Xenta 121 temperature calibration precision problem


Xenta 121 temperature calibration precision problem

Product Line

TAC Vista


  • Xenta 121
  • ZBuilder


Calibration of a temperature input on a Xenta 121 controller is limited to whole increments in degrees Celsius.


To allow greater precision in calibrating thermistor inputs on the 121 in either Fahrenheit or Celsius do the following.

Note: Any LonMaker drawings or LNS databases that are open ought to be closed (and backed up) before doing this.

  1. In the file C:\LonWorks\types\User\TAC\Xenta100.fmt, find the following three consecutive lines:
    UCPTIOOffsetB1: text("%d");
    UCPTIOOffsetB2: text("%d");
    UCPTIOOffsetU1: text("%d");
  2. Replace with the following six lines:
    UCPTIOOffsetB1#SI: text("%f");
    UCPTIOOffsetB1#US: text("%f", *1.8+0(0:855));
    UCPTIOOffsetB2#SI: text("%f");
    UCPTIOOffsetB2#US: text("%f", *1.8+0(0:855));
    UCPTIOOffsetU1#SI: text("%f");
    UCPTIOOffsetU1#US: text("%f", *1.8+0(0:855));

This will allow precise calibration in the user's default temperature format.