Stafford Instruments ST315B Instruction Manual

ST315B User Handbook Page 1
ST315B
User Handbook
ST315B Temperature Programmer
TAFFOR
S
D
Issue: 3.00
Date: 05 Jan 2021
See separate handbook for Installation Instructions
© Copyright 2009 - 2021 Stafford Instruments Ltd.

Page ST315B User Handbook
2
MAIN DISPLAY
SEGMENT
MIMIC
DISPLAY
DISPLAY
INDICATORS
CONTROL
KEYS
(5)
At A Glance
DELAYED
START LAMP
SOAK TIME LAMP
SOAK TEMPERATURE LAMP
COOLING
RAMP LAMP
At A Glance
FIRING LAMP
Delay
Cooling
Heating
Soaking
HEATING
RAMP LAMP

ST315B User Handbook Page 3
Quick Start Guide
Quick Start Guide
Switch on & 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  &  keys to
change the displayed value
Use the  key again as necessary to index to the
next firing value or segment to be reviewed or
changed
To mark the end of a program set a ramp rate to 
with the  key
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  &  keys
together & hold down for 5 seconds to unlock

Page ST315B User Handbook
4
Contents
Contents
At A Glance.................................................. 2
Quick Start Guide......................................... 3
Contents........................................................ 4
Features ........................................................ 4
Turning On ................................................... 5
Programming................................................ 6
Firing ............................................................ 9
Cooling ....................................................... 13
Adjusting While Firing .............................. 14
Error Messages........................................... 16
Other Features ............................................ 18
Sample Programs........................................ 19
• 9 programs each with up to 9 segments
• 1 controlled heating / cooling ramp + soak per segment
• Soak times up to 99 hours 59 mins
• Ramp rates from 1 to 999°C/hour + full
• Ideal for glass or ceramics use
• Programs can be altered while firing
• Program pause/un-pause + segment advance facilities
• Keyboard lockable
• Delayed start facility - up to 99 hours 59 mins
• Power failure recovery
• Energy used display
• Alarm buzzer & alarm output
Features
Features

ST315B User Handbook Page 5
Turning On
.
. .
..
....
When turned on the ST315B performs a
display test by briefly illuminating all of
the display digits and all of the front pan-
el lamps.
The version number of the software embedded
within the ST315B is now displayed. If you ever
need technical support you will be asked for this
code together with the ST315B’s serial number.
Next displayed is the thermocouple type to which the ST315B is set. This
thermocouple type setting should match the type of thermocouple fitted to
the kiln and can be R, S, K or N type.
‘R’ type
thermo-
couple
‘S’ type
thermo-
couple
‘K’ type
thermo-
couple
‘N’ type
thermo-
couple
°C
°C/hr
hr.min
.
°C
°C/hr
hr.min
.°C
°C/hr
hr.min
The final display should show the
kiln temperature (20°C shown here)
with the ‘°C’ indicator on. All oth-
er lamps should be off.
If the left-hand decimal point is on
then the keyboard is locked. This is
an anti-tamper feature. Press the 
&  keys together & hold down for
5 seconds to unlock.
If any mimic panel lamps are on then
the ST315B is firing. Press the
START/STOP key to stop the firing.
During firing the right-hand decimal
point will light to show when the kiln
is heating.
Turning On

Page ST315B User Handbook
6
Programming
A firing segment
An ST315B firing segment comprises a ramp followed by a soak period.
Two segments can be used for simple firing (biscuit firing for example) or
up to 9 segments can be used per program for complex firing (crystal glaz-
ing or glass-making for example).
The ST315B ramps the kiln temperature at the required ramp rate until the
kiln reaches the soak temperature. It then soaks (dwells) at the soak tem-
perature for the soak time. It then runs the next segment until the end of
the program is reached.
The ST315B 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°C/hour to 999°C/hour or 
(full power) or (end of program).
The soak temperature is settable over the range 0 to 1400°C.
The soak time is settable over the range 00.00 (no soak) to 99 hours 59
mins.
Note: during soaking the ST315B display alternates every 5 seconds
between kiln temperature and soak time remaining.
Programming
soak temperature
heating ramp
cooling ramp
soak period
Delay
ºC
t
Cooling
Heating
Soaking

ST315B User Handbook Page 7
When the ST315B 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 a program
.°C
°C/hr
hr.min
If the left-hand decimal point is on
then the keyboard is locked. Press
the  &  keys together & hold
down for 5 seconds to unlock.
The controller settings can be reviewed by pressing the  key.
The first push of the  key flashes
the program number display. This
can be altered from 1 to 9 with the 
&  keys.
Note: holding down the  or  keys causes rapid change of the displayed value.
.°C
°C/hr
hr.min
The next 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
 &  keys. The DELAYED START lamp
on the mimic display will flash.
°C
°C/hr
hr.min
 then displays the ramp rate in the range 1
to 999°C/hr or  or . This can be
altered with the  &  keys. The
HEATING RAMP or COOLING RAMP
lamp on the mimic display will flash.
°C
°C/hr
hr.min
 then displays the soak temperature in the
range 0 to 1400°C. This can be altered with the
 &  keys. The SOAK TEMPERATURE
lamp on the mimic display will flash.
Programming
PROGRAM

.
°C
°C/hr
hr.min
The next push of the  key displays the
soak time in the range 00.00 to 99.59 (99
hours 59 mins). This can be altered with
the  &  keys. The SOAK TIME lamp
on the mimic display will flash.
A further push of the  key increments the
segment display digit and firing data for the
next segment can be entered.
SEGMENT


Page ST315B User Handbook
8
Note: to exit programming without cycling through all of the above steps wait 10
seconds without pressing any keys - the ST315B will revert to the idle display.
Alternatively press the START/STOP key to exit programming and to begin firing
immediately.
Programming
°C
°C/hr
hr.min
Data entry is terminated if  is selected for a
ramp rate with the  key. Data entry is also
automatically terminated if 9 segments have been
entered.
Note: the  key can be used to reverse through the programming steps to correct
errors or to exit programming mode.
Note: available ramp rate displays are: , …   & . If   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   is diplayed.

ST315B 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.
.°C
°C/hr
hr.min
If the left-hand decimal point is on then
the keyboard is locked & the ST315B
will not respond to the START/STOP
key. Press the  &  keys together &
hold down for 5 seconds to unlock.
.
°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.
.°C
°C/hr
hr.min
If no delayed start has been set (00.00)
then pressing the START/STOP key
causes firing to commence immediate-
ly. Either the Heating or Cooling lamp
on the mimic panel will light. If kiln
heating is required then the right-hand
decimal point on the display will light
while heating power is being applied to
the kiln.
Information: The ST315B operates by calculating the amount of energy
required by the kiln every 30 seconds (installer adjustable). If for example 40%
of full energy is required to maintain a particular ramp rate or a particular soak
temperature then the ST315B 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 number & program contents before
pressing the START/STOP key to start a firing.

Page ST315B User Handbook
10
Program Record Sheet
Segment
No.
Ramp
°C/hr
Soak Temp
°C
Soak Time
hr.min
Please photocopy me!

ST315B User Handbook Page 11
Notes
Please photocopy me!
Program No.

Page ST315B User Handbook
12
Operating Notes
If the ST315B is programmed to heat the kiln at a faster rate than the kiln
is capable of then the ST315B 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 ST315B is programmed to cool the kiln at a faster rate
than the kiln is capable of then the ST315B 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 ST315B 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.
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
ST315B to restart the firing from the beginning. The ST315B will look at
the current kiln temperature and if this is greater than the required soak
temperature then the ST315B will automatically cool from current temper-
ature to the soak temperature. 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 availa-
ble to recover quickly from STOP key operation if required.
Memory
All programs & necessary data are remembered when the ST315B is turned
off. In the event of power failure during firing the ST315B will automati-
cally resume firing when power is returned (this feature can be disabled: see
installation handbook).
Firing
Delayed Start
The delayed start time period is remembered while the ST315B is turned off.

ST315B User Handbook Page 13
Cooling
Upon completion of firing the ST315B lights all lamps on the mimic
display and the kiln is allowed to cool naturally.
 °C
°C/hr
hr.min  °C
°C/hr
hr.min
 °C
°C/hr
hr.min  °C
°C/hr
hr.min
While the kiln temperature is above 40°C the display alternates every 5
seconds between the kiln temperature and 
When the kiln has cooled to less than 40°C the display alternates every 5
seconds between the kiln temperature and 
To return the ST315B back to idle condition ready for the next firing press
the START/STOP key (or turn off the power to the instrument).
Cooling

Page ST315B User Handbook
14
Adjusting While Firing
Firing values can be adjusted while the ST315B is firing. Also there are
program pause/un-pause and segment advance features that are particular-
ly 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 ST315B will return to its normal running display 10 seconds
after key presses cease (or immediately after  is displayed).
Changes made to programs 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
ST315B 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 a start delay is currently executing then the ST315B will terminate this
and start firing immediately.
If ramping is currently executing then the ST315B will switch to soak at
the current kiln temperature.
If currently soaking then the ST315B will advance to the next segment if
any, or else it will end the firing.
Changes made to the operation of the ST315B in this way are temporary
and are not stored.
Adjusting While Firing

ST315B User Handbook Page 15
Program Pause Facility
While firing press and hold down the  key for about 4 seconds. The
ST315B 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 ramping the kiln temperature will be held (soaked) in-
definitely at the current kiln temperature. The ramp will continue when
un-pause is selected.
If paused during soaking 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 - advancing to the next segment (if any).
Changes made to the operation of the ST315B in this way are temporary
and are not stored.

 °C
°C/hr
hr.min
As a warning during pause a double
beep is sounded every 10 seconds,
the display scrolls  for 5
seconds then shows the kiln temper-
ature for 5 seconds.
Adjusting While Firing
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 indefinitely.
If left too long at high temperatures kiln damage could result.

Page ST315B User Handbook
16
Error Messages
Error Messages
Error 1. The kiln temperature is not
increasing as required. The kiln has been
on full power for 1 hour but the kiln
temperature has not risen by at least 8°C.
Error 2. Thermocouple or thermocouple
wiring open circuit. Get thermocouple
and wiring checked. Have thermocouple
replaced if necessary.
Error 3. Thermocouple reversed (kiln
temperature apparently less than -40°C).
This is an installation fault. Get wiring
checked.
Error 4. Kiln temperature too high. The
kiln has been on zero power for 30
minutes but the kiln temperature has not
fallen by at least 1°C
 °C
°C/hr
hr.min
 °C
°C/hr
hr.min
 °C
°C/hr
hr.min
 °C
°C/hr
hr.min
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.
Error 5. Kiln temperature overshoot. The
kiln temperature exceeds the desired
temperature by at least 10°C / 20°C
(installer selectable).
 °C
°C/hr
hr.min
Error 6. Maximum firing time exceeded.
The length of the current firing has
exceeded an installer selectable (10 - 999
hours) limit.
 °C
°C/hr
hr.min
Possible causes are: contactor failure or thermocouple connection intermittent
or high resistance.

ST315B User Handbook Page 17
All error messages cause the ST315B to terminate the firing with all the
keys locked. An alarm buzzer sounds once per second.
SWITCH KILN OFF!
To reset the ST315B 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 messages 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.
Error 7. Maximum room temperature
exceeded. The internal temperature of the
ST315B has exceeded an installer
selectable (30 - 70°C) limit.
 °C
°C/hr
hr.min
Possible causes are: room vent fan failure, ventilation grills blocked, kiln room
too small, damper or bung left open

Page ST315B User Handbook
18
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 start-
ed.
If the value displayed is always . then the kiln power rating has not been
configured into the ST315B - see installation handbook.
Keyboard Lock Facility
.°C
°C/hr
hr.min
The keys on the ST315B can be locked so that pressing them has no effect.
This is an anti-tamper feature used to ensure that the operation of the
ST315B or the program data cannot be altered by un-authorised people.
The ST315B can be locked when it is idle (not firing) or while it is firing. It
cannot be locked while it is being programmed.
If the left-hand decimal point in the dis-
play is lit then the ST315B is locked.
Press and hold in both the  &  keys
for 5 seconds to unlock the ST315B.
°C
°C/hr
hr.min
If the left-hand decimal point in the dis-
play is not lit then the ST315B is not
locked. Press and hold in both the  & 
keys for 5 seconds to lock the ST315B.
Power Failure Recovery
If power fails during firing then the ST315B recovers as follows:-
For power failure during start delay the ST315B times off the remaining start
delay when power returns. For power failure during ramping the ST315B
continues the ramp it was previously executing. For power failure during
soaking the ST315B 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 handbook) - the ST315B will then lock
up with  displayed and kiln off in the event of power failure.
Other Features

ST315B User Handbook Page 19
Sample Programs
Name Ramp 1 t1 Soak timeRamp 2 Soak temp
Low Biscuit 70°C/hr 600°C 00:15FULL 960°C
Normal Biscuit 70°C/hr 600°C 00:15FULL 1000°C
High Biscuit 70°C/hr 600°C 00:15FULL 1160°C
Earthenware Low
Temperature Glaze
90°C/hr 600°C 00:30FULL 960°C
Earthenware Mid
Temperature Glaze
90°C/hr 600°C 00:30FULL 1040°C
Earthenware High
Temperature Glaze
90°C/hr 600°C 00:30FULL 1140°C
Stoneware Glaze 90°C/hr 600°C 00:30FULL 1250°C
On Glaze Enamel 90°C/hr 600°C 00:30FULL 780°C
Heavy Sculpture 50°C/hr 300°C 00:3070°C/hr 1000°C
Lustre 90°C/hr 600°C 00:00FULL 750°C
Sample Programs
Notes
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 enamelling work.
Heavy Sculpture is also suitable for Terracotta.

Page ST315B User Handbook
20
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