The diagram at the bottom of the previous page shows
three rates. A rate of 1000° per hour will reach 1000° in 1
hour. A rate of 500° will reach 1000° in 2 hours. A rate of
333° will reach 1000° in 3 hours.
If you want the kiln to fire at full speed, enter a rate of
9999. See step 3, inside the red box on the previous page.
Note:
In Program Review, a heating rate of 9999 is
displayed as
[FULL]
. When a kiln is heated at full
power, it may overshoot the target temperature,
especially in the lower range. To avoid this, add an
extra segment with a slower rate for the last 50 de-
grees of temperature 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. See TEDE, Temperature Devia-
tion, and HTDE, High Temperature Deviation,
page 24.
If you are not sure how fast to fire, remember an old fir-
ing adage: When in doubt, slow it down.
Note:
In the Rate option, page 23, you can set up
your controller to calculate rate in one of three
ways: 1) degrees of 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 hav-
ing problems entering rate, check the RATE op-
tion to be sure your controller is set for degrees per
hour.
Rate as Time Needed to Reach the
Target Temperature
After selecting
[TIME]
in the RATE option, program
the amount of time that each segment should take to reach
its target temperature. For example, 1 hour and 30 minutes
is programmed in Rate as 01.30.
The Time mode in some ways is different and opposite
the standard degrees-per-hour rate explained above:
I
For a Full rate, or the fastest that the kiln will fire, select
a time rate of 00.00.
I
After you have entered all of the segments for your pro-
gram, you will need to zero out the remaining available
segments. To do this, select a rate of 99.00 hours.
Hold (HD #)
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 helps even out the temperature through-
out the kiln. Hold can be used in either heating or cooling
segments.
In programming step 5, previous page, enter the hold
time. When hold is set to 99.99 hours, the Sentry will remain
at that temperature indefinitely until you press
STOP
.
Ceramics:
Watch the pyrometric witness cones
through a peephole. Press
STOP
when the correct witness
cone bends, noting how much Hold time was needed. Pro-
gram that much Hold time the next time you fire the same
type of ware. (During Hold, the temperature will alternate
with time left in Hold. Subtract that amount from the total
Hold time entered.)
AOP: Turn on a Fan, Light, or Alarm
The AOP (auxiliary output) is an optional receptacle, or
socket, mounted on the kiln. Plug a kiln vent, light, or bell
into the receptacle, and use your controller to turn the re-
ceptacle on or off for each segment.
If your kiln has the AOP receptacle and you want to use
it, see the AOP1, AOP2 option on page 22. Follow the in-
structions to activate the AOP.
During programming,
[FN]
will appear for each seg-
ment (
[FN 1] [FN 2] [FN 3]
etc.). Use the 1 and 2 keys to se-
lect On or Off for each segment.
[FN]
will appear only if the
AOP has been activated in the AOP1 or AOP2 Option.
Programming a Cooling Segment
For controlled cooling, program a segment to a lower
target temperature than that of the previous 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.
Pointer:
If you prop the lid or door of the kiln for a
fast cooling, program a fast cooling rate for that
segment. If you lower the temperature 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 the glass 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 open the door all
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, pro-
gram a crash cooling rate of 9999. This turns off
TEDE error codes only for that particular seg-
ment. The TEDE codes still work on the hold and
the other segments.
16
Cone-Fire / Ramp-Hold
Do not leave your kiln unattended during operation.
