STORK TRONIC ST96 Series Quick start guide

ST96-32.09
Deep-frying controller
Order number 900087.004
Wiring diagram
Product description
The micro-processed controller ST96-32.09 serves for temperature control at high measuring ac-
curacy and is foreseen for use with deep fryers. The unit has a 3-digit display and is supplied with
230V AC. The controller has an input for Pt100 temperature sensor and one relay exit. The control
setpoints and parameters determining the process are adjusted with a 5-field plastic foil keyboard.
Sensor: Pt100
Range: -99...850◦C
Front size: 96mm x 96mm
Panel cut-out: 90.5mm x 90.5mm
Connector: plug and socket
1

2

SOFTWARE .09
Features of controller
The controller features a temperature control circuit. The sensor input measures the temperature of
the deep fryer, the relay output controls the heating. The temperature is displayed on a three-digit
display. The LEDs indicate the switching state and control status.
The controller features a control unit with PID characteristic. Four sets of parameters, each with a
P-term, I-term, D-term and a cycle time, can be set up separately, and can be pre-selected or
activated as programs. The upper button quickly changes over to maximum heating power after
the heat-up phase and is referred to as the "turbo button". The controller also features specific
alarm messages on the time the fat operating time indicating that the fat has to be replaced and
finally disabling the controller. For heating types starting after a delay, a switch-off delay is
implemented for the switching output.
Operation
Commissioning the controller
When mains supply is turned on, the controller will always be off, i.e. in standby mode (OFF is
displayed). To turn the controller on/off, press the "ON/OFF" button for approx. 2 seconds. The
delay ensures that the controller is not switched on or off unintentionally.
Heating with cold fat
When the controller is turned on while the fat is cold, slow heating will always be active to ensure
gentle heating of the solid fat. To activate quick heating, press the turbo button. Press the button
again to return to slow heating mode. This button must also be pressed for approx. 2 seconds to
prevent unintentional switching.
Heating with hot fat
When the fat is already hot when mains supply is turned on and the controller is turned on by
pressing the "ON/OFF" button, the control behavior which will be activated depends on the fat
temperature. The clock end defined via parameter "P7" is used as the limit value.
If the temperature is below this limit when the controller is turned on, slow heating will start based
on the clock times defined in parameters "P1" and "P2", after that "Pr.1" will always be activated. If
the temperature is above this limit, "Pr.1" will be active immediately. If "Pr.2...Pr.4" are required
instead, the relevant program must always be activated manually after the slow heating phase.
Activated program after "ON/OFF"
If the controller is switched off, after commissioning, for a short time via the "ON/OFF" button, slow
heating mode will only be active if the temperature is below the limit defined in "P7" if it was
already active before the controller was switched off. However, "Pr.1" will be activated in any case,
i.e. "Pr.1" will always be active without a slow heating phase as well as above the defined limit.
Programs "Pr.2...Pr.4" must always be activated manually after "ON/OFF". Below the limit value,
this is only possible if the limit value was already reached before. Returning from "Pr.1" to slow
heating is possible only if the limit value has not been reached before. Above the limit value,
programs "Pr.1...Pr.4" can be activated as required after "ON/OFF".

Selection/activation of PID programs "Pr.1...Pr.3"
To select or activate the PID programs, button "UP" must be pressed for approx. 2 seconds on
reference value level. The controller will then switch to program selection level, where you can set
a pointer to programs "Pr.1...Pr.3" using buttons "UP" and "DOWN". To select the program on the
display, press "SET" button for approx. 2 seconds. The display will be flashing indicating that the
program was selected successfully.
To return to the reference value level from "PR.1" position, simply press the "DOWN" button for
approx. 2 seconds or perform an Auto Reset, for which a shorter waiting time of approx. 10
seconds is implemented.
If the actual value reaches the limit defined via "P7", the controller will activate the selected
program automatically and maintain it until the actual value drops below the limit again. Above the
limit, programs "Pr.1...Pr.3" are not only selected in the way described above, but also activated
immediately.
Activation of PID program "Pr.4"
Above the limit value defined via "P7" you can use the quick-heating button ("turbo button") to
switch from the pre-selected/activated program "Pr.1...Pr.3" to "Pr.4" and back. Pre-selection of
"Pr.4" is not possible during the first heating phase. If "Pr.4" is active, parameter "A1" determines if
thermostat behavior or PID characteristic based on parameters "P20-P23" is active. Programs
"Pr.1...Pr.3" always have PID characteristic. The appliance is designed such that maximum heating
power is always guaranteed for program "PR.4", irrespective of parameterization.
Automatic return to slow heating
If, with program "Pr.1...Pr.4" activated, the actual temperature drops below the fixed limit of 50 °C,
the controller returns to slow heating mode automatically. In this case, as well as after "Mains
supply On", it is only possible to switch between "Pr.1" and slow heating. This switching option is
given both below and, after brief heating, above 50 °C. Activation of "Pr.2...Pr.4" is deleted, pre-
selection of "Pr.2" or "Pr.3" is maintained.
Function of indicator lamps
The upper lamp "H" indicates the switching state of the output contact. The lamp in the middle
"Slow heating" indicates that the slow heating phase is active. The bottom lamp "Quick heating"
lights up only if program "Pr.4" is active. Lamps "Slow heating" and "Quick heating" are always off
if one to the programs "Pr.1...Pr.3" are active.
Displaying the active program
Press buttons "ON/OFF" and "Turbo" at the same time to display the actually active program for
approx. 4 seconds. Since the individual functions assigned to the two buttons will be activated only
after a delay of approx. 2 seconds, unintentional activation of these functions is not possible if you
press the two buttons simultaneously, as the selected program will be displayed right away. This
display does not affect the control behavior or the controller settings. In slow heating mode, the
display will not respond if you press the buttons.
Hot fat operating hours counter and alarms
In internal counter registers the operating time with hot fat. The counter will be active only if the
actual value is above the temperature set in parameter "P25". Once the time set in parameter
"P26" has elapsed, a fat warning will be triggered. The regular display and the warning "OIL" will
be displayed alternately. In this state, the controller remains operational, parameters can be set,
too. Once the time set in parameter "P27" has elapsed, control will be blocked. Now, all functions
of the controller are disabled and control is deactivated. Only switching to "standby" mode is
possible now. To indicate this state, only the "OIL" message on the display will be flashing.
The fat warning message and control blocking must be activated via parameters "A2" and "A3". If
activated later, it must be noted that the hot fat operating time is registered regardless of the
activation and the alarm functions (warning/blocking) can be triggered immediately or a short time
after activation. The current fat operating time can be checked in parameter "P28". This value

cannot be changed, however. The warning message and control blocking must be acknowledged
by a "Reset". This reset is only possible if the fat which must be replaced has cooled down to a
temperature below 100 °C.
Deleting the internal fat operating time and alarm reset
Press buttons "SET" and "ON/OFF" simultaneously for approx. 10 seconds to reset the internally
registered hot fat operating time to zero. At the same time, this will delete the fat warning message
and enable control again. The fat must be replaced. With the controller turned on, the reset is
possible in all control levels, provided that the actual value is below 100 °C. The display will read
"rES" for approx. 10 seconds. When control is blocked, the controller will return to reference value
level in any case and "Pr.2...Pr.4" will be deactivated; after the reset, slow heating will be active
below the limit value defined in "P7", above this temperature, "Pr.1" will be active.
Switch-off delay for gas heating design
For use with heating types which start after a delay due to their design, a switch-off delay can be
defined for the output relay via parameter "P24". In this case, the switching output will be switched
off after the defined delay. Since this delay is independent of the PID control, the value to be
defined must be considered carefully. Otherwise, there might be uninterrupted heating instead of
the typical heating pulses. The switch-off delay is not active in the slow heating phase.
The control function of the deep fryer controller is explained in the following and will always be
valid while the controller is started.

Control function
Heating phase without manual intervention
Heating phase after activation
(Refer to Figure 1):
After activation and start of the controller, a slow heating phase will always follow when the fat is
cold. This phase is finished when the setpoint is reached, at the latest. In this slow heating phase,
the heating relay clocks, i.e. with the on time set in parameter "P1" being followed by the off time
set in parameter "P2" and vice versa. Slow heating is to ensure that congealed fat is heated up
gently at the start of operation. Via parameter "P7", you can stop the slow heating phase before the
setpoint is reached. If this is not desired, set P7=0.0 K.
Figure 1
Heating phase after slight cooling
(refer to Figure 2):
After minor cooling to temperatures above 50 °C, e.g. loading of small quantities of cold fat, the
normal heating function of the controller is maintained. The new heating phase will not be slowed
down, the heating relay will not be clocked with a thermostat function defined via the
parameterisation and a manually activated program “Pr.4”. If PID function is specified, the heating
relay will only clock within this range. The clock end defined via parameter "P7" does not have any
influence.
Figure 2
Heating phase
after activation
Setpoint
Heating phase
after minor cooling
Setpoint

Heating phase after significant cooling (refer to Figure 3):
After significant cooling to temperatures below 50 °C, e.g. loading of large quantities of cold fat, the
slow heating function is activated again. The heating relay clocks again like in the initial heating
phase, until the setpoint or the clock end below the setpoint defined in parameter "P7" is reached
again. This is to ensure gentle heating of the reloaded fat.
Figure 3
Control after heating
After the heating phase, the controller works with the PID function based on parameter group
"Pr1.". The programs “Pr.2 ... Pr.4” must be activated manually.
Heating phase with manual intervention
Heating phase after activation (refer to Figure 4):
After activation and start, the slow heating phase will start without manual intervention. By pressing
the quick heating button, you can switch over to the normal heating function. Now, the fat will be
heated more quickly. The heating relay will no longer clock based on the times set in parameters
"P1" and "P2" but based on the PID function set within program “Pr.1”. The clock end defined via
parameter "P7" does not have any influence after the manual intervention.
To undo the change-over, press the MELT/TURBO button again. Now, the heating relay will clock
like before the manual change-over again.
The manual change-over function can be used for reducing the heating phase if the fat has melted
visibly and can be heated at a higher rate without any damage. Manual change-over between slow
heating and “Pr.1” is possible only if the controller actually is in the heating phase, i.e. below the
threshold set via parameter "P7". Above this threshold, the turbo button switches from program
“Pr.1” (or 2,3) to “Pr.4” and back again.
Heating phase
after significant cooling
Setpoint

Figure 4
Heating phase after significant cooling (refer to Figure 3, top):
After significant cooling to temperatures below 50 °C, e.g. loading of large quantities of cold fat, a
slow heating phase will start, although the change-over to normal heating mode is effected earlier;
the heating relay clocks like in the initial heating phase.
Thus, manual change-over to normal heating function is only effective for the current heating
phase and will become ineffective as soon as the setpoint is reached, at the latest. After that, as
well as after mains failure and restart, the controller is in normal operation mode with slow heating
phase when the controller is switched on and started or restarted later or in the case of cool-down
to temperatures below 50 °C. The switch-back threshold is can be set via parameter "P79".
First control level:
Setting the main reference values and reference value setback
The main reference value can be viewed by pressing the SET button. Press UP or DOWN key
additionally to change the set value.
Please note that the set value is saved permanently as soon as the buttons are released. The
value will even be maintained in case of power failure. This applies to the reference value and all
control parameters.
Para-
meter
Description of function
Setting range
Standard
setting
Customer
setting
S1
Setpoint 1 P4...P5 60.0 °C
Heating phase after
with manual change-over
Setpoint

Second control level (P parameters):
Setting of control parameters
Press UP and DOWN keys simultaneously for at least 4 seconds to access a control parameter list
(starting with P1).
Use the UP and DOWN key to scroll through the list.
If you press the SET key, the value of the corresponding parameter is displayed. Press UP or
DOWN key additionally to change the value. As soon as you release all keys, the new value is
saved permanently.
If you press the UP and Down button simultaneously or if you don't press a button for more than 60
seconds, the system will return from parameter level to the initial state.
Para-
meter
Description of function
Setting range
Standard
setting
Customer
setting
P1
On time of heating clocking
1...300 sec.
60 sec.
P2
Off time of heating clocking
1...300 sec.
60 sec.
P3
Hysteresis K1 (only if A1=0)
0.1...99.0 K
0.8 K
P4
Lower setpoint limit
60.0...999 °C
60.0 °C
P5
Upper setpoint limit
60.0...999 °C
190 °C
P6
Actual value correction
-10...10.0 K
0.0 K
P7
Clock end below threshold
-99...0.0 K
-30 K
P8
Proportional term ("Pr.1")
0.1...99.0 K
5.0 K
P9
I-term ("Pr.1")
0...15
12
P10
D-term ("Pr.1")
0...15
15
P11
Cycle time ("Pr.1")
8...100 sec.
12 sec.
P12
Proportional term ("Pr.2")
0.1...99.0 K
5.0 K
P13
I-term ("Pr.2")
0...15
12
P14
D-term ("Pr.2")
0...15
10
P15
Cycle time ("Pr.2")
8...100 sec.
12 sec.
P16
Proportional term ("Pr.3")
0.1...99.0 K
5.0 K
P17
I-term ("Pr.3")
0...15
12
P18
D-term ("Pr.3")
0...15
6
P19
Cycle time ("Pr.3")
8...100 sec.
12 sec.
P20
Proportional term ("Pr.4")
0.1...99.0 K
0.1 K
P21
I-term ("Pr.4")
0...15
0
P22
D-term ("Pr.4")
0...15
0
P23
Cycle time ("Pr.4")
8...100 sec.
8 sec.
P24
Switch-off delay for output
relay
0.0...99.0 sec.
6.0 sec.
P25
Temperature limit for fat
operating time registration
60.0...999 °C
160 °C
P26
Fat operating time until
warning message
1..99 hrs.
30 hrs.
P27
Fat operating time until
controller blocked
1..99 hrs.
40 hrs.
P28
Display of fat operating time
(not applicable)
(not
applicable)

Description of parameters:
P1: On time of heating clocking
With this parameter, you can set the on time of the clocked heating phase. Clocking the output
relay is used for gentle heating of solid fat.
P2: Off time of heating clocking
With this parameter, you can set the off time of the clocked heating phase.
P3: Hysteresis K1
The hysteresis is arranged symmetrically at the reference value, i.e. above and below the
switching point, 50 % of the defined total hysteresis are effective.
It must be noted that, in the case of small hysteresis values, the switching frequency will increase
and the service life of the output relays will be reduced accordingly. In critical cases, the controller
can be equipped with semiconductor relays.
The hysteresis will only be effective if "Pr.4" and the thermostat function are activated.
P4/P5: Upper/lower reference value limitation
The reference value setting range can be restricted, i.e. both an upper and a lower limit can be
defined. This ensures that the end user of a system cannot set reference values which are
inappropriate or dangerous for the application.
P6: Actual value correction
A correction can be defined for the actual value. This correction will be effective additively in the
whole measuring range.
P7: Clock end below reference value
With this parameter, you can terminate the clocked heating phase while the temperature is still
below the reference value. If clocked heating is to be active until the reference value is reached,
set P7=0.0 K.
P8: Proportional term ("Pr.1")
Setting of proportional term for PID program "Pr.1". In the proportional term, power supply is
reduced continuously by switching the output periodically until it is zero at the reference value.
P9: I-term ("Pr.1")
Setting of integral factor for PID program "Pr.1". The strength and effect of the I-term is defined.
This setting and the cycle time Tp will result in the integral time Tn. If the factor is set to "0", there
is no I-term.
P10: D-term ("Pr.1")
Setting of differential factor for PID program "Pr.1". The strength and effect of the D-term is
defined. This setting and the cycle time Tp will result in the derivative action time Tv. If the factor is
set to "0", there is no D-term.
P11: Cycle time ("Pr.1")
Setting of cycle time for PID program "Pr.1". The cycle time primarily creates the time reference to
the controlled system and defines the length of a switching period within the proportional term, for
example.
P12-P15: PID parameters ("Pr.2")
Settings according to parameter group "P8-P11" for PID program "Pr.2".
P16-P19: PID parameters ("Pr.3")
Settings according to parameter group "P8-P11" for PID program "Pr.3".

P20-P23: PID parameters ("Pr.4")
Settings according to parameter group "P8-P11" for PID program "Pr.4".
P24: Switch-off delay for output relay
In the case of gas heating, switching off of the output relay is delayed by the set time. With this
setting it can be prevented that the burner is ignited in the case of short switching pulses. It must
be noted carefully that the set switch-off delay is independent of the control and overlaps it.
P25: Temperature limit for fat operating time registration
As soon the temperature is above the value set here, the fat operating time will be registered.
When the operating times set in parameters "P26" and "P27" are exceeded, a warning message
will be displayed or control will be blocked.
P26: Fat operating time until warning message
Here, you can set the time after which a warning will prompt the user to replace the used frying fat.
P27: Fat operating time until controller blocked
Here, you can set the time after which control will be blocked and the user will have to replace the
used frying fat. Once the deep fryer has cooled down, a reset can be performed in order to enable
control again and delete the registered operating time.
P28: Display of fat operating time
Here, you can view the times registered internally when the fat temperature was above the limit set
in parameter "P25". The displayed value cannot be edited, but the value can be deleted by a reset.

Third control level (A parameters):
Setting of control parameters
To access the third control level, enter the second level first and scroll through the parameter list
until you reach the highest parameter. Then, click the UP button for at least 10 seconds. The
message "PA" will be displayed.
Then, press UP and DOWN buttons simultaneously for at least 4 seconds to access the parameter
list of the third control level (starting with A1).
Selection and setting of the A parameters is done in the same way as in the case of the P
parameters. Returning to the initial state is also done in the same way.
Para-
meter
Description of function
Setting range
Standard
setting
Customer
setting
A1
Control characteristic in "Pr.4"
0: Thermostat
1: PID characteristic 1
A2
Activation of fat warning
message
0: not active
1: active
0
A3
Activation of control blocking
0: not active
1: active
0
Description of parameters:
The following values affect the properties of the appliance and
any changes should be considered carefully for this reason:
A1: Control characteristic in turbo program "Pr.4"
Here, you can define the control characteristic to be used while program "Pr.4" is active. You can
choose between thermostat behavior and PID characteristic based on parameter group "P20-P23".
The control philosophy of the controller is such that "Pr.4" has the highest heating power.
A2: Activation of fat warning message
Here, you can define if control is to be blocked when the hot fat time set in parameter "P26" has
elapsed.
A3: Activation of control blocking
Here, you can define if control is to be blocked when the hot fat time set in parameter "P27" has
elapsed.
Important note:
Any modifications by the customer at this control level is not permissible and can result in
dangerous functional changes.
Status messages
Message
Cause
Remedy
F1
Sensor error (sensor F1 broken or short
circuit)
check sensor
EP
Data loss in parameter memory
Repair of controller

Order No.: 900087.004
Technical data of ST96-32.09
Measuring input
F1: Resistance thermometer Pt100-3L
Measuring range: -80...850°C
Measuring accuracy: +/- 0.5K
Outputs
K1: Relay, normally-open contact, 5(1)A 250V
Display
Two 3-digit LED displays, 13 und 10 mm height, colour red
3 LEDs, diameter 3mm, for status display
Power supply
230V 50/60Hz
Connectors
plug and socket
Ambient conditions:
Storage temperature: -20...+70°C
Operating temperature: 0...+55°C
Relative humidity: max. 75% without dew
Enclosure
Front IP50
Installation data
Front size: 96 x 96 mm
Panel cut-out: 90.5 x 90.5 mm
Installation depth: ca. 105 mm with connector
Mounting: by fixing strap