Operating instructions
Note: In Program Review, a heating rate of 9999 is
displayed as . When a kiln is heated at full
power, it may overshoot the target temperature, espe
-
cially in the lower range. To avoid this, add an extra
segment with a slower rate for the last 50 degrees of
temperature rise.
CAUTION: The Sentry includes error messages to
warn you when the kiln is at the wrong temperature.
Firing the kiln at full rate turns off some of these warn
-
ings. See TEdE, Temperature Deviation, page 24, and
HTdE, High Temperature Deviation, page 27.
If you are not sure how fast to fire, remember an old fir
-
ing adage: When in doubt, slow it down.
Note: At the time that you purchasethe controller, the
factory can set up your controller to calculate rate in
oneof three ways: 1) degreesof temperature change per
hour 2) degrees of temperature change per minute, or
3) elapsed time needed to reach a temperature. The
normal setting is degrees per hour. If you are having
problems entering rate, check the RATE option to be
sure your controller isset for degrees per hour,page 23.
(This note applies only to 18D and later software ver
-
sions. All pre-18D controllers figure rate only as de-
grees per hour. See page 25, SOFT option, to look up
software version.)
Hold (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 gives the temperature time to become
more even throughout the kiln. Hold can be used in either
heating-up or cooling-down segments.
Wearing firing safety glasses,
watch the witness conenear the end ofthe fir
-
ing. (See page 10.) When the witness cone
bends, note the hold time. The next time you
fire the same type of ware loaded to the same
capacity, program that amount of hold time.
Note: When the Sentry is in hold during a
firing, the display will alternate between
time left in holdand the temperature. To fig
-
ure hold timeneeded for thenext firing,sub
-
tract time left in hold from total hold time
entered.
In programming step 5, page 15, enter
hold time. When hold is set to 99.99 hours, the Sentry will
remain at that temperature indefinitely until you press
.
AOP Fan
The optional AOP (auxiliary output) is a special-order
electricreceptaclemounted in the kiln’sswitch box.This re
-
ceptacle can power a kiln vent or external alarm. (See Op
-
tions, page 22.) During programming, will appear for
eachsegment ( etc.).Use the 1 and2 keys
to select On orOff for eachsegment. will appear only
if the AOP has been activated in the AOP Option.
Programming a Cooling Segment
For controlled cooling, program a segment to a lower
target temperature than that of the preceding segment.
Example: You fire at a rate of 500°F per hour to 1450°F
with your first segment. Then you want the kiln to cool at a
rate of 100°F per hour down to 700°F. Here is how you
would program the two segments:
Rate Temp.
Segment °F/°C °F/°C Hold
1 500 / 277 1450 / 788 00.00
2 100 / 55 700 / 371 00.00
The first segment is the heating segment. The second
one is the cooling segment. The controller does not use mi
-
nus numbers for cooling. Just enter a lower target tempera
-
ture than that of the previous segment.
If you prop the lid or door for a fast cooling, program a
fast cooling rate for that segment. If you lower the tempera
-
ture quickly by propping the lid but program a slow cooling
rate, the controller will just raise the temperature again.
Example: Some glass artists flash-cool theglass just after
it fuses. They open the door a few inches 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. This shuts off the heating elements dur-
ing that segment, allowing the kiln to cool rapidly.
Note: During fast cooling, do not openthe doorall the
way. Do not force-cool the kiln with a fan.
Note: See Temperature Deviation (TEdE),
page 24, for information on error codes that
may appear during “crash” cooling. To turn
these codes off, program a crash cooling rate
of 9999. This turns off TEdE error codes only
for that particular segment. The TEdE codes
still work on thehold and the othersegments.
Suppose you enter a cooling rate that is
faster than the kiln can cool? Depending on
the rate you enter, you may get an alarm mes
-
sage. (Press to turn off the alarm.)
Temperature Overshoot
When a kiln is heated too fast, it may overshoot the tar
-
get temperature, especially in small kilns at lower tempera
-
tures. To avoid this, add an extra segment to slow the firing.
The segment with the slower rate should begin approxi
-
mately 40° - 60° below the final target temperature.
A Practice Program
To practice using the controller, we will enter a program
that includes three segments. The last segment is a cooling
segment.
16 Cone-Fire / Ramp-Hold
“Rate” is how
many degrees per
hour the kiln will
climb in temper
-
ature. (Or how
fast it cools
during a con
-
trolled cooling.)