Zeroing the Leaf Temperature Thermocouple

The only calibration required for the leaf temperature thermocouple is its zero adjustment. It’s a good idea to check this at the start of each day; not because it drifts that much, but because it’s easy to do, and is part of good pre-operation practice. After all, if you have a broken thermocouple it’s better to find out before you make your measurements than after.

  1. Unplug the thermocouple connector
  2. Remove the male thermocouple connector by pulling straight out.
  3. Monitor TBlock and Tleaf
  4. Configure the New Measurements screen so that you can view both the leaf temperature and block temperature variables (Tleaf °C and Tblock °C, respectively). In the default display configuration you can view these variables by pressing H.
  5. Make them read the same
  6. There is a small adjustment screw located on the underside of the sensor head, near the rear of the analyzer housing (Figure 18‑15). Once the instrument has been on for about 30 minutes to warm up, use the small flat head screwdriver in the spares kit to turn the adjustment screw until the displayed leaf temperature and block temperature match.
  7. Figure 18‑15. Location of the leaf temperature zero adjustment screw.
  8. Reconnect the thermocouple connector.