is below ambient super cooling such as Peltier cooling, vapor-cycle or other cryogenic cooling setups). The freezing test was easy: Submerge a probe in water, set it in the freezer and wait. When I retrieved the probe, I was surprised to find that the unit would not detect it at all. No alarm, no readout (not simply a zero readout, but the "no signal" readout of a dashed line). I figured maybe I messed up the probe, but when I hooked up a second probe and touched it to the side of the container of ice, I watched the temperature decline rapidly towards zero and then the alarm went off.  Apparently, when the probe registers zero, it sends the logic program to infinity or something, and the unit registers it as a "dropped signal". Good to know if you plan on using the probes to monitor the temperature of sub-zero devices.  In all fairness, most off-the-shelf cryogenic coolers come with their own monitoring systems.

Next up was the opposite end of the spectrum. This test proved to be a little more difficult.  I planned to boil some water on the stove, pour it in a mug and then take it to the lab to test the probe. Well, as many of you science buffs know,  a hot liquid cools at a rate proportional to the difference in its temperature and that of ambient.  In other words, boiling water doesn't stay boiling long once it is removed from heat.  Even so, I was able to register temperatures of around 80-85 degrees C.  You should have seen me rushing with a boiling cup of water from my kitchen to the Lab. I figured hooking up the Fan Master anywhere near the stove would just be asking for trouble. So this test was inconclusive, but I figure that these probes will span the typical range of most enthusiasts' setups without problems.  If you get a component up to 80 degree C, it will probably fail anyway.

 

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