Sentry Industries Sentry 2.0 - Manual (Page 14)

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 ENTERto 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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