Thermocouple Offset Setting and Cone Offset Setting

What they are, how to find them, and when to use which setting.

  1. Thermocouple Offset and Cone Offset are two different settings that allow you to control how much heat-work develops in the kiln by the end of the program. Basically they accomplish this by allowing you to raise or lower the final temperature that the DynaTrol calculates to shut itself off.
  2. The Thermocouple Offset setting allows you to add or subtract degrees from the kiln’s final temperature.
  3. The Cone Offset setting allows you to add or subtract degrees from what the DynaTrol determines the individual cone’s final temperatures to be.
  4. They are both located under the OTHER key. When the display reads IDLE, press OTHER again and again.

Cone Offset:

First up is Cone Offset which looks like CNOS. Press ENTER here to first set which cone you want to offset, then set how much of an offset you want to have. Very early versions of the DynaTrol only came with +/-50 degrees, while later ones come with +/-100 degrees. If the setting is already set to 0 and you want the kiln to fire cooler you must use a “9” in front of the setting; 9020 would 20 degrees cooler that the 0000 setting.

Thermocouple Offset:

A few OTHER presses past CNOS you will find TCOS or Thermocouple Offset. When TCOS comes up press ENTER and first you will see which TC you are about to offset. Press ENTER again and you will see how many degrees are currently offset for that thermocouple. This number is what you will be changing to make this zone of the kiln fire hotter or cooler. RAISE the setting to fire cooler, LOWER the setting to fire hotter. Use the “9” again as a prefix for a setting that is set below 0. While you can set each zone differently it is best to keep the settings within 10 degrees of each other to minimize the chances of producing an error code from the difference between an artificially higher/ lower temperature and the real set point.

Thermocouple Offset and Cone Offset can both be used to calibrate the kiln to a self-standing pyrometric cone. All this means is that when you program the kiln to go to say cone 6, it will do that and bend the cone over perfectly- not too hot or cool. If the cone comes out looking too melted or not melted enough Thermocouple Offset and/or Cone Offset can be used to adjust it hotter or cooler.

Lots of people call up and say the kiln fires too hot or too cool. It seems best to first calibrate the kiln to their glaze cone using Thermocouple Offset only. This usually only takes one firing but sometimes 2 or 3 firings is necessary.

If they say it fired more than a whole cone over where it should have, add 25-35 to the existing Thermocouple Offsets. If they say about a whole cone over add 20-25. If they say the cone was flat but still had the hump in the back add 15-20. 10 seems to be the minimum setting change in order to see a significant change in the cones.

Cone Offset is only seldom used; like for example if the customer complains that although the glaze firing is fine, the bisque firing is too hot or too cool.

Using Cone Offset on the bisque firing adjusts just a single cone number and does nothing to change the glaze firing. It is pretty rare to have to use both though. Usually they just care about the glaze firing.

Another time to use Cone Offset is to get the kiln to fire to cone 5-1/2 instead of cone 5. Just add 20 to whatever is set in the cone offset already for cone 5. Then fire to cone 5 and it should be about ½ a cone hotter.