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FanMagic8

FanMagic8® - is a hardware-firmware device that realizes a temperature-based switch mode automatic-fan-speed control with 2 independent channels and 2 fan speed vs temperature profiles which correspondent to the channels. The FanMagic8 is easy to use, require no special software overhead and is therefore the ideal choice for implementing thermal management in a variety of systems.

FanMagic8® realises remote monitoring and control through the following interfaces:

  • Serial, 3V logic level, it is base interface for all FanMagic8 family
  • Serial, -12V..+12V RS232, just for "R" option (FanMagic8-R)
  • USB, just for "U" option (FanMagic8-U)
  • Ethernet BASE-10T, just for "E" option (FanMagic8-E)

Both Channels A and B use Pulse Width Modulation Output Drive for Cost and Power Savings. Each Channel is able to drive up to 4A load and allows to connect up to 4 standard 12VDC brushless fans with 3-rd wire (tacho-generator) and provides regulation by Pulse Width Modulation (PWM) from 0% to 100%. 0% PWM in the profile allows to shut the fans off for the temperature or up to a certain temperature, and then turn them on starting at a certain speed, and then ramp fan speed in response to temperature, and change the slope of the ramp once the temperature passes another threshold according to the profile. The profile is a user defined graph of fan speed (0-100%) vs temperature.

The FanMagic8 measures the temperatures for both Channels A and B and control the speed of attached fans based on those temperatures. Temperature data are converted from remote thermal sensing elements - thermistors and translated into a fractional (step 5%) fan speed from 0% to 100% according to pre-charted profile.

The FanMagic8 provides a PWM output for regulating fan speed. This low-frequency signal (~4 Hz to 100 Hz) adjusts the fan rotations per minute by cycling the fan motor on and off via an adjustable duty cycle. Duty on to duty cycle is PWM value ~0% to 100%. Chopped by PWM the power is applied to the fan through the Channel Driver (A and B).

The principle of controller operation is frequent measuring (3 times per second) and analysing of airflow temperature and rotation speed of attached fans as well as generating of the voltage applied to the fan according to preliminary charted matrix. The temperature interval step is 2ºC. The PWM step is 5%. The value of PWM that is associated with temperature interval could be changed and regulation curve could be mould individually. PWM value determines fan power and finally the rotation speed (RPM).

Measured values of the RPM are compared with tabulated points (individually for each fan). Normally functioning fan should not have the rotation speeds lower than threshold matrix values. In presented example the measured value of temperature (32ºC) and PWM value 60% determine the threshold rotation values for 1st, 2nd, 3rd and 4th fan as 1400, 2200, 4000 and 4100 correspondingly. Even if one of fans has rotation speed lower than pre-charted threshold value, the FanMagic8 detects it as a fault, chimes, lights the LED (optional) and redefines PWM as 100%. Thus, early diagnostics of fan failure is assured at the time when rotation (and cooling) ability still is not lost but fault has been detected and signalized. If quantity of fans and air performance are redundant, the early diagnostics allows to increase reliability of cooling system essentially, while fan speed-down at low temperature increases fan life and decreases acoustic noise of the most unreliable and noisy element of modern electronics – cooling fan.

Both tables of matrixes for both Channels are placed in nonvolatile memory and there are some ways for their corrections if needed. The picture on the right shows the screenshot for FanMagic8-E and Channel A profile as a user defined graph of fan speed (0-100%) PWM vs temperature table. Just remember that there is no recommended PWM of 5% and 10% since many fans don’t like to be run with that little power. Also, doble check your fan is 12VDC with nominal rotation speed from 1500 to 8000 RPM. The FanMagic8 does not measure the fan RPM correct if this value is lower than 500 and higher than 8000.

The FanMagic8 (matrix) can be tuned up to determine individual handling characteristic both for PWM temperature characteristic and for attached fan behaviour in real use environment. Reducing of the fan speed as the temperature drops minimizes the system acoustic noise, prolongs fans service life period, diminishes power consumption. The FanMagic8 assures early diagnostics of fan failures and increases reliability of hardware functioning due to the overall monitoring of cooling system and signalling in case of failures. The use of the FanMagic8 combined with the system with redundant cooling facilities allows to design fault-tolerant system with long-life performance.

click to vew large picture

FanMagic8-E can be used as remote reboot solution for up to 6 controlled devices (servers) with just a few clicks. It means than FanMagic8-E does not require the physical presence of people to reboot a remote frozen computer. To do it the FanMagic8-E has to be equipped by logic level controlled switch which pushes the reset button by closing the contacts on your controlled device (Motherboard).

Here below is shown the OpticReset6 board which contains 6 infrared LEDs and could be used as option for the DC61 and DC62 cluster chassis.

The OpticReset6 board is connected to the FanMagic8-E by 10-wires ribbon cable. Hereby, we have 6 free space optic channels with narrow-beam infraread emitters. Just place 6 phototransistors opposit each of 6 LED and get your FanMagic8-E + OpticReset6 based remote reboot device ready! The phototransistor acts as controlled switch. Of course, you have to connect phototransistor to the motherboard as reset button keep correct polarity. Also, you can use your own switch to buid your remote reboot device. The simplest and cheapest is logic level MOSFET.

click to vew large picture
Temperature measurement
2 channels of temperature remote sensing (using remote thermistors cable, 440mm)
Signalling
Chime (buzzer)
LED, Optional
Connected Fans
- up to 8 pcs. of 12VDC fans with 3-pin connector (3-rd wire is frequence generator - tachometer. Nominal rotation speed of fans from 1500 to 8000 RPM. Max. load for the channel is 4A, but total load for the device should not exceed 6A.
Operating Environment
Operating Temperature Range: -20~+50ºC
Measuring Temperature Range: -10~+80ºC (2 sensors)
Power Supply
- 2-pin terminal block.
+12VDC 0~6A (fan's depended)
Dimensions:
Height: less than 25mm
Width: 33
Length: 100
Net weight: less than 0.1kg
Base interface
- serial, 3V logic level, 115200bit/s, 8 bit, no parity, 1 stop bit operation.
FanMagic8-R interface
- serial, -12V..+12V RS232 level, 115200bit/s, 8 bit, no parity, 1 stop bit operation.
FanMagic8-U interfaces
- Base serial and USB (min-USB BF connector).
FanMagic8-E interfaces
- Base serial and Ethernet 10BASE-T (RJ45 connector).
Controller FanMagic8-E in chassis DC61
click to vew large picture
... coming soon ...
Controller FanMagic8-E in chassis DC62
... coming soon ...

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