Theory of
Operation
The temperature you are firing to is called the target temperature. After the controller reaches the target tem- perature, it can also hold that temperature.
The controller fires at a controlled heating rate. The rate is figured in degrees per hour. If you selected a rate of 100° per hour, it would take 10 hours for the kiln to reach 1000°. Rate is similar to “miles per hour.”
In summary, the controller does three basic tasks:
1)It fires at a controlled heating rate, or speed, mea- sured in degrees of temperature change per hour.
2)It fires to a target temperature.
3)It can hold the target temperature.
The controller fires in segments, or stages. A segment is a given heating rate to a target temperature. Shown above is a segment with a rate of 625° per hour, a target temperature of 1250°, and a hold of one hour.
Heating rate is figured in degrees per hour. The recom- mended heating rate for the material you are firing is usu- ally available from your supplier. It also varies depending on the thickness of the material.
To figure how long a firing segment will take, subtract the current temperature from the target temperature and divide the resultant temperature by the heating rate. In the diagram above, the firing time is 1250° - 80° (room tempera- ture) = 1170 ÷625 = 1.87 hours.
The controller can fire up to 8 segments per firing. One segment is often all that is needed, though.
After the controller has finished firing the last segment, it will turn off power to the elements.
Note: If you enter a rate of 0000 in segment 1, or if the target temperature in segment 1 is lower than the cur-
rent temperature, 
will appear in the display.
Rate
Each segment must include a rate, which is degrees of temperature change per hour.
The kiln will fire at full power when the rate is
1799°F/999°C. Full power displays as 
.
Note: To enter full power from |
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Hold
Hold is the length of time that you want the kiln to re- main at the target temperature. Hold is also called soak or dwell time. Hold maintains a steady temperature for the length of time you specify. You can use Hold in both heat-
When Hold is set to 99.59 hours, the controller will re- main at that temperature indefinitely, until you press
. To enter a 99.59 hour Hold, press the 
once from 00.00 during programming.
Note: During a Hold, the display flashes between the Hold temperature and time left in Hold.
Two Firing Modes: Single-Speed and Ramp-Hold
To give you greater flexibility, your controller has two firing modes:
Single-Speed Mode (see next page)
Often times, all you will need is
In
Ramp-Hold Mode (see page 7)
5