Alerton TX-VAV controller
I recently replaced a TX-VAV controller because the Microset was not responsive. After matching all the dip switches and installing the new control the Microset is now responsive and I programmed the hi and lo cfm rates but the controller will not stop sending a close signal to the damper.
If I manually open the damper using the clutch on the actuator the CFM reads accurately on the Microset and goes to 0 as it drives closed.
Could a duplicate address on another TUX cause the vav controller to issue a close signal?
I would start by checking the actual airflow ( AF on the Microset ) . If this is reading low, then the actuator is going to drive 100% open. You could also check the Calibration Factor ( CF on the Microset ) on this controller. They come from the factory set at 104. If this was inadvertantly set to 0, this would cause the damper to drive wide open also.
Originally Posted by dc48
If your VAV controller is connected to an Ibex system, someone could have overridden DO-7 to the VAV which will force the box closed via software.
Thanks for the response.
Originally Posted by noskilltech
Can that be changed using the Microview?
I believe if they put it on the display you can, if not, you'll need an AC-2650 cable, one of their super duper proprietary software keys and the software to get in and change it. You might not need the cable if you have the database and the microview has a modem, then you could just dial in.
Originally Posted by dc48
If the point is not on the microview and they don't normally connect to the system with software I would highly doubt that the DO is turned on. I've seen weird glitches on ibex over the years, but it's usually the degree units switching to C° from F°, not damper close.
For those looking to build their own interface cable to some of these older HVAC devices, a cable similar to the function of an AC-2650, here is a project that I recently put together for less than a few dollars. These little Max232 boards with the DB9 connector can be purchased on Ebay for a couple of dollars and that will include shipping. I bought a couple of them for $1.50 each. Stay away from the boards that have the Max3232 chip. It's a 3volt version of the Max232, and although they say the chip is good up to 5.5volts, they run very hot at 5volts and I've had one burn up. If you do get a Max3232, I would suggest adding a resistor in line with Vcc. These handy little com boards usually come with the cable you will need. I added a 2.54mm 6P Pitch Dupont Jumper Wire Cable Housing. Using a pin or exacto knife the single housings can be removed and replaced with the 6 pin housing. I also added a dummy clip in position 6 for extra support and glued a square toothpick into pin 5. This makes it more convenient for attachment and prevents putting the connector onto the pins backwards. The board is configured as DCE so you'll use a straight through 9 pin cable, not NULL modem. It will be female on one end, male on the other. DTE to DCE.
Max232 board----6pin Dupont housing
-----------------Pin 5 - Block hole with toothpick (optional)
-----------------Pin 6 - Dummy connector (optional)
I've included pics of devices this cable will work on.
I've also included a communication test using HyperTerminal to connect for Configuring this Manufacturers Global controller.