Sentry Industries Sentry 2.0 - Manual (Page 18)

■ Place witness cones in several locations in the kiln.
How to Use Cone Offset
Cone Offset changes the shut-off point of the cone by the
degrees of temperature shown in the chart below.
1 From IdLE , press OPTIONSuntil OFST appears.
2 Press ENTER. The current Cone Offset adjustment
number will appear.
3 Using the 1 and 2 keys, select a new adjustment
number (see chart below). Then press ENTER.
OFST will appear. To return to IdLE , press
STOP.
Cone Offset Settings
Note: select a cone in Cone-Fire before changing Cone Offset.
°F Setting °C Setting Result
0 0 No adjustment
5 3 Kiln will fire hotter
10 6 Kiln will fire hotter
15 8 Kiln will fire hotter
20 11 Kiln will fire hotter
-5 -3 Kiln will fire cooler
-10 -6 Kiln will fire cooler
-15 -8 Kiln will fire cooler
-20 -11 Kiln will fire cooler
Cone Offsets remain in memory for future firings unless
you use the Reset option (page 21).
Interpreting Cone Bending
Position the witness cone in the kiln according to instruc-
tions on page 8.
The cone bent to 6 o’clock:
No calibration in Cone Offset
needed. The self-supporting cone
has fired to maturity when the tip is
even with the base as shown.
The cone did not bend far
enough: Use a positive Cone Off-
set number for a hotter firing, such
as 20 (°F).
The cone bent too far: Use a
negative Cone Offset for a cooler
firing, such as -20 (°F).
Note: Do not be overly concerned with achieving
an exact 6 o’clock bend. The difference between a 3
o’clock and a 6 o’clock bend is only a few degrees.
When Cone Temperature
Is Off More Than 20°F/11°C
The maximum amount that Cone Offset can change the
temperature is 20°F/11°C. When the temperature is off more
than that amount, correct with Thermocouple Offset.
Fan (FAN)
Control the Optional AOP Receptacle in Cone-Fire
The AOP (auxiliary output) is a special-order kiln switch
box receptacle. The Sentry controls power to the AOP recep-
tacle. The AOP is usually used to power a kiln vent. The Fan
option determines when an AOP-powered kiln vent will turn
on during Cone-Fire.
Before the Fan option will appear on the Options list, (1)
you must enter a Cone-Fire program in active memory and
(2) you must select FAN3 in the AOP option. (See page 20
for instructions on selecting FAN3 in the AOP option.)
1 From IdLE , press OPTIONSrepeatedly until FAN
appears.
2 Press ENTER. Use the 1 and 2 keys to select one of
these settings:
■ ON The vent is on during Pre-Heat, the cone firing,
and Slow Cooling. It turns off at 212°F/100°C.
■ OPT The vent is on during Pre-Heat and the cone fir-
ing. Then it shuts off. (It is off during Slow Cooling.)
■ OFF The vent is off all the time.
3 After selecting one of the above, press ENTER.
Press STOP to return to IdLE .
General Options
General options are available on all Sentry controllers.
Thermocouple Offset (TCOS)
Calibrate the Thermocouple(s)
The thermocouple is the rod protruding into the firing
chamber. It measures temperature. Thermocouples can
“drift” as they age, causing a shift in temperature readings.
Thermocouple Offset calibrates the controller to compen-
sate for drift.
Note: The thermocouple must protrude into the
firing chamber the correct distance: 1” for ¼”wide
thermocouples, 1
2
" - 5
8
" for 1/8” wide
thermocouples.
Thermocouple Offset for Ceramic Firings
In ceramics, Cone Offset (see page 17) adjusts only one
range of pyrometric cones without affecting the other cones.
Thermocouple Offset, on the other hand, affects all cones,
and all Ramp-Hold firings, equally. A 5° hotter setting in
Thermocouple Offset fires everything 5º hotter.
Note: If you find that all your cones are consistently
under- or over-firing, adjust Thermocouple Offset.
If you need to adjust only a particular cone, use
Cone Offset.
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