Sentry 2.0
Digital Temperature Controller
Complete Operating Instructions
Cone-Fire (pg 8-11)
From IdLE, press 1.
Available only on ceramic
kilns. Fires to a pyrometric
cone. Enter cone, speed,
pre-heat, hold, and slow cool.
See pages 28-29 for instructions on upgrading your DTC
100, 600, 800 or 1000 series board to the Sentry.
Delay (pg 6)
From IdLE, press 3.
Enter time in hours:minutes.
Delays the start of firing.
Ramp-Hold (pg 12-15)
From IdLE, press 4.
Select stored program (1 - 4).
Enter rate, temperature, and
hold for each segment.
Alarm (pg 6)
From IdLE or during
firing, press 7.
Enter a temperature. When
alarm sounds during firing,
press Enter.
Enter/Start (pg 7)
Press Enter/Start after each
step in programming a firing.
Press Enter/Start once to be
gin the firing.
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Options (pg 17 - 21)
From IdLE, press 0. Press
Enter for option displayed.
Cone-Fire Options
SPd Speed Change the speed
of a Cone-Fire program beyond
the Fast, Medium, or Slow.
OFST Cone Offset Adjust con
troller to a witness cone.
FAN Vent Fan Selects when
the vent fan will operate. (Special
option not on all kilns.)
Standard Options
TCOS Thermocouple Offset
Calibrate the thermocouple
temperature.
CHG- Select °F or °C.
TC Thermocouple Type Se
lect Type K, S or R.
AOP AOP Outlet Select vent
fan or alarm. This is a special op
tion not on all kilns.
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Id Computer ID Select identi
fication number for output to a
computer.
TEdE Temperature Deviation
Set temperature sensitivity of er
ror codes.
SFTY Maximum temp.
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ELEC Electronics Temp.
Check board for overheating.
LOCK Program Lock Make a
program tamper-proof.
CFG Configuration Code
For technicians.
SOFT Software Version
For technicians.
TEST Element Test Diagnos
tics tool for checking elements.
RST Reset Removes cone
and thermocouple offsets, etc.
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Stop/Back (pg 7)
Press during firing or
programming.
Stops a firing. In Options,
takes you back to IdLE.
During programming,
takes you back one step
each time key is pressed.
Multiple Zone Options
DIFF Difference Largest
temperature difference be
tween any two zones.
CAdJ Center Adjustment
Change center heat of some
two-zone kilns.
T123 Zone Tempera
tures Shows temperature of
each zone.
Add Time (pg 6)
During firing, press 2.
Each additional key press
adds five minutes to a hold.
It works in both Ramp-Hold
and Cone-Fire.
Present Status (pg 6)
Press 5 during firing.
Shows the segment that is
currently firing. Works in
both Ramp-Hold and
Cone-Fire.
Program Review (pg 6)
From IdLE or during
firing, press 6.
Shows the program that is
loaded in memory and ready to
fire, or the one that is firing.
Cone Table & Skip
Segment (pg 7)
From IdLE or during
firing, press 9.
From IdLE, shows tempera
ture for the cone you enter.
While Firing: In Ramp-Hold,
skips to the next ramp. In
Cone-Fire, skips out of
Pre-Heat or Hold.
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1
Introduction
Thank you for purchasing the Sentry micro processor, our most advanced generation of digi
tal temperature controllers. The easiest way to learn to operate the Sentry is to sit down in
front of it with these instructions and play with it. Spend time understanding the controller
before you begin to use it.
Damage caused by failure to follow instructions is not covered by warranty.
The Sentry operates in Cone-Fire and Ramp-Hold similar to the earlier DTC 600, 800, and
1000 series. If you are familiar with the earlier controllers, you can follow many of the same
operating procedures with the Sentry.
The Cone-Fire mode applies to ceramics only. If you purchased a heat treating, glass fusing,
enameling or jewelry furnace, your version of the Sentry will include only the Ramp-Hold
mode, not the Cone-Fire. In this case, please disregard “FAST,” “MEDIUM,” “SLOW,”
“Cone Fire” and “Cone #s” on your keypad.
If you purchased the TnF 2 portable controller, you should find a TnF 2 installation
instruction sheet in addition to these instructions.
Instructions for multiple-zone kilns are included in this manual. If you are not sure whether
your kiln is multiple-zone, look into the firing chamber. If you see two or three thermocouple
tips, your kiln is multiple-zone. If you see only one thermocouple, skip multiple-zone
instructions.
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Do not worry if you hear a distinct clicking noise during operation. Mechanical relays click as
they turn the heating elements on and off.
You can connect your Sentry controller to a personal computer, which will allow you to graph
your firings and to monitor them from a distance. Ask for the computer inteface kit, which
consists of a cable, a computer chip for the back of the Sentry, and software for your
computer.
Once you learn the basic features of the Sentry, you will be able to control every stage of firing.
This offers learning opportunities and convenience difficult to imagine with a manual con
trolled kiln.
©2001, by Paragon Industries, Inc. IM-204/5-01
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Contents
Basic Pointers . . . . . . . . . . 4
Which Instructions
Apply to Your Controller . . . . . . . . . . 4
Room Temperature and Humidity. . . 4
Thunder Storms and Power Surges . 4
Display Lights . . . . . . . . . . . . . . . . . . 5
How to Get IdLE to Display . . . . . . . . 5
Firing Completion Message . . . . . . . 5
Repeat Firings . . . . . . . . . . . . . . . . . . 5
Thermocouple Inspection . . . . . . . . . 5
The “LId” Display. . . . . . . . . . . . . . . . 5
The Keys . . . . . . . . . . . . . . . 6
Correcting Entries . . . . . . . . . . . . . . . 6
1 / Cone Fire . . . . . . . . . . . . . . . . . . . 6
2 / Add Time . . . . . . . . . . . . . . . . . . . 6
3 / Delay. . . . . . . . . . . . . . . . . . . . . . . 6
4 / Ramp Hold . . . . . . . . . . . . . . . . . . 6
5 / Present Status . . . . . . . . . . . . . . . 6
6 / Program Review . . . . . . . . . . . . . . 6
7 / Alarm. . . . . . . . . . . . . . . . . . . . . . . 6
9 / Cone Numbers & Skip Segment . 7
Enter/Start . . . . . . . . . . . . . . . . . . . . . 7
The Options Key . . . . . . . . . . . . . . . . 7
The Stop/Back Key . . . . . . . . . . . . . . 7
Cone-Fire . . . . . . . . . . . . . . 8
Standard Schedules
Low Fire Cones 022 - 011. . . . . . . . 9
Middle Fire Cones 010 - 01 . . . . . . 9
High Fire Cones 1 - 10 . . . . . . . . . . 9
Speed (SPd) . . . . . . . . . . . . . . . . . . . 9
Pre-Heat (PRHT) . . . . . . . . . . . . . . . . 9
Hold (HOLd) . . . . . . . . . . . . . . . . . . 10
Cone-Fire Programming . . . . . . . . . 10
Slow Cooling (COOL) . . . . . . . . . . . 11
When the Kiln Shuts Off Too Soon . 11
For Kilns with AOP Outlet . . . . . . . . 11
Ramp-Hold . . . . . . . . . . . . 12
Definition of a Segment . . . . . . . . . . 12
Ramp-Hold Programming . . . . . . . . 13
User Programs (USER) . . . . . . . . . . 13
Firing a Stored User Program . . . . . 14
Rate . . . . . . . . . . . . . . . . . . . . . . . . . 14
Hold (HOLd) . . . . . . . . . . . . . . . . . . 14
AOP Fan. . . . . . . . . . . . . . . . . . . . . . 14
Segments for Controlled Cooling . . 14
Sample Firing Schedules . . . . . . . . 14
Cone-Fire Program Fired in
Ramp-Hold . . . . . . . . . . . . . . . . . . 14
Sculptured Stoneware Bisque
Firing Schedule, Cone 04. . . . . . . 14
Glass Fusing Firing Schedule . . . 15
Glass Slumping Firing Schedule . 15
Starting a Firing in a Hot Kiln. . . . . . 15
When the Kiln Shuts Off Too Soon . 15
Multiple Zone Kilns . . . . . 16
An Overview of Multiple
Zone Firing. . . . . . . . . . . . . . . . . . . . 16
Viewing Zone Temperatures . . . . . . 16
Two Zone Kilns: Adjust Heat in
Center Section (CAdJ). . . . . . . . . . . 16
Thermocouple Failure
In a Multiple Zone Kiln . . . . . . . . . . . 16
Power Output Lights . . . . . . . . . . . . 16
Testing Multiple Zone Elements . . . 16
Options: Cone-Fire. . . . . . 17
Cone-Fire Speed (Spd) . . . . . . . . . . 17
Cone Offset (OFST) . . . . . . . . . . . . . 17
Interpreting Cone Bending . . . . . . 18
When Cone Temperature
Is Off More Than 20°F/11°C . . . . . 18
Fan (FAN) . . . . . . . . . . . . . . . . . . . . 18
Options: General . . . . . . . 18
Thermocouple Offset (TCOS) . . . . . 18
Thermocouple Offset for
Ceramic Firings. . . . . . . . . . . . . . . 18
Calibrating Thermocouple Offset
With a Digital Pyrometer. . . . . . . . 19
Setting Thermocouple Offset . . . . 19
Multiple Zone
Thermocouple Offset . . . . . . . . . . 19
Selecting °F or °C (CHG-) . . . . . . . . 19
°F/°C Temperature
Conversion Formula . . . . . . . . . . . 19
Thermocouple Type (TC) . . . . . . . . 19
AOP Outlet (AOP) . . . . . . . . . . . . . . 20
Computer ID (ID) . . . . . . . . . . . . . . . 20
Temperature Deviation (TEDE) . . . . 20
Maximum Temperature (SFTY) . . . . 20
Electronics Temperture (ELEC). . . . 20
Program Lock (LOCK) . . . . . . . . . . . 20
Configuration Code (CFG) . . . . . . . 21
Software Version (SOFT). . . . . . . . . 21
Element Test (TEST) . . . . . . . . . . . . 21
Reset (RST) . . . . . . . . . . . . . . . . . . . 21
Options: Multiple Zone . . 21
Zone Temperature
Difference (DIFF) . . . . . . . . . . . . . . . 21
Two Zone Kilns: Adjust Heat in
Center Section (CAdJ). . . . . . . . . . . 21
Zone Temperatures (T123) . . . . . . . 21
Error Messages . . . . . . . . 22
FTC / Failed to Cool. . . . . . . . . . . . . 22
FTH / Failed to Heat. . . . . . . . . . . . . 22
LTdE / Low Temperature
Deviation . . . . . . . . . . . . . . . . . . . . . 22
PF / Power Failure . . . . . . . . . . . . . . 22
BAdP / Bad Programming . . . . . . . . 22
ETH / Electronics Too Hot. . . . . . . . 22
FAIL / Thermocouple Failure . . . . . . 22
FTL / Firing Too Long . . . . . . . . . . . 22
HTdE / High Temperature
Deviation . . . . . . . . . . . . . . . . . . . . . 22
PF 2 / Power Failure . . . . . . . . . . . . 22
PF 3 / Power Failure . . . . . . . . . . . . 22
How the Sentry
Handles Power Failures. . . . . . . . . . 23
Using Ceramic Witness Cones
After an Extended Power Failure . 23
PLOG Error Codes. . . . . . . . . . . . . . 23
TCdE / Uneven Multiple
Zone Temperatures . . . . . . . . . . . . . 23
TCR / Thermocouple
Leads Reversed. . . . . . . . . . . . . . . . 23
Appendix A
Display Messages . . . . . . . . . . . . . . 24
Appendix B
Standard Cone-Fire Schedules. . . . 26
Appendix C
Upgrading the DTC 100, 600, 800 &
1000 to the Sentry . . . . . . . . . . . . . . 28
Appendix D
Orton Pyrometric Cone
Temperature Equivalents . . . . . . . . 30
Appendix E
Ramp-Hold Shorthand . . . . . . . . . . 31
Appendix F
Cone-Fire Shorthand . . . . . . . . . . . . 32
3
Safety
Chapter 1
The warranty on your Sentry controller does not cover
damage from overfiring, regardless of the circumstances. It
is the operator’sresponsibility to makesure the kilnturns off
at the end of the firing. Follow these safety rules in addition
to the ones in your kiln or furnace manual.
When the kiln is not in
use, disconnect thepower
and keep the lid or door
closed. (For larger kilns
with heavy cordsets, we
recommend a power dis
connect box near the
kiln.)
Do not leave the kiln unattended, especially
near the expected shut-off time.
Wear firing safety glasses when looking into
peephole of a hot kiln.
Do not touch hot sides of kiln or furnace. Keep
unsupervised children away.
Install your kiln or furnace at least 12 inches
from any wall or combustible surface. (See
manufacturer’s recommendation for your
model.)
Do not open lid or door until kiln or furnace has
cooled and all switches are off.
Fire only in a well-ventilated, covered and pro
tected area away from flammable materials.
Keep cordset away from hot sides of kiln or fur
nace.
DANGEROUS VOLTAGE! Do not touch heat
ing elements with anything. Disconnect kiln or
furnace before servicing.
Do not operate if the controller itself is hotter
than 150°F/66°C. (See instructions on page 20
for checking board temperature.) Never allow
the firing room temperature to exceed
110°F/43°C. (Measure room temperature three
feet from the kiln.)
Stop a firing by pressing the STOP button, not
by disconnecting the power. In certain condi
tions, the controller will interpret a power inter
ruption as a power failure and turn the kiln back
on when you reconnect the power.
Basic Pointers
Which Instructions
Apply to Your Controller
The Sentry fires in two modes:
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Ceramic Cone-Fire, based on pyrometric cones.
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Ramp-Hold, based on custom firing rates and target
temperatures.
Ceramic kilns use both Cone-Fire and Ramp-Hold. Heat
treating, glass fusing, and enameling furnaces and kilns
come with Ramp-Hold only.
1 From IdLE display, press 1.If CONE appears, you
have Cone-Fire mode.If the 1key does not respond,
you have Ramp-Hold mode only.
2 Press STOP to bring the controller back to IdLE .
Note: FAST, MEDIUM, SLOW, CONE-FIRE,
and CONE #s printed on the controller faceplate
apply only to Cone-Fire mode.
If you have Ramp-Hold only, skip pages 8 - 11.
Room Temperature and Humidity
It is okay to store the Sentry at sub-zero temperatures.
But before operating, raise the room temperature to at least
32°F/0°C.
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Note: The Sentry will register sub-zero °F/°Ctem
peratures. However, 32°F/0°C is the lowest recom
mended operating temperature.
The circuit board is rated for 158°F/70°C maximum op
erating temperature. However, the maximum recom
mended temperature is 125°F/52°C. Open windows and ex
haust hot air from the room to lower temperature. (See page
20 to check circuit board temperature.)
High humidity will not adversely affect the Sentry unless
water condenses on the circuit board. Inthis case,do not fire
the kiln until the moisture has evaporated from the board.
Thunder Storms and Power Surges
Unplug the kiln when not in use, especially during thun
der storms and in areas with frequent power surges. If the
kiln is part way through a firing when a storm begins, it may
be okay to continue the firing. When the kiln shuts off, dis
connect the power.
CAUTION: when firing the kiln duringa storm, do
not leave the kiln unattended!
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4
Display Lights
Single Center Light: Time
A lower center dot appears during time display. It sepa
rates hours from minutes (i.e. 1 hour, 30 minutes displays as
01.30). During temperature display, the dot disappears.
Power Output Lights
The Sentry turns on the heating elements intermittently
through relays. The power output lights in the right side of
the display appear when the Sentry sends power to the re
lay(s).
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Single Zone Kiln When the Sentry sends power to the
relays, all three lights appear.
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Two Zone Kiln The top light shows power to the relay
for the top section of the kiln. The bottom light shows
power to the bottom. Ignore the center light.
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Three Zone Kiln The top light indicates power to the
top section relay, the middle light to the middle section,
and the bottom light to the bottom.
°F
°C
Single Right-Hand Light: °C
When temperature is displayed in °C, a light appears in
the lower right. In °F it disappears.
How to Get IdLE to Display
The controller displays IdLE when you first apply power
to the kiln. Operations begin from IdLE . You can’t fire the
kiln until IdLE appears.
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If you press STOP during a firing, AbRT will appear. To
get back to IdLE , press ENTER.
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If the display shows an error message such as FAIL in
stead of IdLE , see pages 22 - 23.
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CPLT (firing completed) appears at the end of a firing.
To make IdLE appear, press any key.
Firing Completion Message
When the firing has completed, four messages will cycle
one after the other:
1 CPLT (complete)
2 Firing time in hours and minutes (amount shown
does not include Cone-Fire slow cooling time)
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3 The temperature the kiln fired to in Cone-Fire, or
the temperature of the last segment in Ramp-Hold
4 The current kiln temperature
Note: If the alarm (see page 6) sounded, and then
the kiln fired to completion, you will see ALAR in
stead of CPLT . Press ENTER. CPLT will appear.
Repeat Firings
To repeat the last firing, press ENTER from IdLE . The
kiln will begin firing. This works in both Cone-Fire and
Ramp-Hold. But first, make sure you are repeating the cor
rect firing by using “Program Review” (see page 6). For re
peat firings that you don’t want to inadvertently change, see
“Program Lock,” page 20.
Thermocouple Inspection
The small rod protruding into the firing chamber is the
temperature sensor, or thermocouple.
CAUTION: Bumping the thermocouple can push
it out of the firing chamber. This could cause an
overfire! The controller does not contain an alarm
to detect this type of failure.
Thermocouples come in different widths. The wider the
thermocouple, the farther it should extend into the firing
chamber. A ¼” diameter thermocouple should extend into
the firing chamberabout 1”. A 1/8”thermocouple should extend into the chamber ½” - 5/8”.
Keep shelves, posts and ware 1” - 1 ½” away from the
thermocouple. Keep an extra thermocouple on hand, espe
cially if you fire hotter than 2000°F/1093°C.
If you are using a portable, separate controller, you will
need to install the thermocouple onto the kiln. See the sepa
rate TnF 2 installation instructions.
The “LId” Display
Reasons LId appears in the display:
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The kiln is equipped with the optional safety switch.
(The switchturns off power to the elements when the lid
or door is open.) LId appearsin thedisplay while the lid
is open during firing.
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On the back of the Sentry circuit board, at the top right
side, is a small two-pin terminal.If the connector on that
terminal is missing, LId will appear in the display dur
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ing firing. The elements will not turn on. (If the two-pin
connector is missing, you can buy another from a com
puter supply store.)
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The safety lid switch is defective or the safety switch wire
is broken.
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5
Chapter 2
The Keys
Correcting Entries
If you enterthe wrong temperature,cone, time, etc.,while
programming, enter 0000. Then enter the correct numbers
before pressing ENTER.See also the Stop/Back Key, page7.
1 / Cone Fire
Cone-Fire is a method of firing ceramics
to a pyrometric cone. See Chapter 3, page 8,
for details. To find out if your Sentry in
cludes Cone-Fire:
1 From IdLE display, press 1.If CONE appears, you
have Cone-Fire mode. If the 1 key does not re
spond, you have Ramp-Hold mode only.
2 Press STOP to bring the controller back to IdLE .
2 / Add Time
This key adds five minutes to a Hold. It is
designed for ceramists who watch witness
cones through the peephole, and for glass
artists who inspect the glass near the end of firing.
1 During a firing, press Add Time. HOLd , and time
in hold, will appear.
2 Press Add Time again. The time shown will in-
crease by 5 minutes. In a few seconds, temperature
display will return.
Note: Add Time will add 5 minutes to Hold in either Cone-Fire or Ramp-Hold, even if no hold had
been programmed. After hold time displays, 5 min
utes are added with each press of the key.
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automatic. The operator assumes full responsibility
for shutting the kiln off at the proper time.
4 / Ramp Hold
Ramp-Hold fires the kiln to the tempera
ture you specify, whereas Cone-Fire fires to
a pyrometric cone. Press 4 from IdLE to
program a firing or to select a stored program. See
“Ramp-Hold,” page 12.
5 / Present Status
Press 5during a firing to display the cur
rent segment that is firing. The messages
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RA 1 Ramp (see page 12), and segment number.
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Hd 1 Hold (see page 12), and segment number.
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PRHT Cone-Fire Pre-Heat (see page 9).
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COOL Cone-Fire Slow Cooling (see page 11).
Uses for Present Status:
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You are firing a program that contains several heating
and cooling segments. Without Present Status, it would
be easy to lose track of which segment is firing.
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In Cone-Fire, you may think the kiln has fired too long
when it is actually only in a slow cooling.
that can appear in Present Status:
6 / Program Review
When you press ENTER to begin firing,
the controller will fire the program that is in
active memory. Program Review shows the
values for thatprogram. The programin active memoryis—
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The program that was fired last, or
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The program that was selected since the last firing.
Start Program Review from IdLE , or while firing, by
pressing 6.
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3 / Delay
This delays the start of the firing by the
amount of time entered. Use it to fit a firing
into your schedule or to take advantage of
lower electric rates at night. Delay zeroes out after each fir
ing. Therefore, it must be programmed for each firing.
1 A Cone-Fire or Ramp-Hold program must be inac
tive memory, ready to fire. (See pages 10 and 13.)
2 From IdLE press 3. Enter delay time (i.e., 5 ½
hours = 05.30). Press ENTER.
3 To begin Delay, press ENTER once from IdLE .A
Delay count-down timer will appear.
Note: Press START during delay to end the delay
and begin the firing. The maximum delay is 99
hours and 59 minutes.
CAUTION: For safety, do not leave the kiln alone
during a delay or a firing. We cannot guarantee your
kiln against overfiring even though the controller is
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Note: In Program Review, Cone-Fire Fast speed
displays as F20. Slow speed displays as S20.
(These speeds are 20% faster and slower than the
standard speed.)
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7 / Alarm
The alarm sounds when the kiln reaches
the alarm temperature you enter. Use the
alarm to alert you to—
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Lower the lid from venting position (ceramics).
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Check the witness cone near shut-off time (ceramics).
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Check the fusing or slumping of glass.
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Remove the knife blade from the furnace at the end of
heat treating.
You can enter only onealarm temperature at a time. How
ever, after the alarm beeps, you can set the alarm for another
temperature, as many times as you want, during the firing.
You can enter a higher or lower temperature than the cur
rent temperature. Enteringan alarm temperature automati
cally erases the previous alarm temperature.
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Setting Alarm From Idle
1 From IdLE , press 7. ALAR will appear alternating
with the last alarm temperature entered.
2 Enter alarm temperature. Press ENTER. IdLE will
appear. (Enter 0000 to turn alarm off.)
Note: 9999, as an alarm temperature, automati
cally changes to the maximum temperature rating
of your controller.
When the alarm sounds, shut it off by pressing any key ex
cept STOP. (The STOP key does not work while an alarm
sounds.) If the alarm soundsas soon as firing begins,it is be
cause the alarm was set to a temperature below the current
temperature.
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Setting Alarm During Firing
1 The alarm beeps while the kiln is firing. Press 7.
2 Enter the new temperature.
3 Press ENTER. The kiln will continue firing.
If you touch 7, enter a new temperature, and forget to
press ENTER, the controller will merely continue firing.
Note: When an alarm sounds, firing to completion
does not shut the alarm off.
9 / Cone Numbers
& Skip Segment
Cone Table
Look up a cone temperature with the 9 key.
1 From IdLE , press 9. CONE will appear, then the
cone, if any, currently programmed in Cone-Fire.
2 Enter a pyrometric cone number. Press ENTER. The
display will show thecone temperature.If you enter a
non-existent cone number, the display will show
CONE , ready for you to enter a different cone num
ber.
Note: Do not be concerned if the actual cone
shut-off temperature does not match the Cone Ta
ble. The temperature of a cone varies with firing
speed. The cone temperatures in Cone Table are
for self-supporting cones fired at a rate of 108°F /
60°C per hour during the last hour of firing.
Skip Segment
Skip Segmentworks only during firing. It jumps from the
current segment to the next one.
To skip a segment, press 9. SKIP will appear, then the
current segment. Press ENTER. (If you change your mind
and don’t wantto skip thatsegment, don’t pressENTER after
SKIP appears. Instead, press 9 again. The firing will con
tinue in the same segment.)
Skip Segment in Cone-Fire
In Cone-Fire, SkipSegment works inPre-Heat and Hold:
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To skip out of Pre-Heat and begin the cone firing.
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To skip out of Cone-Fire Hold. Slow Cooling will begin.
(If the firing does not include Slow Cooling, Skip Seg
ment will notend a Hold.Press STOP toend the firing.)
Skip Segment in Ramp-Hold
In Ramp-Hold, the firing will skip to the ramp of the next
segment from either a ramp or hold of the current segment.
(See page 12 for details on ramps, holds, and segments.)
Skip Segment Examples
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For additional examples, see Chapter 4, pages 14 - 15.
Cone-Fire
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In Cone-Fire you are firing to an 05 witness cone for the
first time. You select cone 04 with a 60 minute hold and a
slow cooling. After 30 minutes in hold, the 05 witness
cone bends to maturity. Use Skip Segment to end the
hold and begin Slow Cooling.
Note: Once you know how much hold time will
bend the witness cone, program that much hold for
the next firing.
Ramp-Hold
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Skipping to a Cooling Segment: You have programmed
2167°F for a cone 5 glaze firing, followed by a segment for
controlled cooling. Watching the witness cone through
the peephole, you notice that cone 5 is bending at 2150°F.
Use Skip Segment to end the firing segment and begin
the one for slow cooling.
Note: Make a note of the temperature at which the
cone bent. Program that temperature for the next
firing.
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Skipping to a Hold: Skip Segment does not skip from a
ramp to a hold. Itskips to the next segment. Ifyou need to
skip to a hold, program an additional segment with the
hold that youwant. Then skipto that segment.Example:
Segment 1: rate 500°F to 1828
Segment 2: rate 200°F to 1750 with 30 minute hold
Enter/Start
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Press ENTER after each step in program
ming a firing.
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Press ENTER once to begin firing.
The Options Key
See Chapter 6, page 17.
The Stop/Back Key
You can stop a firing at any time (except
when the alarm sounds) by pressing STOP.
If you inadvertently enter Ramp-Hold,
Cone-Fire, or Options, you do not have to go through all the
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prompts to get back out. Press STOP to go to IdLE .
The STOP/BACK key is also like the Back button on an
Internet browser. It works in Cone-Fire and Ramp-Hold
programming. It will take you back one step every time you
press the key.
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7
Chapter 3
Cone-Fire
Cone-Fire mode is based on
pyrometric cones. It is not designed for
heat treating, glass fusing and enameling.
For these firings, see “Ramp-Hold,”
page 12. Use Ramp-Hold to fire ceramic
pieces that require a custom firing
schedule, such as some types of stone
ware sculpture or crystalline glaze.
Pyrometric Witness Cones
The Sentryshuts off automatically without cones. Never
theless, every ceramic firing should include at least one wit
ness cone (also called the shelf cone). The witness cone is
the most accurate measurement of heat work in a ceramic
firing.
If you fire the same size load and type of ware regularly,
the witness cones let you compare one firing to the next and
alert you when something is wrong. For example, if the witness cone bends less and less with each consecutive firing,
this may indicate thermocouple temperature drift.
Note: If the bending of the witness cone does not
match the Cone-Fire shut-off, you may want to adjust Cone Offset or Thermocouple Offset. See
pages 17 - 19. If the witness cones bend inconsistently from one firing to another, see “Sentry Troubleshooter,” a separate publication.
How to Position Cones on the Shelf
Position the witness cones
so that you can see them
through a peephole during fir
ing. If thekiln takes longerthan
usual to fire, you may wonder if
something has gone wrong and
the kiln is overfiring. But by
seeing the cones, you will know
how the firing is progressing.
If you follow these guide
lines, you should be able to see
the cones even at cone 10:
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Place the cones 8” - 12” away from a peephole. Posi
tioning them closer makes them difficult to see.
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Have enough space around the cones to keep them from
touching a piece of ware when they bend.
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Position cones so that when viewed from the peephole,
they are silhouetted by an element on the opposite kiln
wall. (Keep cones at least 2” from an element.)
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Use self-supporting witness
cones on the shelf. They stand
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upright without cone holders.
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The element that silhouettes the cones should be level
with the lower part of the cone. If the element is in line
with the upper part of the cone, you won’t be able to see
the cone when it bends.
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If you use the three
cone system, always
have the higher tem
perature cone on the
same side in every fir
ing. Otherwise you can
lose track of which cone
is which.
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Wear firing safety
glasses when viewing
the cones through the
peephole.
See your dealer if in
doubt about which cone number to use with each clay and
glaze.
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Silhouette the lower part of the cone
against an element. Keep the cone 8”
- 12” away from the peephole.
Firing Schedules
Cone-Fire uses three firing schedules:
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Low fire cones 022 - 011
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Medium fire cones 010 - 01
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High fire cones 1 - 10
Should you ever want to customize a Cone-Fire program,
transfer the firing schedule to Ramp-Hold. See Appendix B,
pages 26 - 27.
During a cone firing, press 5 (Present Status) to see
which stage, or segment, of the firing the kiln has reached.
The number displayed will be a segment number from one
of these firing schedules.
Note: Pre-Heat shows inPresent Status as PRHT .
It is not given a separate segment number.
Firing time in each segment is approximate and depends
on the age of elements, voltage, size of load, and the firing
speed you have chosen.
CAUTION: Cone numbers beginning with 0 are
lower in temperature than those without the 0.
When programing a Cone-Fire, be sure you know
the difference between an 05 and 5. See “Tempera
ture Equivalents Chart for Orton Self-Supporting
Pyrometric Cones,” Appendix D, page 30.
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8
Low Fire Cones 022 - 011
This range includes decals, over-decorations, lusters,
and golds.The firing can be fast. Good venting isimportant,
because oils and other organics burn off. Donot closethe lid
from the vented position until all odor has disappeared.
Low Fire Cones 022 - 011 Firing Schedule
Segment Rate Per Hour Time in Segment
1 396°F/220°C 2 hours
2 108°F/60°C 1 hour
Firing time is about 3 to 5 hours, depending on the cone and speed.
High Fire Cones 1 - 10 Firing Schedule
Segment Rate Per Hour Time in Segment
1 324°F/180°C 2 hours, 30 minutes
2 153°F/85°C 35 minutes
3 162°F/90°C 4 hours, 35 minutes
4 108°F/60°C 2 hours
Firing time isabout9 hours, 30 minutes to 11 hours,dependingon the coneand
speed.
Cone-Fire Features
Middle Fire Cones 010 - 01
Use this range for earthenware and commercial low-fire
glazes. Glazes fired on bisque ware (ware that has already
been fired) can be firedfaster than theunfired greenware. In
this cone range,slow firings canproduce poor qualityglazes.
In the following schedule, the firing is slowed during the
silica phase change (1063°F/573°C).
Earthenware and clays that containball clays,talc, and ka
olin will burn off water, carbon, and sulfur. This reduces
weight by 10%.
Cooling too fast can produce glaze pinholes, blisters, and
craters. Unless cooling is slowed near1063°F/573°C, aphysical change in the silica can cause the ware to crack. For this
reason we recommend that you use Cone-Fire’s Slow
Cooling option (see page 11).
We recommend a 10 - 20 minute hold when firing
lead-free glazes.
Middle Fire Cones 010 - 01 Firing Schedule
Segment Rate Per Hour Time in Segment
1 324°F/180°C 2 hours, 30 minutes
2 153°F/85°C 35 minutes
3 180°F/100°C 2 hours, 40 minutes
4 108°F/60°C 1 hour, 30 minutes
Firing time is about 6 to 8 hours, depending on the cone and speed.
High Fire Cones1-10
This is the firing range for porcelain and stoneware.
These bodies fire nearly to vitrification and can shrink up to
16%. Water, carbon and sulfur burn out during the early
stages and must be vented. The amount of oxygen in the kiln
affects the color of the fired clay. The high fire schedule be
low slows down during the last 210°F/100°C to produce
better density in the ware.
Typical porcelain clays are formulated from kaolin, feld
spars, silica and ball clays. Weight loss is 10 - 12% and
shrinkage is as high as 20%. If overfired, porcelain may warp
or blister. Cone-fire’s Hold option usually enhances porce
lain.
Speed (SPd)
The Cone-Fire schedules shown on this page are stan
dard. When you select Medium speed in a Cone-Fire pro
gram, the kiln uses these standard firing schedules. When
you select Fast (1), the standard schedule fires 20% faster.
On Slow (3), it fires 20% slower.
You can alsoalter the firing speedeven more under Speed
(Spd) in Options. See page 17.
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Pre-Heat (PRHT)
Moist greenware canexplode during firing. Thishappens
when the moisture in the clay turns to steamrapidly and cannot escape fast enough. The Sentry Pre-Heat feature dries
the ware at low temperature before the moisture can turn to
steam.
Pre-Heat is sometimes necessary when firing thick
greenware, such as stoneware. It may also be necessary in
humid weather, which inhibits drying. If possible, however,
avoid using Pre-Heat to dry greenware. If the greenware
feels damp or cool whenyou touch it to yourcheek, dry it longer before firing. Use a dehumidifier in humid weather.
Drying greenware in the kiln tends to rust the kiln.
Note: During Pre-Heat, ventthe lid. Otherwisethe
firebricks will absorb moisture, leading to rust be
hind the steel case. Moisture in the firebrick can
also slow the firing to a crawl.
CAUTION: Venting the lid during Pre-Heat is so
important that some ceramists use the extended
vent position or even leave the lid open. If you do
this, you must be near your kiln at the end of
Pre-Heat to lower the lid.
Pre-Heat raises the temperature 60°F/33°C per hour to
200°F/93°C. Then it holds at 200°F/93°C for the time you
specify. Pre-Heat works in Cone-Fireonly. After Pre-Heat is
finished, the kiln will automatically begin firing to the cone
you have selected.
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Note: At high altitude, water boils at a lower tem
perature. This may cause moisture in the ware to
turn to steam even during Pre-Heat.
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9
Cone-Fire Programming
Use these instructions for your first firings. Later
you may prefer “Cone-Fire Shorthand Pro
gramming,” page 32.
As the Sentry prompts for cone, speed, pre-heat,
hold, and slowcooling, values enteredfor the lastfiring
will appear. To use these values again, press ENTER.
To fire without Delay or Alarm: Follow steps 1
through 7 below. Then from IdLE press START.To
use Delay or Alarm, see also page 6.
1 Apply power to the kiln. 8888 then IdLE
will appear. (Press ENTER if IdLE does not
appear.)
2 Press 1. CONE will appear. Enter cone num
ber. (If the 1 key does not respond, your con
troller uses Ramp-Hold only.)
3 Press ENTER. SPd will appear. Enter speed:
FAST (1), MEDIUM (2), SLOW (3). (Me
dium speed will display as Std .)
4 Press ENTER. PRHT will appear. To use
Pre-Heat, enter time. Otherwise enter 0.
5 Press ENTER. HOLd will appear.To soak the
ware at the end of firing, enter a hold time.
Otherwise enter 0.
6 Press ENTER. COOL will appear. To use
Slow Cooling, enter cooling rate as degrees
per hour. (180°F/82°C is maximum rate.
Press 0 to turn Slow Cooling off.)
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Mirror Test
This test will help you de
termine how much Pre-Heat
to use. Occasionally during
Pre-Heat, hold a mirror near
the top peephole. (Be careful
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to avoid burns.) The mirror
must be at room tempera
ture, not hot, so hold it near
the peephole for only several
seconds.
If the mirror fogs, mois
Vent the kiln until moisture no lon
ger fogs a mirror.
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ture is still escaping fromthe
ware. When the mirror no longer fogs, you can exit Pre-Heat
and begin the firing.
To interrupt Pre-Heat and begin firing to the cone in
Cone-Fire, press 9 (Skip Segment). SKIP , alternating with
1 , will appear. Press ENTER. Segment 1 of the firing will
now begin. (See Cone-Fire firing schedules, page 9.)
Note: If you are using a vent fan, such as the Orton
KilnVent, turn the fan on during Pre-Heat. The fan
will help to remove moisture. (AOP Fan users: see
the Fan option, page 18.)
How to Use Pre-Heat When Kiln is Above
200°F/93°C at Beginning of Firing
If you begin firing with Pre-Heat in a kiln that is already
hotter than Pre-Heat temperature, the kiln will skip
Pre-Heat and begin firing to the cone. There aretwo ways to
use Pre-Heat in this situation:
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Wait until the kiln cools below 200°F before starting the
firing. This is the preferred method.
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Load the kiln and start the firing, but include enough
time in Delay for the kiln to cool below 200°F before
Pre-Heat begins.
7 Press ENTER. IdLE will appear.
8 To set Alarm:Press 7. ALAR will appear. En
ter alarm temperature. (Press 0to turn alarm
off.) Then press ENTER.
9 To set Delay: Press 3. dELA will appear. En
ter delay time. Press ENTER. (Delay zeroes
out after each firing.)
10 To start program, press ENTER once.
STRT will appear, then temperature. If
Delay was programmed, DELA will appear,
then time remaining until start. To stop the
program during firing, press STOP.
When program fires to completion, CPLT will ap
pear. Press ENTER. IdLE will appear. To shut off the
alarm when it sounds during a firing, press ENTER.
10
Hold (HOLd)
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Cone-Fire Hold heat-soaksthe ware at thecone tempera
ture at the end of the firing. Without Hold, the kiln shuts off
after it reaches the cone temperature. Hold maintains the
cone temperature forthe period you specify.Hold helps even
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out the temperature throughout the kiln. It also helps the
heat to penetrate completely into the clay. (Rapid firing is
like cooking: the turkey will be done on the outside but not
on the inside.) Hold helps glaze absorb china paint. It helps
to heal glaze defects such as bubbles. A little hold time can
yield dramatic results.
CAUTION: Too much hold time can overfire your
ware and burn out colors.
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One way to add Hold time without over-firing is to fire to
one cone cooler than needed. Then add enough hold time to
bend the next hotter cone. Hold time needed to bend the
next cone will vary. As a rule of thumb, 45 - 60 minutes of
hold = one cone of heat work.
Example: to fire to cone 05, program Cone-Fire for 06
and add 45-60 minutes of hold time.
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