modbus
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Thread: modbus

  1. #1
    Join Date
    Sep 2004
    Posts
    158
    the new Eng-Air cooling control c-trac 3 supports modbus and can be connected to a pda/notebook thru the serial port,for troubleshooting and configuring.my question is about modbus,i read that its used mostly in industrial controls,is this an open protocol and also why is it not used much in hvac control or is it?

  2. #2
    Join Date
    Sep 2005
    Location
    SF
    Posts
    14
    There are many systems that "talk" modbus. It is a basic open protocol that many gateways in HVAC controls industry can speak. What do you want to do with the units? Control? Scheduling? Monitor?

    Based on your answer you can select a system.

    Some options include fieldserver (interface only) or EnFlex (CONTROL, MONITORING AND SCHEDULING @Enflex.net) OR KMC or most large control system manufacturer.

    The interfaces to modbus vary from very simple to complex.

  3. #3
    Join Date
    Jul 2005
    Posts
    10
    I used modbus now one about 15 jobs. I use it to interface to VFD's mostly and a few ref. monitors. Most VFD manufactures use it as a protcal to interface. From my experience it is a slow way of communication but since VFD's put off lots of noise it seems to be less susceptible to noise. I know it does take some effort to get working, ussually i end up reading a 50 page manual on the vfd to reference all the registers.
    what software are you using on the laptop to talk to the device?

  4. #4
    Join Date
    Sep 2005
    Location
    SF
    Posts
    14
    I would not recommend using a laptop to make this system work. You will need a controller that talks both Modbus and whatever else you have to input and output to the rest of your system.
    If no other system you can find a small PLC that talks Modbus and allows for 4-20 mA or 0-5 inputs and outputs ( inc. digital).

    Does this make sense?

  5. #5
    Join Date
    Sep 2004
    Posts
    158
    thanks all-i havent got the software yet but it is available from Eng-Air.

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