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  1. #1
    Join Date
    Aug 2005
    Posts
    831

    Question floating point controller

    My boss wants to control 3 sets of dampers to control room temp with floating point actuators. Is there a off the shelf control to do this with or must I use some type of programmable control?
    eventu rerum stolidi didicere magistro

  2. #2
    Join Date
    Jan 2003
    Location
    USA
    Posts
    1,682
    There are a couple of off the self stats that can do this.

    Kele makes a few -

    http://www.kele.com/olcat/tc11/10306.html
    http://www.kele.com/olcat/tc11/11246.html

    Siemens also has some.

    Sorry don't have their product catalog in front of me at the moment. You could also likely get away with a staging stat and bang each damper open of a stage. ie three damper, three stage cooling stat.

  3. #3
    Join Date
    Jul 2007
    Location
    Sacramento, CA
    Posts
    250
    You might want to consider setting up a PID lop in logic to control the dampers and use temperature control to detemind position of the dampers. One signal can control multiply dmaper and set them in sync. So you can have the outside and exhaust work together and the return damper to be opposite of them. When the OSA and ECH open the RET closes at the same precentage.
    Hope to give you another idea for this, so not have to find specific controllers, but just off the shelf type that work on a 0 to 10 volt signal or ?

  4. #4
    Join Date
    Aug 2005
    Posts
    831
    Thanks, looks like the Kele T158 or TB6980 will work. A little more info: There is no BAS to tie into, so any programmable control would be the only one on site. The dampers are recirculating or exhausting process cooling air based on room temp. So they can work in parallel. Could I use the output from the T158 to power a relay to send the same signal to all 3 at once. Im assuming that the output from the control would not be sufficient to work all 3 at once. Using Belimo LMB24-3 actuators.
    eventu rerum stolidi didicere magistro

  5. #5
    Join Date
    Jan 2003
    Location
    USA
    Posts
    1,682
    T158 can handle 10VA on the output. LMB24-3 is 3VA. So that's three actuators to the stat. I didn't look at the other stat, it could be more...

    Putting a relay on a floating point output is a death sentence. They may last a million cycles, but you could be using a 100-1000 cycles each day.

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