Page
ST312
User
Handbook
12
Operating Notes
If the ST312 is programmed to heat the kiln at a faster rate than the kiln is
capable of then the ST312 will turn on full power then wait until the kiln
temperature has risen to the correct temperature before proceeding to the
next ramp or soak segment.
Likewise if the ST312 is programmed to cool the kiln at a faster rate than
the kiln is capable of then the ST312 will apply zero power then wait until
the kiln has cooled to the correct temperature before proceeding to the
next ramp or soak segment.
Kiln too slow
Heating & Cooling Ramps
The ST312 is capable of controlled ramps for both heating and cooling. If
the soak temperature is set lower than t1 for example then ramp 2 will
automatically become a
negative
(cooling) ramp.
STOP key operation
If the START/STOP key is pressed during a firing then the firing will be
halted (not paused). Pressing the START/STOP key again will cause the
ST312 to restart the firing from the beginning. The ST312 will look at the
current kiln temperature and if this is greater than temperature t1 then the
ST312 will automatically
cool
from current temperature to t1 at ramp rate
1. This may not be what is desired so the STOP key should only be used
to halt the firing in an emergency.
The program can be paused or program data can be changed while the
controller is firing (see page 14). This is a better option than using the
STOP key. The segment advance feature (see page 14) is however avail-
able to recover quickly from STOP key operation if required.
Memory
All programs & necessary data are remembered when the ST312 is turned
off. In the event of power failure during firing the ST312 will automatically
resume firing when power is returned (this feature can be disabled: see in-
stallation handbook).
Firing
Delayed Start
The delayed start time period is set to
00
.
00
when the ST312 is turned on.
ST312 User Handbook
Page 9
Firing
To start a firing press the START/STOP key. The RUN lamp will light.
To stop the firing prematurely press the START/STOP key again.
.
20
°C
°C/hr
hr.min
If the left-hand decimal point is on then
the keyboard is locked & the ST312
will not respond to the START/STOP
key. Press the
©
&
ª
keys together &
hold down for 5 seconds to unlock.
01
.
12
°C
°C/hr
hr.min
If a delayed start has been set then press-
ing the START/STOP key causes a time
delay to start. The time remaining is
shown on the display—this counts down
once per minute. The DELAYED
START lamp on the mimic panel will
light. The centre decimal point will flash
once per second.
20
.
°C
°C/hr
hr.min
If no delayed start has been set (00.00)
then pressing the START/STOP key
causes firing to commence immedi-
ately. The RAMP 1 lamp on the mimic
panel will light. If kiln heating is re-
quired then the right-hand decimal
point on the display will light while
heating power is being applied to the
kiln.
Information: The ST312 operates by calculating the amount of energy required
by the kiln every 30 seconds. If for example 40% of full energy is required to
maintain a particular ramp rate or a particular soak temperature then the
ST312 will apply heating power to the kiln for 12 seconds every 30 seconds. The
right-hand decimal point in the display will light for 12 seconds every 30
seconds. If the kiln has a contactor then a loud click will be heard both when
the decimal point lights up and when it goes out. If full heating power is
required then the decimal point will remain lit. If full cooling is required then
the decimal point will remain off.
Firing
Hint: it is good practice to check that the program is correct by pressing
the
¨
key & checking the program contents before pressing the START/
STOP key to start a firing.
