I'm only giving it 4 stars because there are no instructions. Besides that it works great ( using it to control the fans for my rv fridge air circulation)

Wanted to use this to control the loud fans in my server, but it doesn't work at all.I cant get the tach signal or PWM control to work at all. That's this thing's whole purpose!My background is in electronics engineering and repair. I thought, with that knowledge, surely I would get this to work, but no. Not possible apparently.Using an oscilloscope, I was able to determine, that with no load, the PWM runs at 20Khz, as advertised.As soon as a fan is connected and system is under load, the frequency drops to 10Khz which is well below what the fans are rated for. As a result, the fans just run at full speed all the time regardless of what the controller is doing.There is no way to increase the frequency after this point.Don't buy this. It's just ewaste

I have 8 fans rated for 12V 3.3A each from some old 4U servers. I wanted a way to control their speed and this controller works wonderfully! I have the power split so the fans don't get their power from the controller. The controller is only used to show the RPM and control the fan speed via the PWM wire. These fans can slow down to about 20W for all 8 but they won't turn off which is probably a limitation of these fans and not the controller.

This was the perfect solution to add thermostatically controlled PWM fans to maintain constant temperature in my 3d printer enclosure.- Wide input voltage range means you won't need a buck board as long as your fan voltage and input voltage are the same.- Easy to program- another reviewer posted easy-to-follow instructions.- PWM frequency selectable 20khz or 2.5khz so make sure your fan PWM frequency is close to either of these or PWM won't work properly.- 4 stars instead of 5 because the fan connector is basically impossible to find. I soldered a JST sm 4 pin connector instead.

This product does not come with instructions. That being said i used someone else review and his instructions were great. had it running how i wanted in less then 15min.

Device works as described except the 4-pin white connector is larger than a standard computer (PC) 4-pin fan connector. I had to make my own dongle to adapt.

According to the image, and like, standards, pin 1 and 2 on a wire fan are - and + respectively. I lost an hour of life because I didn't notice the little "-" on my multimeter when I was troubleshooting this. Other than that, it does that it says on the tin.

There were no instructions at all. Could not find anything online either. Figured out the button sequence to set temp and RPM rate (I think).Connected to a brand new Noctua NF-P12 Redux PWM 120mm fan.The LED display alternates between current temp and fan RPM but is not displaying fan speed. Temp is displayed accurately.The controller also appears to shut the fan down at >40 C. Not what I expected.

The controller I use on a Home Mod case. I had to go to Digikey to get the proper connector. TE Connectivity AMP Connectors (3-643818-4) DK PN A31365-ND the connector I use and it's for 20 Guage wire. While I had to mod this connector the Specs are correct. Fits tight no issues.BTW this controller is Awesome. Can fully control a 4Wire fan (off, on, with ramping fam speeds), & also can control a relay to power up another fan if needed, via that relay.iQuack

The jury is still out on whether I can control a couple of EBM fans I have tried with this PCB. The instructions are not complete from this Amazon Item Description section. I did find the full instructions from another location, were not intuitive or understandable, but I was able to clean them up once I figured out how this board works.I am able to power the PCB on, and adjust all the parameters, I can trigger the 'RUN' light on or off by manipulating temperature to the probe (or set C__ to C0 to disable cutoff forcing fan to RUN mode constantly). I am not yet able to get it to control the EBM fan though. If I disconnect the PWM wire from the PCB to the EBM fan, it turns on to full speed (PCB display shows the RPM signal working as well), but when I plug the PWM wire back into the fan, the fan stops. I'm not sure what kind of PWM signal this EBM fan I have requires. I have tried setting the PWM frequency parameter on the PCB from default 20kHz to 2.5kHz, and tried the 'reverse' PWM parameter, and it makes no difference.I will continue to play with this, I have a simple 2-channel oscilloscope I will hook up and try to see what the PWM signal looks like coming out of the PCB, and also see if I can determine what kind of PWM signal the EBM fan is expecting to see for its range of speed control.I am hoping to get this going as I had high hopes, because the item description indicated that this PCB 'supports EBM four-wire fan'...I will come back and update my review later if I can make any progress on this. I have also reached out to the seller to see if they can provide any further support or advice on this unit. The rest of the PCB seems to function as it should, relay circuit on/off, alarm output, temperature probe can trigger on/off RUN mode indication, I am only not able to get the PWM signal they provide to interact with my EBM PWM fan.Pasting my own cleaned up instructions below -NOTE: These instructions are not official from manufacturer, these are my own interpretations of the PCB function, adapted for my own understanding, perhaps it can help others.----------------------------------INSTRUCTIONS:----------------------------------1. Description:This is a PWM 4-Wire Fan temperature controller. It can be used for industrial fans.2. Features:1. Digital LED display2. Supports EC four-wire fan control3. Supports low-temperature fan shutdown4. Wide voltage operation5. Supports anti-sequence fan6. Supports EBM four-wire fan3. Parameters:1. Product Name: PWM 4-Wire Fan Temperature Controller2. Working Voltage: DC 11V ~ 55V3. Working Current: 0.1A (MAX)4. Fan Current: 5A (MAX)5. PWM Range: 5% ~ 100% or 0%6. PWM Frequency: 20KHz / 2.5KHz7. PWM Signal Amplitude: 10.5V (no load)8. Temperature Measurement Range: -9.9℃ ~ 99.9℃9. Working Temperature: -25℃ ~ 85℃10. Working Humidity: 5% ~ 95% RH11. Sensor Wire Length: 1 meter12. Size: 70.5 x 40.5 x 13.5mm4. Notes:1. This product is mainly designed for industrial fans.2. The user interface is different from conventional PWM fan controllers. The direct shutdown feature only supports PWM fans with a signal shutdown function (fan stops after the PWM speed control line is grounded).3. If additional fans need to be shut down at same time as the primary PWM fan, they can be controlled to cut off power through the external relay trigger circuit, supplied by the 'relay' header on the PWM controller's PCB.5. Interface Introduction:1. Power interface: The main power input interface (11v ~ 55v): + | - | Supplies the main power to the control board PCB, also providing the power to pass through to the fan output interface.2. Fan interface: Fan output interface (4-pin): Fan + | Fan - | Temp Sense | PWM output3. Temperature probe interface (2-pin): Connect NTC probe parameter 10K B=3950.4. Alarm signal port (2-pin): High-level output during normal operation, low-level output when the fan is abnormal.5. Relay interface (2-pin): Expansion interface. Drives a 9V or 12V relay, which can be used to control an addtional fans power circuit, when the fan control stops (the 'RUN' LED indicator turns off), the relay opens.6. Button Description:1. + and - Buttons: Short-press buttons to switch the display mode, + or - is also used to increase or decrease a value during parameter setting (long-press to increase or decrease a parameter quickly).2. OK Button:2.1 With the PCB powered ON, short-press the OK button to enter the inherent PWM output setting, the range is 5% ~ 100%, short-press again to save and exit.2.2 With the PCB powered ON, long-press 'OK' button to enter the temperature parameter setting. After entering, modify the first parameter (L__) by pressing the + Button and - Button. When the 'L' setting is as desired (e.g. L35), short-press the 'OK' Button to save and move to the next parameter adjustment (H__), modify by pressing the + Button and - Button. When the 'H' setting is as desired (e.g. H45), short-press the OK Button to save and move to the next parameter adjustment (C__), modify by pressing the + Button and - Button. When the 'C' setting is as desired (e.g. C25), short-press the OK Button to exit the temperature parameter adjustment mode.L = Acceleration Temperature | H = Full Speed Temperature | C = Turn-off Temperature2.3 With the PCB powered OFF, hold down the 'OK' Button, turn ON power (while holding down 'OK' button) until it enters the function setting (F__), modify parameters with the + and - Buttons, short-press the 'OK' button to move to the next parameter, you can set the PWM output frequency 20KHz / 2.5KH (the display will show "F20 / F2.5") in turn. PWM output direction forward/reverse (the display show "P1 / P-1", short-press the 'OK' Button again to save and exit.7. Explanation of Temperature Parameters:1. Acceleration Temperature (the display showing "L**", "*" stands for the number): The range is 5℃ ~ 94℃. When the temperature rises and exceeds this temperature, the PWM output starts to increase as the temperature rises.2. Full Speed Temperature (the display showing "H**"): The range is 10℃ ~ 99℃ . When the temperature rises or exceeds this temperature, the PWM always outputs 100% and the fan runs at full speed.3. Shut-down temperature (the display showing "C**"): Low-temperature shutdown temperature. The range is 0℃ ~ 92℃. When this value is set to > 0, the low-temperature shutdown function is enabled. When the temperature is lower than this temperature, the output is turned off (PWM signal and extended relay output are turned off at the same time). When the temperature rises above the acceleration temperature in the off state, the fan restarts and changes speed with the temperature, if the shutdown temperature is set to 0, the low temperature shutdown function is disabled, and the PWM and extended relay output interfaces will always output.4. The difference between the acceleration temperature and the full speed temperature must not be lower than 5℃, and the difference between the closing temperature and the acceleration temperature must not be lower than 2℃. If the value will break the above temperature difference when modifying the parameters, the program will automatically adjust the other two parameters.8. Show Description:1. "X10 RPM": Speed unit displaying. When this light is on, the display is currently indicating the fan speed, which is the value after the speed divided by 10. For example, if the display indicating is 256, the actual fan speed is 2560 RPM (revolutions per minute).2. "℃": Temperature unit displaying. When this light is on, the display is currently indicating the temperature measured by the current probe.3. "RUN": Fan running indicator. This light illuminates when the fan is running, and goes out when the fan is off. Note that this is the control status, not the actual fan condition. If the fan fails, the alarm signal port outputs a low level during operation (when the RUN light is on).9.Package:1. 1pcs PWM 4-Wire Fan Temperature Controller2. 1pcs NTC Temperature Sensor.