Ellison Computer Room Temperature Alarm Sensor

Winland Electronics Temp Alert TA-2HLD (TA)

This is a little tour of the Winland Electronics Temp Alert TA-2HLD (TA) unit that graces the North wall of the Ellison computer room. The Temp Alert is connected to our alarm system. If the Temp Alert determines the computer room temperature is outside preset limits it triggers the computer room alarm. The alarm company will then telephone people on their list of ICESS people so someone knows the situation requires attention.

There are three buttons on the TA, labeled: PROGRAM, DISPLAY LIMITS (up arrow), DISPLAY LIMITS (down arrow). The first thing to note about these buttons is that they are a little particular about how long they are pressed. If you punch them too quickly (like at the speed you would type) your keypress sometimes won't register. They seem to prefer a keypress that lasts for 1/4 to 1/2 of a second. Longer than that and you will activate a repeat function.

If a key hasn't been pressed for about a minute, the TA reverts to a steady-state display of the current ambient temperature, for example:

          f
       78  1

Press DISPLAY LIMITS (up arrow) and you get a display of the upper temperature limit, for example:

    hi    f
       85  1

Press DISPLAY LIMITS (down arrow) and you get a display of the lower temperature limit, for example:

          f
       32  1
    lo

Press PROGRAM and you get a display of the delay, in minutes, before the alarm is activated, for example:

       d15 1

The values displayed after hitting PROGRAM can be modified by hitting the DISPLAY LIMITS up arrow and down arrow buttons.

Press PROGRAM again and you get a display of the upper temperature limit, for example:

    hi    f
       85  1

Press PROGRAM again and you get a display of the lower temperature limit, for example:

          f
       32  1
    lo

Press PROGRAM again and you get a display of the ambient temperature bias used to calibrate the steady-state temperature display of the TA. This value can be positive, negative, or zero. It is added to the raw temperature value obtained from the TA's internal temperature sensor. The result (the sum of the bias and the raw temperature value) is what gets displayed during steady-state and is used as the final value for determining whether or not to trigger the alarm, as an example, the bias display might look like:

    hi    f
       -3  1
    lo
If the TA's internal temperature sensor says the current temperature is 81 and the bias value is -3, then 78 will be displayed and used as the value to determine whether or not to trigger the alarm.

Press PROGRAM again and the TA will, after a delay of a few seconds, return to the steady-state ambient temperature display, for example:

          f
       78  1

Here is our own copy (not a direct link), dated Fri Jul 13 2001, of the subset of the Winland Electronics web site that talks about the TA. A manual did not appear to be available on the web site at the time of this writing.

Last update: Fri Jul 13 17:44:40 PDT 2001, em@icess.ucsb.edu