Sentry Industries Sentry 2.0 General Options, Fan FAN, Thermocouple Offset Tcos

■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.

2Press ENTER. The current Cone Offset adjustment number will appear.

3Using 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.)

1From IdLE , press OPTIONSrepeatedly until FAN appears.

2Press 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.

3After 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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