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AMC6821PDK Auto Temperature Fan Control

Chris Casey
Prodigy 20 points
Other Parts Discussed in Thread: AMC6821

Hi,

I am having issues using the AMC6821PDK to auto temp fan control a 3-wire DC fan.  I need the fan to keep an object running at a specific temperature.  I have tried several different options in the software GUI and different jumper options for pin configurations and cannot get the hardware and software to respond how I would like or to respond at all.  If someone familiar with the product or even just familiar with auto fan temperature controlling units could contact me and assist me with the configuration of software used on this product it would be immensely appreciated.

e-mail: ccasey@mc.com

Thanks in advance,

Chris Casey

  • 0
    TI__Expert 6925 points

    Hello Chris,

    Welcome to the forum!

    Sorry it took us a while to reply your post. We usually expect AMC6821 related questions in the precision data converters forum. From now on, we will try to help you as much as possible.

    To begin troubleshooting this issue:

    First, could you verify the following jumper settings?

    1) AMC6821 EVM Board jumper settings for 3-wire fans:
    -  J5 should only have one jumper connecting pins 11 and 12. Remove any other jumpers in J5.
    -  W5 should have its jumper in the 2-3 position (to the right)
    -  W9 and W10 should be open since it seems the board is connected to an external sensing transistor
    -  All other jumpers must be in their default values as in Table 2 page 12 of the User’s Guide
     
    2) USB-MODEVM INTERFACE Motherboard SW2 settings:

    Second, could you share with us the part number of the external transistor used to sense the temperature of the object mentioned in your post?

    Third, could you tell us how this the external sensing transistor is connected to pins 13 and 15 of J4?

    Finally, could you send us the datasheet of your fan?

    Thank you,

  • 0 in reply to Rafael Ordonez
    Prodigy 20 points

    Rafael,

    I have verified all of the jumper and switch settings you mentioned.

    Second, could you share with us the part number of the external transistor used to sense the temperature of the object mentioned in your post?  The remote transistor I am using to sense the temperature of the object is 2N3904BU from Fairchild.  It is described as a Bipolar Small Signal NPN Transistor.

    Third, could you tell us how this the external sensing transistor is connected to pins 13 and 15 of J4?  The transistor is not connected to pins 13 and 15 of J4.  I have shorted the base and collector pins of the transistor together and have that inserted to the IN+ terminal of J3.  Then the emitter pin is inserted into the IN- of J3.  Of course, there are wires soldered to these pins to allow mobility of the transistor.

    Finally, could you send us the datasheet of your fan?  The fan is actually on a fansink purchased from CXAlpha.  What they have for technical information for the fan can be found in the following link.  http://www.micforg.co.jp/en/c_fhce.html

    Now,  I in the current configuration, I feel that the auto fan temperature control works as it should.  I have conducted some simple tests with the remote transistor sensing the temperature along with some thermocouples for verification and heating the object with a heat gun.  The fan seemed to respond appropriately with more or less heat base on the transistor reading.  My real issue now is that we will need to control 2 fans independently based on their own transistor readings.  I am not sure how simple or difficult this could be.  Is it easiest to use a duplicate of the setup and plug in another USB to the computer or can you monitor and control both independently with one set of boards?  Is it as simple as an address change or a switch on either board?

    Thank you for your help.  It is greatly appreciated.

    Chris

  • 0 in reply to Chris Casey
    TI__Expert 6925 points

    Hi Chris,

    Sorry for the delay.

    Thank you for the feedback and I’m glad you got the fan to react to temperature changes.

    The EVM software and USB interface hardware don’t support multiple programming of EVM boards.

    However, a USB to I2C tool like the Aardvark I2C is capable of programming more than one EVM board as long as each board has different addresses.
    This I2C tool can be purchased at:
    http://www.totalphase.com/products/aardvark_i2cspi/

    This tool can use a script to program multiple AMC6821EVMs. I have worked with this tool and the AMC6821 many times and I can easily make a script for you that will setup the auto temperature control of the fan for every EVM you want to use in the I2C bus.

    I will only need as much information about the way the fans should react to temperature changes.

    Besides, the script can be used as a reference to program the microcontroller intended to program the AMC6821s later on.

    Regards,