How the Sentry
Handles Power Failures
The Sentry handles a power failure in two ways:
1After a brief power failure, the controller continues firing as before. It shows a normal temperature dis- play alternating with PF .
2After an extended power failure, PF 2 or PF 3 will appear. The kiln will NOT resume firing.
The controller will resume the firing after a brief power failure provided these conditions are met:
■The temperature must be above 212°F/100°C when the power comes back on.
■A
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When the Sentry aborts a firing after a power failure, the display will show the following:
■PF 2 or PF 3
■Total firing time before power failed
■Temperature at the time of power failure
■Current kiln temperature
To resume firing, press ENTER. The kiln will begin firing again from its present temperature. For example, the kiln reached 1000°F/538°C when power failed. The temperature is 800°F/426°C when you turn the kiln back on. Firing will re- sume from 800°F/426°C. You need not cool the kiln to room temperature before starting a ceramic firing over unless you decide to use new witness cones.
When you resume firing by pressing ENTER, the control- ler begins firing in the first segment with a temperature higher than the current kiln temperature. However, if the power failed during a ramping down (cooling) segment, the controller will resume firing from the same cooling segment.
Using Ceramic Shelf Cones After an Extended Power Failure
■The firing was interrupted more than 100°F/56°C from the terminal temperature: Fire the ware again. It is okay to use the same partially fired witness cones, even if they cooled back down to room temperature. So long as the cones did not heat to within 100°F/56°C of ma- turity, they can be used again.
■The firing was interrupted less than 100°F/56°C from the terminal temperature: Fire the ware again. If the kiln shuts off within 100°F/55°C of maturity, and the temperature drops 50°F/28°C or more after the kiln shuts off, do not depend on the witness cones. Once they cool 50°F/28°C after they have been heated to within 100°F/55°C of maturity, they will not bend properly. This is because they form a hard shell.
PLOG Error Codes
A PLOG error code means that the controller failed a
PLOG 3 / Memory Corruption
Resets the Sentry to factory default settings.
PLOG 4 / Configuration Corruption
Return the Sentry to the factory after a PLOG 4 code.
PLOG 5 / Firmware Problem
PLOG 6 / Software Problem
PLOG 7, 8, 9 /
PLOG 11 / Bad Thermocouple Signal for 60 seconds
Clearing a PLOG 11 Error Code
PLOG 11 indicates that a thermocouple is about to fail or that electrical noise is affecting the thermocouple.
■Try moving the thermocouple lead wires away from nearby electrical wires and relays.
■Make sure the bare part of the leads extending from the thermocouple are not touching the kiln case.
■Replacing the thermocouple usually clears the PLOG 11 code.
Clearing the Other PLOG Error Codes
■Clear the PLOG error code by pressing ENTER.
■If pressing ENTER does not clear a PLOG error, turn off power to the kiln for 10 seconds. Repeat if necessary.
After a PLOG error clears, it is okay to fire the kiln again.
TCdE / Uneven Multiple
Zone Temperatures
On a multiple zone kiln, TCdE usually means the thermocouples and elements are improperly wired. A ther- mocouple is turning on the elements to the wrong zone. For instance, if the top thermocouple turns on the bottom ele- ments, the kiln will fire out of balance. When zones are out of balance by 140°F/60°C, TCdE will appear in the display.
Visually compare the wiring of the thermocouples, relays and elements of your kiln to the kiln’s wiring diagram. Also, use the Element Test option shown on page 21.
TCR / Thermocouple Leads Reversed
Check that the thermocouple lead wires are connected to the correct terminals. See your wiring diagram.
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