ST312A - Stafford Instruments Ltd.
Contents
1. 00 then pressing the START STOP key O Cihr causes firing to commence immediately O hr min 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 ST312A User Handbook Page 9 Please photocopy me Program Record Sheet Ramp 2 Soak Temp Soak Time Program Description C hr C hr min ae Page 10 ST312A User Handbook ST312A User Handbook Page 11 Please photocopy me2. at the current kiln temperature The ramp will continue when un pause is selected If paused during a soak then the soak time will be extended indefinitely The remainder of the soak period will be resumed when un pause is se lected Segment advance key held down for about 4 seconds can also be used to terminate the pause This will advance the segment and will immedi ately terminate a paused soak and end the firing program Changes made to the operation of the ST312A in this way are temporary and are not stored As a warning during pause a double beep is sounded every 10 seconds the display scrolls PAUSEd for 5 seconds then shows the kiln tem perature for 5 seconds c O Chhr O hrmin WARNING PROGRAM PAUSE Adjusting While Firing The program pause facility should be used with care Program execution is suspended and the kiln will be held at its current temperature indefinitely If left too long at high temperatures kiln damage could result ST312A User Handbook Page 15 Adjusting While Firing Firing values can be adjusted while the ST312A is firing Also there are program pause un pause and segment advance features that are particulary useful for glass work Adjusting Firing Values While firing operate the key to select the required parameter as shown by a flashing lamp on the mimic display The firing value is shown on the main display and can now be adjusted with the amp keys in the usual
3. Further copies of this handbook may be found at www staffordinstruments co uk docs st3 12a user3 12a pdf Page 20 ST312A User Handbook TAEFOR ST312A User Handbook STAFFORE ST312A Temperature Programmer ST312A Temperature Programmer Stafford Instruments Ltd www staffordinstruments co uk C Tel 44 0 1785 255588 email support stafford inst co uk Fax 44 0 1785 255589 See separate handbook for User Instructions Issue 2 00 Copyright 2009 Stafford Instruments Ltd Date 01 June 2009 At A Glance DISPLAY MAIN DISPLAY INDICATORS FIRING LAMP CONTROL KEYS 5 SEGMENT MIMIC DISPLAY Q R c 1 Temperature Programmer lt SOAK TEMPERATURE LAMP SOAK TIME LAMP RAMP 2 LAMP tI LAMP DELAYED gt t m START LAMP RAMP 1 LAMP Page 2 ST312A User Handbook Sample Programs Name Ramp 1 t1 Soak temp Soak time Low Biscuit Normal Biscuit High Biscuit Earthenware Low Temperature Glaze Earthenware Mid Temperature Glaze Earthenware High Temperature Glaze Stoneware Glaze On Glaze Enamel Heavy Sculpture Lustre Notes 70 C hr 600 C 960 C 00 15 1000 C 00 15 1160 C 00 15 960 C 00 30 70 C hr 70 C hr 90 C hr 90 C hr 90 C hr Sample Programs Earthenware High Temperature Glaze is also suitable for Stoneware Low Temperature Glaze Stoneware Glaze is also suitable for Porcelain On Glaze Enamel is also suitable for some e
4. P key or turn off the power to the instrument ST312A User Handbook Page 13 iring F Operating Notes Kiln too slow 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 Heating amp Cooling Ramps The ST312A is capable of controlled ramps for both heating and cooling If the soak temperature is set lower than tl 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
5. 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 Memo All programs amp 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 Delayed Start The delayed start time period is set to 02 00 when the ST312A is turned on Page 12 ST312A User Handbook 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 Hint it is good practice to check that the program is correct by pressing e the key amp checking the program contents before pressing the START STOP key to start a firing iring F O C If the left hand decimal point is on then O cihr the keyboard is locked amp the ST312A will not respond to the START STOP O hr min key Press the amp keys together amp hold down for 5 seconds to unlock O C If a delayed start has been set then press ing the START STOP key causes a time O Cihr delay to start The time remaining is hr min 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 c If no delayed start has been set 00
6. ds to unlock The controller settings can be reviewed by pressing the key Note holding down the tor keys causes rapid change of the displayed value O c O Chr hr min O c Chr O hr min c O Chr O hr min O c chr O hr min c O Chr O hr min ST312A User Handbook The first push of the key displays the start delay time in the range 00 00 to 99 59 99 hours 59 mins This can be altered with the amp keys The DELAYED START lamp on the mimic display will flash then displays ramp rate 1 in the range 1 to 999 C hr or FULL or End This can be altered with the t amp keys RAMP 1 lamp on the mimic display will flash then displays temperature t1 in the range 0 to 1320 C This can be altered with the amp keys The tl lamp on the mimic display will flash then displays ramp rate 2 in the range 1 to 999 C hr or FULL or End This can be altered with the t amp keys The RAMP 2 lamp on the mimic display will flash then displays the soak temperature in the range 0 to 1320 C This can be altered with the amp keys The SOAK TEMPERATURE lamp on the mimic display will flash Page 7 Programming Programming O c The next push of the key displays the O chr soak time in the range 00 00 to 99 59 99 hours 59 mins This can be altered with hrmin the amp keys The SOAK TIME lamp on the mimic display will flash A further push
7. e R S K or N type HA C rror 3 Thermocouple reversed kiln Q O Chr temperature apparently less than 40 C R type S type This is an installation fault Get wiring YP yP thermo thermo O hrmin checked couple couple O c Error 4 Kiln temperature too high The 5 kiln has been on zero power for 30 o ap O on minutes but the kiln temperature has not Ha oe al bel ea O hr min fallen by at least 1 C couple couple Possible causes are contactor failure or thermocouple connection intermittent or high resistance c The final display should show the O c Error 5 Kiln temperature overshoot The O Clhr kiln temperature exceeds the desired temperature by at least 10 C 20 C O hr min installer selectable O Chr kiln temperature 20 C shown here with the C indicator on All O hr min other lamps should be off c If the left hand decimal point is on then the keyboard is locked This is O C hr an anti tamper feature Press the Obrmin amp keys together amp hold down for 5 seconds to unlock O c Error 6 Maximum firing time exceeded O cihr The length of the current firing has exceeded an installer selectable 10 999 O hrmin hours limit If any mimic panel lamps are on then O C the ST312A is firing Press the O Chr START STOP key to stop the firing O himin During firing the right hand decimal point will light to show when the kiln is heating Page 16 ST312A User Ha
8. ecets 4 Turning Osaisko apeere Programming re ccanceuseostccendeneesede enseereaenatncdsicunten 6 FDO eee A E 9 COONS eo a RE 13 Adjusting While Firin s csssscssesscsnievesncans 14 Error Messages seeeseeeeeeesseeeresssereessssee 16 Other Features ox saesgsvevcvistapteniaveencsiaaceesan es 18 Sample PROSTARNIG sicsspiscarsnsnnvdawncsoenceenncdaonee 19 Features e Single program e 2 controlled heating cooling ramps soak e Soak time up to 99 hours 59 mins e Ramp rates from 1 to 999 C hour full e Suitable for ceramics and glass use e Program can be altered while firing e Program pause un pause segment advance facilities e Keyboard lockable e Delayed start facility up to 99 hours 59 mins e Power failure recovery e Energy used display e Alarm buzzer amp alarm output Page 4 ST312A User Handbook O C Error 7 Maximum room temperature O Chr exceeded The internal temperature of the ST312A has exceeded an installer O hr min selectable 30 70 C limit Possible causes are room vent fan failure ventilation grills blocked kiln room too small damper or bung left open These error messages cause the ST312A 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 Note these error mes
9. namelling work Heavy Sculpture is also suitable for Terracotta ST312A User Handbook Page 19 Other Features Other Features Energy Used Display Pressing the button at any time shows the amount of electrical energy used in kW hours If pressed during a firing it shows the energy used so far After a firing it shows the total energy used for that firing This information is stored while power is off and is only reset to zero when a new firing is started If the value displayed is always 0 0 then the kiln power rating has not been configured into the ST312A see installation handbook Keyboard Lock Facility The keys on the ST312A can be locked so that pressing them has no effect This is an anti tamper feature used to ensure that the operation of the ST312A or the program data cannot be altered by un authorised people The ST312A can be locked when it is idle not firing or while it is firing It cannot be locked while it is being programmed c If the left hand decimal point in the dis O Chr play is lit then the ST312A is locked Press and hold in both the amp keys O hr min for 5 seconds to unlock the ST312A O C If the left hand decimal point in the display O Chr is not lit then the ST312A is not locked Press and hold in both the amp keys for O hr min 5 seconds to lock the ST312A Power Failure Recovery If power fails during firing then the ST312A recovers as follows For power failure during
10. ndbook ST312A User Handbook Page 5 On Turning Programming Programming The firing segment soak period soak temperature The ST312A firing segment comprises 2 ramps followed by a soak period This single segment can be used for simple firing biscuit firing for exam ple The ST312A ramps the kiln temperature at ramp rate until the kiln reaches temperature t1 It then ramps the kiln temperature to the soak temperature at ramp rate 2 It then soaks dwells at the soak temperature for the soak time It then allows the kiln to cool naturally The ST312A is capable of both positive heating ramps and negative cooling ramps as used in glassmaking for annealing Ramp rate amp ramp rate 2 are settable in the range 1 C hour to 999 C hour or FULL full power or End end of program tl amp the soak temperature are settable over the range 0 to 1320 C The soak time is settable over the range 00 00 no soak to 99 hours 59 mins Note during soaking the ST312A display alternates every 5 seconds between kiln temperature and soak time remaining Page 6 ST312A User Handbook Program Pause Facility While firing press and hold down the key for about 4 seconds The ST312A will pause the executing program To un pause the program press and hold down the 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
11. of the key completes data entry and no lamps on the mimic display will flash Orc Data entry is also completed if End is selected with the key for either ramp rate 1 or ramp Chhr rate 2 O hr min Note available ramp rate displays are End 999 amp 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 Note to exit programming without cycling through all of the above steps wait 10 seconds without pressing any keys the ST312A will revert to the idle display Alternatively press the START STOP key to exit programming and to begin firing immediately Note the key can be used to reverse through the programming steps to correct errors or to exit programming mode Page 8 ST312A User Handbook Cooling Upon completion of firing the ST312A lights all lamps on the mimic display and the kiln is allowed to cool naturally c O Chr O Chhr O hr min O hr min While the kiln temperature is above 40 C the display alternates every 5 seconds between the kiln temperature and Hot O c c O Chhr O Clhr O hr min O hr min When the kiln has cooled to less than 40 C the display alternates every 5 seconds between the kiln temperature and End O c Cooling To return the ST312A back to idle condition ready for the next firing press the START STO
12. sages are provided to detect kiln faults and so offer some protection to the kiln For increased protection the use of a heat fuse or other independent over temperature trip is recommended such as the Stafford Instruments ST121 Technical note any error message will cause the auxiliary alarm relay if fitted to open see installation handbook for details ST312A User Handbook Page 17 Error Messages Turning On Oc Error 1 The kiln temperature is not O chr increasing as required The kiln has been on full power for 1 hour but the kiln O hr min temperature has not risen by at least 8 C When turned on the ST312A performs a display test by briefly illuminating all of the display digits and all of the front panel lamps Possible causes are kiln door or lid not closed properly heater element failure elements too old power phase failure contactor failure or thermocouple short circuit The version number of the software embedded within the ST312A is now displayed If you ever need technical support you will be asked for this HA O C Error 2 Thermocouple or thermocouple code together with the ST312A s serial number laD O Chr wiring open circuit Get thermocouple ON O bmi and wiring checked Have thermocouple Next displayed is the thermocouple type to which the ST312A is set This eS rmn replaced if necessary thermocouple type setting should match the type of thermocouple fitted to A O Ea ak i d amp il the kiln and can b
13. 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 the ST312A ramps back up to soak temperature at ramp rate 2 then applies the remaining soak period This recovery scheme can be disabled if required see installation handbook the ST312A will then lock up with FAI L displayed and kiln off in the event of power failure Page 18 ST312A User Handbook Quick Start Guide Switch on amp wait for kiln temperature display To run a firing program set up previously press the START STOP key To stop the firing at any time press the START STOP key again To review firing data press the key to enter the programming menu To change firing data press the t amp keys to change the displayed value Use the key again as necessary to index to the next firing value to be reviewed or changed To exit the programming menu either wait 10 sec onds or press the START STOP key to start firing If the keyboard is locked then press the amp keys together amp hold down for 5 seconds to unlock ST312A User Handbook Page 3 Quick Start Guide Contents Features Contents ALA GlaNC Eseia neiise ania 2 Quick Start Guide ee ccoticss wiecutdecsnssiarerexeocnaseveds 3 OGG i cicea ose staeapndioGiaeeast renee 4 Features ca ccasssinscclvantdccenststecewascadieasianiucnid
14. way Firing will still carry on as normal while these changes are being made The ST312A will return to its normal running display 10 seconds after key presses cease or immediately after End is displayed Changes made to the program in this way are stored and are used for subsequent firings Segment Advance Facility While firing press and hold down the key for about 4 seconds The ST312A will sound a short beep and the executing program will immedi ately advance one step as indicated by lamps on the mimic panel The effect of this is as follows Ifa start delay is currently executing then the ST312A will terminate this and start firing immediately Iframp 1 segment is currently executing then the ST312A will switch to ramp 2 using ramp rate 2 from the current kiln temperature Adjusting While Firing If ramp 2 segment is currently executing then the ST312A will switch to soak at the current kiln temperature 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 Page 14 ST312A User Handbook Altering the program 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 c O Cihr O hr min If the left hand decimal point is on then the keyboard is locked Press the amp keys together amp hold down for 5 secon
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