Sentry Industries Sentry 2.0 Firing a Stored User Program, Rate, AOP Fan, Sample Firing Schedules

Firing a Stored User Program

To use a stored program, press 4 from IdLE. Enter the program number at the USER prompt. Press ENTER. If there are no changes to the program, press STOP. IdLE will appear. The controller is ready to fire your selected program. To begin firing, press ENTER once. (Use “Program Re- view,” page 6, before firing. See also “Repeat Firings,” page 5.)

Rate

As stated before, each segment must include a rate, pro- grammed as degrees of temperature change per hour.

The kiln will fire at full power when the rate is 1799°F/999°C or higher. Programming a rate of 9999 is the easiest way to program a maximum rate.

Note: In Program Review, 9999 is displayed as FULL . When a kiln is heated at full power, it may over-shoot the target temperature, especially in the lower range. To avoid this, add an extra segment with a slower rate for the last 20 degrees of tempera- ture rise.

CAUTION: The Sentry includes error messages to warn you when the kiln is at the wrong tempera- ture. Firing the kiln at full rate turns off some of these warnings. For details, see “Temperature De- viation,” page 20.

If you are not sure how fast to fire, remember an old firing adage: “When in doubt, slow it down.”

Hold (HOLd)

Hold maintains the temperature of a segment for the time you specify. Hold gives the temperature time to become more even throughout the kiln. Hold can be used in either heating up or cooling down segments.

Ceramics: Wearing firing safety glasses, watch the wit- ness cone near the end of the firing. (See page 8.) When the witness cone bends, note the hold time. The next time you fire the same type of ware loaded to the same capacity, pro- gram that amount of hold time.

Note: During Hold, the display temperature will alternate with time left in Hold. To figure hold time needed for the next firing, subtract time left in Hold from total Hold time entered.

When Hold is set to 99.99 hours, the Sentry will remain at that temperature indefinitely, until STOP is pressed.

AOP Fan

The optional AOP (auxiliary output) is a special-order electrical receptacle mounted in the kiln’s switch box. This receptacle can power a kiln vent or external alarm. (See Op- tions, page 20.) In Ramp-Hold, the prompt for the AOP out- let is FN , which can be turned on or off for each segment.

Segments for Controlled Cooling

For controlled cooling, program a segment to a lower temperature than that of the preceding segment.

If you prop the lid for a fast cooling, program a fast cooling rate. If you program a slow cooling rate, but lower the tem- perature quickly by propping the lid, the controller will de- feat your fast cooling. It will raise the temperature again.

Glass fusers sometimes flash-cool the glass at the end of fusing. They lift the lid slightly to remove heat, then close it again. This takes the glass down rapidly through the devitrification range. To program a flash-cool, use a rate of 9999.

Suppose you enter a cooling rate that is faster than the kiln is able to cool? Depending on the rate you enter, you may get an alarm message. (Press ENTER to turn off the alarm.)

The controller, of course, cannot speed cooling beyond the kiln’s natural cooling rate.

Note: During fast cooling, do not open the lid /door all the way. Do not force-cool the kiln with a fan.

Sample Firing Schedules

These sample firing schedules illustrate different ways to use your Sentry. When designing a firing schedule for mate- rials you are unfamiliar with, or when using one of these schedules, test-fire samples first.

Cone-Fire Program Fired in Ramp-Hold

The following firing schedule is the cone 04 Cone-Fire schedule at standard (medium) speed. (See pages 26 - 27.) A slow-cooling segment was added.

	Rate	Temp.
Segment	°F/°C	°F/°C	Hold
1	324/180	1022/550	00.00
2	153/85	1112/600	00.00
3	180/100	1837/1003	00.00
4	108/60	1945/1063	00.00
5	150/83	1000/537	00.00

In this schedule, the kiln will cool at 150°F/83°C per hour to 1000°F/537°C. Some ceramists use slow cooling with cer- tain glazes.

Sculptured Stoneware Bisque

Firing Schedule, Cone 04

Rate	Temp.
Segment	°F/°C	°F/°C	Hold
1	60/33	200/93	03.00
2	80/44	700/371	02.00
3	80/44	1100/593	00.00
4	108/60	1945/1062	00.00
5	150/83	1400/760	00.00

This slow firing is for thick stoneware. Change the target temperature in segment 4 when firing to a different pyro- metric cone. The ware should be bone dry. Test samples un- til you are sure the schedule works for your clay.

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