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Page 

     ST312A 

User 

Handbook 

12 

Operating Notes 

If the ST312A is programmed to heat the kiln at a faster rate than the kiln 
is capable of then the ST312A 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 ST312A is programmed to cool the kiln at a faster rate 
than the kiln is capable of then the ST312A 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 ST312A 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 ST312A will look at 
the current kiln temperature and if this is greater than temperature t1 then 
the ST312A 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 ST312A is 
turned off.  In the event of power failure during firing the ST312A will 
automatically resume firing when power is returned (this feature can be 
disabled: see installation handbook). 

Firing 

Delayed Start 

The delayed start time period is set to 

00

.

00

 when the ST312A is turned on. 

ST312A 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 ST312A 
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 immediately.  
The RAMP 1 lamp on the mimic panel 
will light.  If kiln heating is required then 
the right-hand decimal point on the dis-
play will light while heating power is 
being applied to the kiln. 

Information: The ST312A 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 ST312A 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. 

Summary of Contents for ST312A

Page 1: ...df ST312A User Handbook Page 1 ST312A User Handbook ST312A Temperature Programmer TAFFOR S D Stafford Instruments Ltd Tel 44 0 1785 255588 Fax 44 0 1785 255589 www staffordinstruments co uk email support stafford inst co uk Issue 2 00 Date 01 June 2009 See separate handbook for User Instructions Copyright 2009 Stafford Instruments Ltd ...

Page 2: ...0 30 Earthenware Mid Temperature Glaze 90 C hr 600 C 00 30 Earthenware High Temperature Glaze 90 C hr 600 C 00 30 Stoneware Glaze 90 C hr 600 C 00 30 On Glaze Enamel 90 C hr 600 C 00 30 Heavy Sculpture 50 C hr 300 C 00 30 Lustre 90 C hr 600 C 00 00 Ramp 2 FULL FULL FULL FULL FULL FULL FULL FULL 70 C hr FULL Soak temp 960 C 1000 C 1160 C 960 C 1040 C 1140 C 1250 C 780 C 1000 C 750 C Sample Programs...

Page 3: ...t locked Press and hold in both the ª keys for 5 seconds to lock the ST312A Power Failure Recovery If power fails during firing then the ST312A recovers as follows For power failure during start delay the ST312A commences firing immedi ately when power returns For power failure during ramp 1 or ramp 2 the ST312A goes back into the ramp it was previously executing For power failure during soaking t...

Page 4: ... to terminate the firing with all the keys locked An alarm buzzer sounds once per second SWITCH KILN OFF To reset the ST312A turn off the power to the instrument and have the fault investigated by your installer or kiln service engineer to rectify the fault Technical note any error message will cause the auxiliary alarm relay if fitted to open see installation handbook for details Note these error...

Page 5: ...hours limit Err6 C C hr hr min Possible causes are contactor failure or thermocouple connection intermittent or high resistance ST312A User Handbook Page 5 Turning On F1 04 tC r tC S tC n tC K 8 8 8 8 When turned on the ST312A performs a display test by briefly illuminating all of the display digits and all of the front panel lamps The version number of the software embedded within the ST312A is n...

Page 6: ...ogram Pause Facility While firing press and hold down the ª key for about 4 seconds The ST312A will pause the executing program To un pause the program press and hold down the ª key again for about 4 seconds The effects of pausing are as follows If paused during a ramp the kiln temperature will be held soaked indefi nitely at the current kiln temperature The ramp will continue when un pause is sel...

Page 7: ...re If currently soaking then the ST312A will end the firing Changes made to the operation of the ST312A in this way are temporary and are not stored Adjusting While Firing ST312A User Handbook Page 7 When the ST312A is not firing there are no lamps lit on the mimic panel the run lamp is off and the display shows the kiln temperature with the C indicator lit Altering the program 20 C C hr hr min If...

Page 8: ...se through the programming steps to correct errors or to exit programming mode Note available ramp rate displays are End 1 999 FULL If End is shown but another segment is required then push the key to obtain the required ramp rate in the range 1 C hr to 999 C hr If full power is required then push the key until FULL is diplayed ST312A User Handbook Page 13 Cooling Upon completion of firing the ST3...

Page 9: ...feature can be disabled see installation handbook Firing Delayed Start The delayed start time period is set to 00 00 when the ST312A is turned on ST312A 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 ST31...

Page 10: ...Page ST312A User Handbook 10 Program Record Sheet Ramp 1 C hr t1 C Ramp 2 C hr Soak Temp C Soak Time hr min Please photocopy me ST312A User Handbook Page 11 Program Description Please photocopy me ...

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