Stafford Instruments ST215C User manual

ST215C User Handbook Page 1
Temperature Programmer Handbook
Issue: 6.053
Date: 25 May 2021
© Copyright 2020 - 2021 Stafford Instruments Ltd.
www.staffordinstruments.co.uk
TAFFOR
S
D
ST215C

Page ST215C User Handbook
2
At a Glance
temperature icon
ramp rate icon
time icon
radio icon
mimic display
segment display
main display
start/stop key
running LED
up key
right key
down key
left key
event LED
event key
fuse
cable
on/off switch
USB ready LED
USB socket
Segment

ST215C User Handbook Page 3
Quick Start Guide
Switch on & wait for kiln temperature display
To run a firing program set up previously press
the ► key
To stop the firing at any time press the ► key
again
To review firing data press the ► key to enter
the programming mode
To change firing data press the ▲ & ▼ keys to
change the displayed value
Use the ► key again as necessary to step to
the next firing value or segment to be reviewed
or changed
To mark the end of a program set a ramp rate to
End with the ▼ key
To exit the programming mode either wait 20
seconds or press the ► key to start firing
If the keyboard is locked then press the ▲ & ▼
keys together & hold down for 5 seconds to un-
lock

Page ST215C User Handbook
4
Contents
At a Glance .................................................2
Quick Start Guide........................................3
Contents......................................................4
Features ......................................................5
Turning On ..................................................6
Programming...............................................7
Control Relay Option...................................9
Firing .........................................................12
Cooling ......................................................13
Operating Notes ........................................14
Adjusting While Firing ...............................15
Error Messages.........................................16
Sample Glass Programs ...........................18
Sample Ceramics Programs .....................19
Other Features ..........................................20
WiFi & USB Datalogging Option ...............21
Installation .................................................26
Characteristics ..........................................32

ST215C User Handbook Page 5
32 programs each with 32 segments
1 controlled heating / cooling ramp + soak per segment
Soak periods up to 99 hours 59 mins
Ramp rates from 1 to 999°/hour + FULL
Ideal for glass or ceramics use
Programs can be altered while firing
Program pause and advance facilities
Keyboard lockable
Delayed start facility - up to 99 hours 59 mins
Power failure recovery
Energy used display
Setpoint display
Alarm buzzer & alarm output
Event/damper/fan control relay option
WiFi + USB datalogger option
°C/°F operation
Features

Page ST215C User Handbook
6
Turning On
The version number of the software embedded with-
in the ST215C is now displayed. If you need tech-
nical support you might be asked for this code to-
gether with the serial number.
Next displayed is the thermocouple type
setting. This should match the type of ther-
mocouple fitted to the kiln and can be R, S, K
or N type (r,S,H,n).
The final display will show the kiln tempera-
ture. All other lamps should be off.
If pressing any key causes LOC to appear then
the keyboard has been locked. This is an anti-
tamper feature. Press the ▲ & ▼ keys together
& hold down for 5 seconds to unlock.
During firing the right-hand decimal point will
light to show when heating power is being
applied to the kiln.
This now shows that the keyboard is UN-
LOCKED. To re-lock the keyboard press the ▲
& ▼ keys together & hold down for 5 seconds.
If any mimic panel lamps are on then the ST215C is firing. To stop the firing press the
► key.
Note: During power up the SEGMENT display shows the
operating units (°C/°F) of the ST215C (Installer adjustable).
When turned on the ST215C performs a dis-
play test by lighting all of the display seg-
ments and illuminating all of the front panel
indicator lamps.

ST215C User Handbook Page 7
Programming
A firing segment
An ST215C firing segment comprises a ramp followed by a soak period. Two segments
can be used for simple firing (biscuit firing for example) or several segments can be used
per program for complex firing (crystal glazing or glass-making for example).
The ST215C ramps the kiln temperature at the required ramp rate until the kiln reaches
the soak / target temperature. It then soaks (dwells) at the soak temperature for the soak
period. It then runs the next segment until the end of the program is reached.
The ST215C is capable of both positive (heating) ramps and negative (cooling) ramps -
as used in glassmaking for annealing. The type of ramp is clearly shown on the mimic
display during firing.
The ramp rate is settable in the range 1°/hour to 999°/hour or FULL (full power) or End
(end of program).
The soak / target temperature is settable over the range 0 to 1400°C (2552°F).
The soak period is settable over the range 00.00 (no soak) to 99 hours 59 mins.
Note: during soaking the ST215C display alternates every 15 seconds between
kiln temperature and soak period remaining.
Cooling Ramp
Heating Ramp
Soak Period
Soak Temperature
(target temperature)

Page ST215C User Handbook
8
When not firing there are no indicators lit on
the mimic panel, the run indicator is off and
the display shows the current kiln
temperature.
Altering a program
The controller settings can be reviewed by pressing the ► key.
The first push of the ► key flashes the program
number display. The required firing program
can now be selected with the ▲ & ▼ keys.
Note: holding down the ▲ or ▼ keys causes rapid change of the displayed value.
The next push of the ► key displays the ramp
rate in the range End, 1-999°/HR or FULL.
This can be altered with the ▲ & ▼ keys. The
heating ramp or the cooling ramp indicator on
the mimic panel will flash. End marks the end
of the program. FULL heats or cools as fast
as possible.
The next push of the ► key displays the soak
temperature. This can be altered with the ▲
& ▼ keys. The soak temperature indicator
on the mimic panel will flash.
The next push of the ► key displays the soak
period in hours:minutes. This can be altered
in the range 00:00 to 99:59 with the ▲ & ▼
keys. The soak period indicator on the mimic
panel will flash.
The next push of the ► key increments the segment number digit and
firing data for the next segment can be entered.
Program data entry is terminated if End is
selected for a ramp rate with the ▼ key.
Program data entry is also automatically ter-
minated if the maximum number of segments
have been entered.
Note 2: to exit programming without cycling through all of the above steps wait 20 seconds without pressing any
keys - the ST215C will revert to the idle display. Alternatively press the ► key to exit programming and to begin
firing immediately.
Note 3: the ◄ key can be used to reverse through the programming steps to correct errors or to exit programming
mode.
Note 1: 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°/hr to 999°/hr). If maximum heating/cooling is
required then push the ▲ key until FULL is displayed. To mark the end of the program push the▼ key until End is
displayed

ST215C User Handbook Page 9
Control Relay Configuration
While programming either a ramp rate or a soak time the
event output can be switched on or off by pressing the
event key. The event output will be ON when the event
lamp is on. The event output will be OFF when the event
lamp is off. The event lamp also shows the status of the
event output when the controller is running a program.
The ST215C has an optional control relay that can be configured (see installation
section) as: not used, an event output, a damper control output or a fan control output.
Control Relay Option
Event Output
The event output can be programmed to change state at the start of a ramp and also
at the start of a soak period. Thus both ramp and soak events are possible. The
event output is ON (relay contacts are closed) when the event lamp is lit. Prior to
running a program the event output is OFF (relay contact is open). The event output
status is stored within the firing program.
event on event off

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10
To enter the damper temperature configuration menu press the key and the key
down together while the controller is not running a program (firing indicator not lit).
Note: in the sequence below if no key presses are detected within 30 seconds the
ST215C will exit the menu and damper temperature changes will not be saved.
The damper close temperature prompt is
shown. Release the & keys.
Press the key.
The damper close temperature is now shown.
Adjust with the & keys (hold down for
acceleration).
Press the key.
The damper open temperature prompt is now
shown.
Press the key.
The damper open temperature is now shown.
Adjust with the & keys (hold down for
acceleration)
Press the key.
The ST215C will now reset and the new damper control temperatures will be stored.
Note: in the sequence above it is important that the key is pressed a total of 4
times else changes will not be saved.
Damper Output
Damper Operation
Prior to firing the damper will be open. During firing, when the kiln reaches the damp-
er close temperature, the damper will close. The event indicator will be on.
At the end of the firing and when the kiln has cooled naturally to the damper open
temperature, the damper will open. The event indicator will be off.
Note: The event switch has no function for damper operation

ST215C User Handbook Page 11
To enter the fan temperature configuration menu press the key and the key down
together while the controller is not running a program (firing indicator not lit).
Note: in the sequence below if no key presses are detected within 30 seconds the
ST215C will exit the menu and fan temperature changes will not be saved.
The fan start temperature prompt is shown.
Release the & keys.
Press the key.
The fan start temperature is now shown.
Adjust with the & keys (hold down for
acceleration).
Press the key.
The fan stop temperature prompt is now
shown.
Press the key.
The fan stop temperature is now shown.
Adjust with the & keys (hold down for
acceleration)
Press the key.
The ST215C will now reset and the new fan control temperatures will be stored.
Note: in the sequence above it is important that the key is pressed a total of 4
times else changes will not be saved.
Fan Output
Fan Operation
Prior to firing the fan will be off. During firing the fan will start when the kiln tempera-
ture has risen to the fan start temperature.
The fan will remain on until the kiln temperature has risen to the fan stop temperature.
The fan then turns off and remains off.
The event indicator is turned on while the fan is running.
Note: the event switch has no function for fan operation

Page ST215C User Handbook
12
Firing
To start a firing press the ► key. The running (firing) indicator lamp will flash.
Hint: it is good practice to check that the program is correct by pressing the ►
key & checking the program number & program contents before pressing the ►
key to start a firing. It is also a good idea to have a written record of the contents
of the firing programs kept and displayed near the kiln especially if there is more
than one user of the kiln.
With the firing indicator flashing an optional
start delay up to 99 hours: 59 minutes can be
entered with the ▲ & ▼ keys.
Information: The ST215C operates by calculating the amount of energy required by
the kiln every 30 seconds (this period is installer adjustable). If for example 40% of full
energy is required to maintain a particular ramp rate or a particular soak temperature
then the ST215C will apply heating power to the kiln for 12 seconds every 30 seconds.
The kiln heating indicator will light for 12 seconds every 30 seconds. If the kiln has a
contactor then a loud click will be heard both when the kiln heating indicator lights up
and when it goes out. If full heating power is required then the kiln heating indicator
will remain lit. If full cooling is required the kiln heating indicator will remain off.
After 5 seconds, or immediately if the ► key is pressed again, the firing will com-
mence and the firing indicator lamp will remain lit.
To stop the firing prematurely at any time press the ► key again. The firing indicator
lamp will go out.
Note: during ramping the ST215C will perform either controlled heating or controlled
cooling - as indicated on the mimic display. During soaking the ST215C display alter-
nates every 15 seconds between kiln temperature and soak period remaining. At the
end of each segment the segment number display will be incremented.

ST215C User Handbook Page 13
Cooling
Upon completion of firing the ST215C lights all lamps on the mimic display and the kiln
is allowed to cool naturally.
While the kiln temperature is above 40°C the display alternates every 5 seconds be-
tween the kiln temperature and HOt.
When the kiln has cooled to less than 40°C the display alternates every 5 seconds
between the kiln temperature and End.
To return the ST215C back to idle condition ready for the next firing press the ► key
(or turn off the power to the instrument).

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14
If the ST215C is programmed to heat the kiln at a faster rate than the kiln is capable of
then the ST215C 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 ST215C is programmed to cool the kiln at a faster rate than the kiln is
capable of then the ST215C 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 ST215C is capable of controlled ramps for both heating and cooling. The type of
ramp required is determined by comparing the required soak temperature to the soak
temperature in the previous segment and is shown on the mimic display.
► Key Operation
If the ► key is pressed during a firing then the firing will be halted (not paused).
Pressing the ► key again will cause the ST215C to restart the firing from the begin-
ning. The ST215C will look at the current kiln temperature and if this is greater than
the required soak temperature then the ST215C will automatically cool from current
temperature to the soak temperature. This may not be what is desired so the ► 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 next section). This is a better option than using the ► key. The program
advance feature is however available to recover quickly from ► key operation if
required.
Memory
All programs & necessary data are remembered when the ST215C is turned off. In
the event of power failure during firing the ST215C will automatically resume firing
when power is returned (this feature can be disabled: see Installation section).
Delayed Start
By default the delayed start time period is initialised to 00:00 for each firing. The
ST215C can however be configured to remember the delayed start time period (see
Installation section).
Operating Notes

ST215C User Handbook Page 15
Program Pause Facility
WARNING - PROGRAM PAUSE
The program pause facility should be used with care. Program execution is suspended
and the kiln will be held at its current temperature. If left too long at high temperatures
kiln damage could result. Pause will automatically release after an Installer-defined
time period (default: 2 hours - see Installation section).
Adjusting While Firing
Firing values can be adjusted while the ST215C is firing. Also there are program
pause and program advance features that are particularly 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 ▲ & ▼ keys in the usual way. The contents of the current
segment or any segment still to be executed can be changed. Firing will still carry on
as normal while these changes are being made. The ST215C will return to its normal
running display 20 seconds after key presses cease (or immediately after End is
displayed).
Changes made to programs in this way are stored and are used for subsequent firings.
Program Advance Facility
While firing press and hold down the ▲ key for 3 seconds to obtain the (advance)
function. The ST215C 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:-
If ramping then the ST215C will switch to soak at the current kiln temperature.
If soaking then the ST215C will advance to the ramp in the next segment if any, or
else it will end the firing.
Changes made to the operation of the ST215C in this way are temporary and are not
stored.
While firing press and hold down the ▼ key to obtain the װ (pause) function. The
ST215 will sound a short beep and the executing program will pause at the current kiln
temperature. To release the pause repeat the above action.
While paused, the kiln temperature display
will alternate periodically with a scrolling
PAUSEd display and a beep will be sounded.

Page ST215C User Handbook
16
Error Messages
Heating error. The kiln temperature is not
increasing as required. The kiln has been on
full power for 15 minutes but the temperature
has not increased by at least 2°C.
If the ST215C detects a problem the buzzer will sound and an error message will be
displayed. This error message will alternate with a display of kiln temperature. The
segment number display will show where the error occurred.
Possible causes: kiln door or lid not closed properly or door switch faulty or needs
adjusting. Heater element open circuit or elements too old. Electrical power phase
failure or contactor failure.
Thermocouple or thermocouple wiring open
circuit. Get thermocouple and wiring
checked. Replace thermocouple if neces-
sary.
Thermocouple reversed (kiln temperature
apparently less than -40°C). This is an instal-
lation fault. Get wiring checked.
Cooling error. The kiln has been on zero
power for 30 minutes but the kiln temperature
has not fallen by at least 1°C.
Possible causes: contactor failure (contacts welded?) or thermocouple connection
intermittent or high resistance.
Kiln temperature overshoot. The kiln temper-
ature exceeds the desired temperature by a
preset limit as shown below:-
To obtain more information on the error press the ◄ key. The first press will display
the maximum temperature reached in the firing. The second press will display the
length of time that the error has been present. The buzzer will mute.
Desired Temperature Overshoot allowed
Less than 100°C +60°C
More than 100°C but less than 200°C +50°C
More than 200°C but less than 600°C +30°C
More than 600°C +20°C

ST215C User Handbook Page 17
All these error messages cause the ST215C to terminate the firing. The alarm buzzer
will sound once per second. To reset the ST215C turn off the power to the instrument
and have the fault investigated and rectified by your installer or kiln service engineer.
Technical note: these error messages will cause the alarm relay
to open.
Note: these error messages are provided to detect kiln faults
and so offer some protection to the kiln.
Maximum firing time exceeded. The length of
the firing has exceeded an installer selectable
limit.
Maximum room temperature exceeded. The
internal temperature of the ST215 has ex-
ceeded an installer selectable limit.
Possible causes: kiln room vent fan failure, kiln room too small, ventilation grills
blocked, damper or bung left open, controller mounted too close to kiln.
Program Error. This error message is dis-
played if a potential error is detected within the
firing program when the ► key is pressed to
start a firing. The alarm buzzer will sound 3
times and the segment display will show the
suspect segment number. To clear this error press the ► key. The ST215 will now
enter programming mode to allow the suspect program to be viewed and altered if
necessary. If a fault is found then correct it. If no fault is found then press the ► key
again to force the firing program to start. A potential programming error is defined as
a very low ramp rate to a very low temperature. Such a programming fault might
cause very long firing times with potential kiln damage.
Firing Program Errors

Page ST215C User Handbook
18
Sample Glass Programs
Program No.
Program
Description
Seg 1
Ramp
Rate
°C/hr
Seg 1
Soak
Temp
°C
Seg 1
Soak
Time
hr:mn
Seg 2
Ramp
Rate
°C/hr
Seg 2
Soak
Temp
°C
Seg 2
Soak
Time
hr:mn
Seg 3
Ramp
Rate
°C/hr
Seg 3
Soak
Temp
°C
Seg 3
Soak
Time
hr:mn
Seg 4
Ramp
Rate
°C/hr
Seg 4
Soak
Temp
°C
Seg 4
Soak
Time
hr:mn
Seg 5
Ramp
Rate
°C/hr
14-6mm Float Glass Fuse 150 538 00:10 FULL 840 00:20 FULL 538 00:45 182 427 00:15 End 24-6mm Float Glass Slump 150 538 00:00 200 700 00:15 FULL 538 00:15 182 427 00:00 End 36mm Bullseye™ Fuse 222 677 00:30 333 795 00:10 FULL 482 01:00 83 371 00:01 End 46mm Bullseye™ Slump 167 640 00:10 FULL 482 01:00 56 371 00:01 End - - - 56mm Spectrum System 96™ Fuse 200 500 00:00 FULL 804 00:12 FULL 540 00:40 150 510 00:20 End 66mm Spectrum System 96™ Slump 155 704 00:20 FULL 540 01:30 FULL 510 00:10 26 371 00:00 End 7Bottle Firing Cycle 170 510 00:00 250 780 00:10 FULL 510 01:00 70 400 00:30 End 8Low Stain 200 570 00:10 FULL 516 00:30 100 300 00:00 End - - - 9High Stain 200 665 00:10 FULL 550 00:20 FULL 516 00:30 100 300 00:00 End
The ST215C is provided pre-programmed with the glass firing programs below. These programs may be modified or over-written as required.

ST215C User Handbook Page 19
Sample Ceramics Programs
Program
Number
Program Name Seg 1
Ramp
Rate
°C/hr
Seg 1
Soak
Temp
°C
Seg 2
Ramp
Rate
°C/hr
Seg 2
Soak
Temp
°C
Seg 2
Soak
Time
hr.mn
Seg 1
Soak
Time
hr.mn
Seg 3
Ramp
Rate
°C/hr
11 Slow Bisque 60 600 FULL 1000 00.0000.00 End
12 Normal Bisque 100600 FULL 1000 00.0000.00 End
13 High Bisque 100600 FULL 1140 00.0000.00 End
14 Brush-on
Earthenware Glaze
1000°C (Cone 6)
100 300 FULL 1000 00.0000.00 End
15 Standard Earthenware
Glaze 1100°C
100 300 FULL 1100 00.0000.00 End
16 Earthenware High
Temperature Glaze
1140°C
100 300 FULL 1140 00.0000.00 End
17 Mid-Range
Stoneware Glaze
1200°C
100 300 FULL 1200 00.0000.00 End
18 Standard
Stoneware Glaze
1260°C (see note)
100 300 FULL 1235 00.0000.00 End
19 Onglaze 780°C 100400 FULL 780 00.0000.00 End
20 Lustre 750°C 100400 FULL 750 00.0000.00 End
Note
It has been found that a kiln controller will give greater heat work as the temperature
increases. Therefore to achieve a stoneware firing of cone 8-9 we suggest setting the
final soak temperature to 1235°C. A slight adjustment can then be made after the first
firing. It should be remembered that kiln controllers are indicators of temperature and
the effects of faster or slower firings may cause extreme variations in the end result.
This is known within ceramics as “heatwork”. Cones are measures of heatwork and it
is strongly recommended that cones are always used in conjunction with a kiln
controller to appreciate the differences between heatwork and temperature indicated
by the controller. Stoneware firings will also demonstrate the greatest potential
differences between heatwork and indicated temperature.
The ST215C is provided pre-programmed with the ceramics firing programs below.
These programs may be modified or over-written as required.

Page ST215C User Handbook
20
Other Features
Energy Used & Setpoint Displays
Operate the ◄ key at any time to show the amount of electrical energy used in kWh.
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 - see the Installation section of this
handbook.
Operating the ◄ key a second time shows the current set-point (the temperature
which the ST215C is currently trying to achieve).
Keyboard Lock Facility
The keys on the ST215C can be locked so that pressing them has no effect. This is an
anti-tamper feature used to ensure that the operation of the ST215C or the program data
cannot be altered by un-authorised people. The ST215C can be locked when it is idle
(not firing) or while it is firing. It cannot be locked while it is being programmed.
Power Failure Recovery
If power fails during firing then the ST215C recovers as follows:-
For power failure during start delay the ST215C times off the remaining start delay when
power returns. For power failure during ramping the ST215C continues the ramp it was
previously executing. For power failure during soaking the ST215C ramps back up to
soak temperature at the correct ramp rate then applies the remaining soak period. This
recovery scheme can be disabled if required (see installation section) - the ST215C will
then lock up with FAIL displayed and kiln off in the event of power failure.
Press the ▲ & ▼ keys together & hold down
for 5 seconds to lock.
Press the ▲ & ▼ keys together & hold down
for 5 seconds to unlock.