dm00054484

UM1542
User manual
Cold thermostat kit based on AC switches and the STM8S003F3
Introduction
The STEVAL-IHT001V2 thermostat kit (Figure 1) provides a robust and low-cost solution
from STMicroelectronics using a microcontroller and AC switches to control a refrigerator, a
freezer or a fridge/freezer combination. The firmware embeds three different thermostat
control versions: basic (just for compressor and light control), defrost (with defrost resistor
control added) and air circulation (with fan control added). This allows a wide section of the
cold appliances market to be addressed.
The STEVAL-IHT001V2 board controls a single-phase induction motor and a light bulb, and,
optionally, a defrost resistor and a fan, operating on 220/240 V RMS 50/60 Hz mains
voltage. The thermostat kit is operational with 100/120 V RMS 50/60 Hz but a supply
capacitor must be chosen for a 30 mA output DC current (see Appendix H).
The board can operate over an ambient temperature range of 0 to 60 °C. The exact
maximum temperature depends on the power of the loads (Section 3.2).
Figure 1.
STEVAL-IHT001V2 board
For demonstration and application development purposes a graphical user interface (GUI)
has been developed. The PC and STM8 microcontroller, the MCU performing thermostat
regulation, are connected through a USB bus. Since the STM8 MCU is a low-cost MCU not
embedding a USB peripheral, a supplementary STM32 MCU has been added as a bridge
between the PC and STM8 MCU, only in order to allow communication through the GUI.
The GUI is not only used to configure the thermostat (basic, defrost, air circulation), but also
allows control parameters to be set and parameters measured during tests to be obtained
(Section 3.6). This document provides users with all the information needed to get started
with and operate the STEVAL-IHT001V2 thermostat kit. For detailed information on how to
access the MCU in order to modify/measure parameters, please refer to the “Help” menu of
the GUI software.
September 2012
Doc ID 023172 Rev 1
1/43
www.st.com
Contents
UM1542
Contents
1
2
Kit introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1
Package contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2
Board presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1
Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2
Ensured functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3
2.4
3
Temperature control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.2
Compressor control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2.3
Light bulb and buzzer control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2.4
Defrost resistor and fan control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Hardware features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.1
ACS and ACST devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.2
STM8S003 microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3.3
Control side and communication side power supplies . . . . . . . . . . . . . . 12
2.3.4
STM32F103 microcontroller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Graphic user interface (GUI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Using the STEVAL-IHT001V2 thermostat kit . . . . . . . . . . . . . . . . . . . . . 14
3.1
Thermostat versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.2
Loads power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.3
Measure points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.4
Pulse control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.5
Getting started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.6
2/43
2.2.1
3.5.1
Jumper configuration for standalone or PC-driven modes . . . . . . . . . . . 17
3.5.2
Getting started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.5.3
Operating modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.5.4
Instructions for the GUI software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
GUI windows description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.6.1
Temperature control tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.6.2
Timing control tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.6.3
Force debug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.6.4
Parameter measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
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UM1542
Contents
3.6.5
4
Saving data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Appendix A Thermal sensor linearization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Appendix B Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Appendix C Additional pads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Appendix D Bill of materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Appendix E
Procedure to apply IEC 61000-4-4 burst test. . . . . . . . . . . . . . . . . . 36
Appendix F
STM8 program debugging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Appendix G PC interface parameters description . . . . . . . . . . . . . . . . . . . . . . . . 40
Appendix H Capacitor value according to country . . . . . . . . . . . . . . . . . . . . . . . 41
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
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List of figures
UM1542
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
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STEVAL-IHT001V2 board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Board details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Hysteresis law. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Defrost control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Placement of test points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Timing definition for gate current pulses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
GUI - temperature control tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
GUI - timing control window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
GUI - debug mode frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Linear voltage in function of the NTC resistor (for a 5 V power supply) . . . . . . . . . . . . . . . 26
Control side schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Control side schematic - STM8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Interface side schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Additional pads schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Placement of additional pads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Test setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
General graph of a fast transient/burst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
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UM1542
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
ACS vs. TRIAC devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
List of test points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Allowable ranges for gate current pulses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Jumper default configuration in standalone or PC-driven operating mode . . . . . . . . . . . . . 17
Operating mode selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
BOM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Jumper configuration in programming and debugging modes . . . . . . . . . . . . . . . . . . . . . . 38
PC interface parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
C29 capacitor value according to the country. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
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Kit introduction
UM1542
1
Kit introduction
1.1
Package contents
The following items are supplied in this package:
1.2
●
A thermostat board (ref.: STEVAL-IHT001V2)
●
An M2020 5k NTC from EPCOS (ref.: M2020/5k/A20)
●
A CD-ROM, including product presentations and datasheets, user manual (this
document), application notes, firmware and the GUI software.
Board presentation
The STEVAL-IHT001V2 thermostat kit board is ideally separated in two parts as shown in
Figure 2. All devices dedicated to thermostat control are placed on the left side (control
side). All devices dedicated to communication with the PC are placed on the right side
(interface side).
Figure 2.
Board details
Control side
Interface side
On/off LED
Temp setting
push buttons
Jumpers for working
mode setting
Optoinsulators
Capacitive
power supply
Temp setting
LEDs
Load connectors
Compressor
Light bulb
Defrost
Fan
ACS
NTC Door switch
conn. conn.
Switch for shared pins
PC GUI vs stand alone
STM32
STM8
AM12238v1
6/43
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UM1542
Kit introduction
These two parts consist of (see Appendix B for the schematic):
●
●
Control side:
–
Capacitive power supply, supplying only the control side of the board. The average
output current of the capacitor power supply is about 25 mA with the embedded
1 µF C29 capacitor (for a 230 V-50 Hz line RMS voltage)
–
STM8S003 microcontroller, low-cost MCU dedicated to thermostat control
–
AC switches: an ACST610-8FP, an ACS110-7SN and two ACS102-6TA, which
control a compressor, a defrost resistor, a light bulb and a fan, respectively
–
One red ON/OFF LED. This LED turns ON when the board is powered
–
Five green LEDs for temperature set point visualization
–
Two push buttons to increase/decrease the temperature set point: Temp+ and
Temp-
–
A buzzer to warn the user if the appliance door has been open for long time
–
Connectors for the NTC and door switch
–
One switch to simulate the door switch
Interface side:
–
STM32F103 microcontroller to implement USB interface
–
Opto-insulators to implement safety insulation between the board and the
computer to allow communication with the GUI when the board is plugged into the
line voltage
–
DC/DC converter to supply the opto-couplers from the USB supply
–
Switches for standalone/PC-driven configuration (see Section 3.5.1)
–
Mini-USB connector
The control side is independent from the interface side, i.e. control is ensured by powering
on the control side only (in this case no GUI interfacing is allowed, of course).
Warning:
Safety insulation is implemented between the board and the
computer to allow GUI communication when the board is
plugged into the line voltage, but the control side of the board
is not electrically isolated from the AC input. The STM8
microcontroller is directly linked to the mains voltage. There
is no insulation between the accessible parts and the high
voltage. The STEVAL-IHT001V2 kit must be used with care
and only by persons qualified for working with electricity at
mains voltage levels. Any measurement equipment must be
isolated from the mains before powering the board. To use an
oscilloscope with the kit, it is safer to isolate it from the AC
line. This prevents a shock from occurring as a result of
touching any single point in the circuit, but does not prevent
shocks when touching two or more points in the circuit.
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Functional description
UM1542
2
Functional description
2.1
Performance
This board has been developed to fulfill the following requirements:
●
Suitability for a wide range of cold appliances: this thermostat board can control the
loads traditionally used in low, medium and high-end cold appliances - compressor,
light, defrost resistor (if present), fan (if present).
●
All AC loads are switched on at mains zero voltage, and operate in full-cycle conduction
mode. This allows suppressing any EMI conduction noise.
●
Electromagnetic compatibility: the board is able to withstand bursts up to 3.1 kV during
IEC61000-4-4 standard tests without any operational problem. Surge tests have also
been performed (IEC61000-4-5 standard) with bursts of 2 kV applied without any
damage to the semiconductors.
●
Compliance to safety standards: a 2 mm gap is ensured between all high-voltage and
low-voltage parts (to obtain a functional level of isolation). The thermal sensor (NTC) is
a class-2 sensor and can be put on non-earthed accessible and conductive parts.
The STEVAL-IHT001V2 kit provides added value in terms of:
●
●
●
Low-cost solution for spark-free thermostat
–
No need for a sealed version
–
Low-cost STM8S microcontroller for thermostat control
–
Low-cost capacitive power supply
Efficiency
–
Fridge consumption lowered by adjusting and reducing the hysteresis threshold of
the temperature control (not easy with mechanical thermostats)
–
Improved efficiency by turning on the defrost resistor only when it's useful and not
at each OFF cycle of the compressor (as done in some mechanical thermostats)
Flexibility
–
Customization: program setting with PC interface to change firmware variables
–
Industrialization: end-of-production MCU programming thanks to FLASH, for soft
upgrade and efficient MCU stock management
2.2
Ensured functions
2.2.1
Temperature control
For the thermal sensor, an insulated class-2 NTC resistor has been used. The part number
is B57020M2502A020 from EPCOS which is commonly used for these applications. The
value of this resistor increases when temperature decreases according to an exponential
law. In order to linearize this relation, thus allowing an easier measurement, a series resistor
has been added (see Appendix A for details).
The NTC must be placed on the evaporator of the fridge or the freezer. The controlled
evaporator temperature should be in the range: [-40 to 10] °C.
Temperature regulation is achieved by hysteresis control (see Figure 3).
8/43
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Functional description
Figure 3.
Hysteresis law
#OMPRESSORSTATUS
/.
(YSTERESIS
/&&
4,/7?LIM
4()'(?LIM
%VAPORATOR
TEMPERATURE/2$%2
%VAPORATOR
TEMPERATURE
!-V
Five temperature set points have been implemented:
1.
Very low
2.
Low
3.
Medium
4.
High
5.
Very high
For each temperature set point an evaporator temperature, a hysteresis, thus an upper limit
and a lower limit are defined. THIGH_lim and TLOW_lim are respectively the upper and the
lower limits of the hysteresis and are defined as:
Equation 1
THIGH _ lim = EvaporatorTemperature +
Hysteresis
2
TLOW _ lim = EvaporatorTemperature −
Hysteresis
2
Equation 2
The compressor is switched on if the sensed temperature is above THIGH_lim, and switched
off when this temperature becomes lower than TLOW_lim. When the door is open
(Section 2.2.3), temperature control is not allowed, i.e. any action on TEMP+ and TEMPhas no effect. The temperature set point, or temperature order, can be set at one of the five
levels by means of the two push buttons PB1 and PB2 (temperature setting push buttons) in
standalone mode (see Figure 2) or by means of the GUI in PC-driven mode (Section 3.6),
while the hysteresis value can only be changed using the GUI.
Five LEDs - D4, D5, D6, D8, D9 (temperature setting LEDs) (Figure 2) in standalone mode,
or VL, L, M, H, VH in PC GUI driven mode (Figure 7) - turn on according to the temperature
set point.
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Functional description
2.2.2
UM1542
Compressor control
The ACST610-8FP device (referred to as Q1 in Appendix B) is used to turn on and off the
compressor according to the evaporator temperature, sensed through the NTC resistor.
Enough room around this AC switch has been left available to add a heatsink if needed.
2.2.3
Light bulb and buzzer control
The slider SW2 on the thermostat board has been placed on the board in order to simulate
the fridge/freezer door. A light bulb is switched on or off according to the position of the door
switch, open or closed respectively. The embedded switch may be replaced by an external
switch using connector J15, in which case switch SW2 must be set in the “Open” position.
If the fridge door or the door switch remains in the open position more than one minute, the
buzzer PZ1 sounds and the LEDs D4, D5, D7, D8, D9 flashes. The buzzer can be stopped
by pressing the Temp+ or Temp- button once (the LEDs keeps on flashing while the door is
in the open position). In the PC GUI driven mode the buzzer can be stopped with the GUI
software (refer to the “Help” menu of the GUI). When the door is open, the temperature
order can only be changed using the GUI software.
The light bulb is driven by the ACS102-6TA, Q4 on the thermostat board (Appendix B).
It should be noted that an R23 resistor has been added in series with Q4. Indeed, as the
lamp lifetime ends, the filament breaks. The overall filament can be short-circuited by the
flashover, and the load current is no longer limited. This current can exceed the i²t capability
of the ACS and destroy it (cf. AN1172). To avoid destroying the ACS102 at each lamp
flashover, a power resistor is added in series with the light. This resistor is rated in order to
limit the ACS current to its ITSM value (10 A for a 10 ms half sinus conduction). In this case,
a 33 Ω 1/2 W resistor is sufficient.
These resistor pads could be also used to put an inductor to limit the dI/dt if a CFL/LED lamp
is used in dimming mode.
2.2.4
Defrost resistor and fan control
Defrost resistor is controlled only when the thermostat is set to “Defrost” or to “air
circulation” versions; while the fan is controlled only in the “air circulation” version.
The defrost resistor is driven by the ACS110-7SB2, Q2 on the thermostat board (see
Appendix B).
This device is turned on following the “Defrost activation delay” parameter time defined in
the GUI software. This time is compared to the sum of the compressor ACST ON times.
When this sum is higher than the “Defrost activation delay”, defrost resistor ACST is enabled
and then switched on as soon as the evaporator temperature is higher than THIGH_lim
(Figure 4). It remains on during the “Defrost duration” time defined in the GUI software.
The conduction starts just before the conduction cycle of the compressor in order to reduce
power consumption.
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Functional description
Figure 4.
Defrost control
Evaporator temperature evoluon
THIGH_lim
TLOW_lim
t
Compressor
t
Δt
DEFROST
t
Sum of Compressor ON mes > DEFROST ACTIVATION DELAY
DEFROST ENABLED
Aer DEFROST DURATION (Δt)
DEFROST TURN-OFF
Compressor turn-on
Evaporator temperature > THIGH_lim
DEFROST TURN-ON
AM12240v1
Fan control is only available in the “air circulation” fridge version. The fan is driven by the
ACS102-6T, Q3 on the thermostat board (Appendix B).
The fan is on at the same time the compressor is on, except if the door is open (in that case
the fan is turned off while the compressor is still running).
2.3
Hardware features
2.3.1
ACS and ACST devices
The STEVAL-IHT001V2 board embeds an ACST610-8FP, an ACS110-7SN, and two
ACS102-6T. Table 1 summarizes the main differences between ACS and ACST and
traditional TRIACs.
Table 1.
ACS vs. TRIAC devices
Device
Z0107
ACS102
Z0109
ACS110
BTA06-SW
ACST610
Igt (mA)
5
5
10
10
10
10
Overvoltage
protection
No
Yes
No
Yes
No
Yes
(dV/dt)
20 V/µs
300 V/µs
50 V/µs
500 V/µs
40 V/µs
500 V/µs
(dI/dt) at turn-on
20 A/µs
50 A/µs
20 A/µs
50 A/µs
50 A/µs
100 A/µs
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Functional description
2.3.2
UM1542
STM8S003 microcontroller
The MCU used in the thermostat kit is the STM8S003F3P6 belonging to the STM8S003
MCU family. It embeds a large number of features at minimum cost. This part number is
used in order to minimize the number of pins. This causes some pins to be shared for
different function recovery (LED3/SWIM_line, LED4/USART_CTS and LED5/USART_TX,
Figure 12). The functions shared are functions dedicated to communication, i.e. no pin
sharing in standalone mode. In order to further reduce costs, the internal oscillator has been
used in order to generate the clock.
2.3.3
Control side and communication side power supplies
A capacitive power supply is used for the control side of the board. A 1 µF capacitor, C29,
has been chosen to supply the board - i.e. the control side of the board - with 25 mA, which
is the maximum average current sunk by the control board (230 V-50 Hz line RMS voltage).
For more information about the design of the capacitive power supply, please refer to the
application note AN1476.
In order to reduce the surge current, an R25 resistor is used in series with the C29
capacitor. Even if the power dissipation of this resistor is limited to ½ W for a 30 mA output
DC average current (for R25 = 47 Ω and 230 V line RMS voltage), a 2 W resistor has to be
used on the board to sustain the inrush current.
One particularity of STEVAL-ITH001V2 board power supply is that it is “negative”. Indeed,
the Vdd terminal is connected to neutral which means that the GND voltage is 5 V below
neutral. This type of connection is mandatory to drive ACS devices. Indeed, ACSs can only
be triggered by a negative current (i.e. sourced from the gate).
The communication side (with the STM32F103 microcontroller), is only supplied by the PC,
by means of the USB connector, through the voltage regulator U2 (see Appendix B).
2.3.4
STM32F103 microcontroller
As for the connection between the PC and the STM8 microcontroller, a USB bus is used.
Since the low-cost MCU dedicated to thermostat control does not embed a USB interface, a
second MCU has been used to work as a gateway between the PC and the STM8. This
MCU is an STM32F103C6, belonging to the STM32F103 family.
It is only used for demonstrative purposes, i.e. for communication in PC GUI driven mode.
2.4
Graphic user interface (GUI)
The graphical user interface (GUI) was developed in order to allow the user to set some
control parameters, to configure the thermostat for the different versions (basic, defrost, air
circulation), and to acquire variables during tests. The user can also choose to program the
STM8 microcontroller with new control parameters.
The connection with the PC, using the USB interface, is ensured by the STM32 MCU
embedding a USB peripheral.
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Functional description
The GUI provides the following features (refer to the “Help” menu of the GUI software for
more information):
●
Slide bars to change the MCU parameters (refer to Figure 7 and 8):
–
Temperature hysteresis
–
Evaporator temperature set point for each thermostat order
–
Gate current pulse widths and delays
–
Time before defrost activation and defrost duration
–
ZVS delay (synchronization of MCU commands with the mains voltage)
●
Virtual knob to set the evaporator temperature level
●
Virtual switch (“debug active”) to force the loads to on or off states (compressor, light,
defrost, fan) for easier board validation
●
Measurement and storage of several parameters during operation (duty cycle and
running period of the compressor, evaporator temperature evolution, mains frequency
and load status).
The most recently modified variables with the GUI can be stored for operation in standby
mode.
It can be noted from Figure 2 that the part of the PCB dedicated to the PC interface is
clearly separated from that part of PCB dedicated to thermostat control in order to easily
visualize the component count dedicated only to the thermostat application.
By means of opto-couplers, safety insulation is implemented between the board and the PC
to allow communication with the GUI when the board is plugged into the line voltage. These
opto-couplers, U3, U4, and U5 are supplied from the USB connector CN1 and the DC-DC
converter J1 in order to not sink current from the capacitive power supply (Appendix B).
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Using the STEVAL-IHT001V2 thermostat kit
3
Using the STEVAL-IHT001V2 thermostat kit
3.1
Thermostat versions
UM1542
The target market of the STEVAL-IHT001V2 kit is represented by low-end to high-end cold
appliances, thus addressing a wide range of the COLD market. In particular, the MCU
firmware is configurable to work in:
●
Basic version: compressor and light bulb control
●
Defrost version: compressor, light bulb and defrost resistor control
●
Air circulation version (default): compressor, light bulb, defrost resistor and fan control
When the target thermostat is selected using the GUI, the gates associated with nonoperating loads are no longer controlled, and remain uncontrolled even if the GUI is
disconnected. To allow again fan or defrost heater control, the user has to re-program the
STM8 MCU using the GUI.
3.2
Loads power
There is no heatsink mounted on the package of ACST610-8FP devices. In this case, the
maximum permanent allowed current is 1.5 A RMS, for an ambient temperature lower than
40 °C (which is usually the highest operating temperature as the thermostat is either inside
the fridge or outside on top, so at room temperature). If the ACST610-8FP must sink a
higher current, or works at a higher temperature, a heatsink can be added. If its case
temperature is kept below 92 °C, these devices can control a 6 A RMS current (as shown in
Fig. 3 of the ACST6 datasheet). Refer to AN533 for further information on thermal
management.
Refer also to AN1354 for more information on single-phase compressor control.
The ACS102-6T, in the TO-92 package, can withstand a 0.2 A RMS permanent current up to
an ambient temperature of 100 °C. The ACS102-6T can drive the common light bulbs or fan
found in the fridge or freezer without any problem. Indeed, a 25 W bulb always sinks a
current lower than 150 mA and ACS102-6T can drive a maximum power fan of 40 W.
The ACS110 can drive a maximum 160 W defrost resistor for an ambient temperature lower
than 40 °C. Indeed, the ACS110 cooling PCB pad of the thermostat kit demonstration board
is cut down to the SOT223 tab size. As shown in fig. 2-2 of the ACS110-7SN datasheet, it
can withstand a 1 A RMS permanent current up to an ambient temperature of 60 °C (with a
copper surface of 5 cm² under the SOT223 tab) and can then drive a 200 W defrost resistor.
14/43
Doc ID 023172 Rev 1
UM1542
3.3
Using the STEVAL-IHT001V2 thermostat kit
Measure points
Figure 5 shows where the test points are placed on the board, while Table 2 gives the
definitions of the measurement points.
Figure 5.
Placement of test points
L
N ZVS GND
VDD
Compressor
Light bulb
Defrost
Fan
AM12241v1
Table 2.
List of test points
Name
3.4
Description
L
Line
N
Neutral
VDD
+5 V - non-insulated power supply (also connected to ACS/ACST cathodes)
GND
GND - non-insulated power supply
ZVS
Zero-voltage signal at STM8 input
TP5
OUT pin of the ACS102 (light bulb)
TP6
OUT pin of the ACST6 (compressor)
TP7
OUT pin of the ACS110 (defrost)
TP8
OUT pin of the ACS102 (fan)
Pulse control
All loads are controlled in full cycle mode by a pulsed gate current. The STM8 MCU senses
both the mains rising and falling edges to synchronize the gate pulse with the mains voltage.
Figure 6 shows the different times useful to understand when the gate current pulses are
applied for the four AC switches (Q1, Q2, Q3, Q4):
●
T1 is the mains voltage / compressor current phase shift. It helps to apply the gate
current pulse just when the Q1 current reaches zero, in order to control the compressor
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Using the STEVAL-IHT001V2 thermostat kit
UM1542
in full cycle mode. A higher delay could be applied to test the compressor in phase
angle mode if required (for example to decrease the power dissipated by the
compressor)
●
T2 is the gate current pulse width for Q2 (defrost resistor)
●
T3 is the gate current pulse width for Q1 (compressor)
●
T4 is the mains voltage / fan current phase shift
●
T5 is the gate current pulse width for Q3 (fan)
●
T6 is the gate current pulse width for Q4 (light bulb)
Figure 6.
Timing definition for gate current pulses
AC Mains
t
ICOMPRESSOR
Gate current (Compressor)
T1
T3
t
Gate current (Defrost)
T2
t
Gate current (Fan)
T4
T5
t
Gate current (Light Bulb)
T6
t
AM12242v1
Gate current pulse delays and widths can be adjusted using the GUI in order to ensure the
right control of loads, otherwise the default parameters shown in Table 3 are used.
Table 3.
Allowable ranges for gate current pulses
Parameter
16/43
Reference Factory setting (ms)
Allowable range
(ms)
Compressor phase shift
T1
0.5
0.1 to 5
Pulse width for defrost resistor control
T2
1
0.1 to 3
Pulse width for compressor control
T3
3
0.1 to 4
Fan phase shift
T4
0.5
0.1 to 5
Pulse width for fan
T5
2
0.1 to 3
Pulse width for light bulb control
T6
5
0.1 to 5
Doc ID 023172 Rev 1
UM1542
Using the STEVAL-IHT001V2 thermostat kit
3.5
Getting started
3.5.1
Jumper configuration for standalone or PC-driven modes
The control side of the thermostat board is supplied by the capacitive power supply (refer to
Section 2.3.3). As for the communication side, it is only supplied by the PC using the USB
connector.
Default jumper positions are indicated in the silkscreen and in Table 4.
Normally, the user must not move jumpers J4, J5, J8, J18 from the default position. They
can be moved only by programming experts in order to modify STM8 firmware for specific
purposes or adaptation to dedicated applications (refer to Appendix F for the procedure to
follow).
Warning:
Table 4.
Please take careful note of the jumper configuration given in
Table 4 before powering up the board, whatever the mode of
operation. Incorrect jumper configuration with a noninsulated power source may result in damage to the PC.
Jumper default configuration in standalone or PC-driven operating mode
Jumper
Mandatory configuration
J4
J5
J8
J18
In order to select the operating mode, switch SW8 must be set as shown in Table 5. Please
note that, once the thermostat board is operating, the operating mode cannot be changed.
In order to change the mode of operation, the user must power off the board, move switch
SW8 and power ON again (Section 3.5.2).
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Using the STEVAL-IHT001V2 thermostat kit
Table 5.
UM1542
Operating mode selector
Operating mode
Description
Standalone mode
PC-driven mode
SW8
3.5.2
Getting started
To operate the STEVA-LIHT001V2 board correctly, follow the steps below given for each
mode.
Standalone mode
1.
Connect the NTC thermistor to the “NTC” connector on the thermostat board (control
side)
2.
Connect the DOOR switch (if an external door switch is going to be used) to the “DOOR
SWITCH” connector on the thermostat board (control side), and set the door switch
embedded on the board to the open position to allow the external switch to drive the
door pin. Otherwise, if no external door switch is used, move the embedded one to the
desired position: open or close. Note that when it is set in the open position, no
temperature setting is allowed (except by using the GUI software in the PC-GUI driven
mode). A closed position is required for temperature setting using the Temp+/Temppush buttons.
3.
Connect the loads on the thermostat board (see Figure 2)
–
18/43
Compressor to “J10” connector
–
Defrost resistor to “J11” connector
–
Fan to “J12” connector
–
Indoor light bulb to “J13” connector.
4.
Ensure that jumpers and switches are set as indicated in Table 4 and 5.
5.
Plug the mains wire into “MAINS” connector. Plug the mains wire into the mains
voltage.
6.
After a few seconds, during which the MCU setup operations and frequency
measurement operation take place:
–
The “on/off” red LED turns on
–
The D7 LED turns on, indicating that medium temperature is set.
–
The compressor and fan switch on if the sensed temperature is above the
temperature order (should be the case if the NTC is at ambient temperature).
–
The light bulb is switched on if the DOOR switch is in an open position, in which
case the fan is switched off.
–
The LED D8 turns on for about a half second during the setup phase, then it is
switched off.
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Using the STEVAL-IHT001V2 thermostat kit
PC GUI driven mode
1.
Repeat steps 1 to 3 of “standalone mode”
2.
Ensure that the jumpers and switches are set as indicated in Table 4 and 5 (PC-driven
mode)
3.
Plug the USB connector into the PC
4.
Plug the mains wire into the “MAINS POWER” connector. Plug the mains wire into the
mains voltage.
5.
After a few seconds during which the MCU setup operations and frequency
measurement operation take place, a popup window indicating that the device has
been recognized appears in the PC. As soon as the popup appears, it is possible to
connect the thermostat board and the thermostat GUI software by pushing the virtual
button “Connect”.
For troubleshooting issues in standalone mode, verify the following:
●
If no LED is ON, check the jumpers (they have to be set as in Table 4, standalone
mode) or replace the fuse
●
If the LEDs seem OK, reset the STM8 microcontroller using button SW1. Otherwise,
unplug the board from the mains, discharge the VDD supply with a short-circuit
between VDD and GND and plug the board back to the mains.
For troubleshooting issues in PC GUI driven mode, verify the following:
3.5.3
●
Ensure that switch SW8 is in the “GUI MODE” position
●
Check that the correct COM port is selected (refer to the GUI “Help” menu for details)
●
Repeat the startup operation, in particular if mains voltage has been turned off,
ensuring that the USB cable is plugged in before the mains wire is connected (i.e. the
interface side must by powered on before the control side).
●
If no popup appears in the PC, just wait a few seconds before connecting the GUI after
the board has been powered ON.
Operating modes
When the board works in standalone mode, control parameters to be considered (pulses
timings, temperatures, fridge version, etc.) are the last ones uploaded in the GUI. If no
parameter has ever been uploaded, the default values are those shown in Table 3, factory
settings. In standalone mode, the temperature order is set by means of the two push buttons
TEMP + and TEMP-, indicated by the five green LEDs (see Figure 2), and the AC loads are
driven according to the order, to the sensed temperature and to the door switch.
In PC GUI mode, the user can upload the control parameters loaded in the STM8 MCU,
check them and eventually modify them. Temperature order is no longer displayed using the
5 LEDs - D4, D5, D7, D8, D9 - but is displayed in the GUI only (virtual LEDs VL, L, M, H,
VH). AC loads can be driven not only according to temperature, but their state can be forced
by the GUI in debug mode (see Section 3.6.3 for details).
The user can put the STM8 in halt mode by holding button SW3 “TEMP -” for 5 s. This lowpower mode can be exited by a single push on SW4, “TEMP+” button. A beep warns at each
halt mode enter/exit.
It should be noted that, since push buttons SW3 and SW4 are disabled when the door is
open, the user cannot enter/exit halt mode if the DOOR switch SW2 (otherwise the external
switch wired to connector J15) is in the open position.
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Using the STEVAL-IHT001V2 thermostat kit
3.5.4
UM1542
Instructions for the GUI software
In order to use the GUI of the STEVAL-IHT001V2 kit, a recent version of Windows (starting
from Windows XP with SP3) must be installed on the user’s computer.
To install the PC software (GUI) tool:
●
Put the companion CD-ROM into the PC
●
Browse the CD-ROM directory to locate the GUI setup executable file
●
Double-click on the GUI setup executable file
●
Follow the instructions as they appear on the screen
An insulated interface is embedded in the board. By means of the STM32 MCU, the user is
able to manage/monitor the control parameters of the thermostat.
For more details please refer to the GUI “Help” menu.
3.6
GUI windows description
3.6.1
Temperature control tab
Choosing one of the temperature orders is done using the “thermostat order” switch position
on the GUI (Figure 7) or using the temp selector push buttons “TEMP+” and “TEMP-” on the
board.
Note:
If “Thermostat order” or “Led temperature” = VL, then “evaporator temperature order” =
“evaporator temperature order 1 - Very Low”
If “Thermostat order” or “Led temperature” = L, then “evaporator temperature order” =
“evaporator temperature order 2 - Low”
If “Thermostat order” or “Led temperature” = M, then “evaporator temperature order” =
“evaporator temperature order 3 - Medium”
If “Thermostat order” or “Led temperature” = H, then “evaporator temperature order” =
“evaporator temperature order 4 - High”
If “Thermostat order” or “Led temperature” = VH, then “evaporator temperature order” =
“evaporator temperature order 5 - Very High”
The value of the five temperature orders and temperature hysteresis has to be set according
to the appliance and the desired cabinet temperature for each operation. They is displayed
through the five virtual LEDs shown in Figure 7. Thermostat order, evaporators temperature
orders and temperature hysteresis are sent and received by clicking on the “Set” or “Get”
buttons, respectively. Note that the default evaporators temperature orders and temperature
hysteresis are given in Appendix G, and can be retrieved by clicking on the “Restore Default”
push button.
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Using the STEVAL-IHT001V2 thermostat kit
Figure 7.
3.6.2
GUI - temperature control tab
Timing control tab
This section (Figure 8) controls the gate current width for the AC switches, the delay to
switch ON the AC switches Q1 (for compressor) and Q3 (for fan), the ZVS delay, the delay to
activate defrost and the defrost duration. These parameters are sent and received by
clicking on the “Set” or “Get” buttons, respectively. Note that the default parameters are
given in Appendix G, and they can be retrieved by clicking on the “Restore Default” push
button.
Figure 8.
GUI - timing control window
The ZVS delay is the delay between the AC mains zero voltage and the detection of this
zero voltage by the MCU in order to synchronize the MCU orders with the AC mains voltage.
The MCU uses the zero-voltage crossing (ZVC) events to synchronize the AC switches gate
current pulses.
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Using the STEVAL-IHT001V2 thermostat kit
3.6.3
UM1542
Force debug
A “force debug” is used to force the AC load state to the control state as defined by the MCU
for easier board validation (Figure 9). In order to control the AC loads, it is necessary to click
on the “Debug Active” button in the “Debug Mode” frame. In this case, the green lights of the
AC load buttons are on if the associated loads are also on. Otherwise, the user can preselect the load to be switched on, before clicking on the “Debug Active” push button, in
which case the buttons corresponding to the pre-selected load become yellow, but this has
no effect until the “Debug Active” button is pushed.
If the debug mode is active (“Debug” push button is lit), then:
Note:
●
Clicking on the “Compressor/Fan” button turns on Q1 and Q3, i.e. the compressor and
fan.
●
Clicking on the “Light Bulb” button turns on Q4, and then the bulb lights up.
●
Clicking on the “Defrost” button turns on Q2, and then the defrost resistor starts to heat.
The defrost and compressor loads cannot be switched on at the same time. Setting defrost
resets compressor, and vice-versa.
The light bulb and fan cannot be switched on at the same time. The fan switches off as soon
as the light bulb switches on.
In order to go back to the “normal” mode, the user must click on the “Debug” button. In this
case, all the virtual button green lights turn off.
Figure 9.
3.6.4
GUI - debug mode frame
Parameter measurements
The GUI is able to get and display the different parameters from the MCU, like the
temperature order, the evaporator temperature, the AC load state, the compressor cycle
information (running period and duty cycle) and the mains frequency.
For more information refer to the “Help” menu of GUI software.
To enable real-time data acquisition, the user must push on the “Start Acquisition” button
(refer to the “Help” menu of the GUI software for more information). The sampling frequency
can be set in the “Options” window.
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3.6.5
Using the STEVAL-IHT001V2 thermostat kit
Saving data
The user can choose to update the STM8 MCU firmware with the timing and temperature
parameters used. A dedicated button allows, in fact, uploading of these parameters.
Otherwise, the STM8 MCU is not updated and default parameters is used for the next
switch-on of the thermostat.
The current parameters can also be saved using the GUI. A .tfs file is available for
uploading. Please note that in this case, the MCU is not programmed with the current
values.
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Conclusion
4
UM1542
Conclusion
This document helps cold appliance designers to use STEVAL-IHT001V2 thermostat kit.
The tool can be used to:
24/43
●
Check the immunity of this ST solution in standalone mode
●
Easily check the appliance efficiency gains by reduction of the hysteresis threshold
●
Define better management of the defrost cycles to improve the overall efficiency
●
Adapt the software - using the GUI - and the hardware for other dedicated designs
(control of different loads (conduction time of the ACS), adapt gate pulse widths and
synchronization, implement potentiometer control, implement light dimming, etc.)
Doc ID 023172 Rev 1
UM1542
Thermal sensor linearization
Appendix A
Thermal sensor linearization
An NTC thermistor is a resistor whose value decreases when its temperature increases.
The thermal law is exponential, as shown in Equation 3:
Equation 3
R NTC (T ) = R0
1 1
B( − )
T T0
To create a simple voltage sensor, it is better to linearize the temperature response using a
constant resistor (R49 in schematic, Appendix B) added in series with the NTC. A voltage
divider is then implemented. The voltage across R49 follows the supply voltage (Vdd)
according to the relationship below:
Equation 4
VS =
R NTC (T )
⋅ Vdd
RNTC (T ) + R 49
To make the relationship of Equation 4 vary linearly, it's sufficient to ensure that the second
order derivative is zero. Equation 5 gives the R49 value to ensure this condition.
Equation 5
2
R49
⎛ d
⎞
R NTC (T ) ⎟
2⋅⎜
dT
⎝
⎠ − R (T )
=
NTC
2
d
R
(
T
)
NTC
dT 2
To linearize the voltage response of the M2020 5 k from EPCOS, between -20 and +5 °C, a
30 kΩ resistor should be chosen for R49.
In this temperature range, VS varies according to Equation 6, for a 5 V supply:
Equation 6
T + 51.84
V l ( T ) ≡ ------------------------16.1943
Figure 10 gives the variation of VS and the linear value given by Equation 6, versus the
temperature sensed by the NTC.
Doc ID 023172 Rev 1
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Thermal sensor linearization
UM1542
Figure 10. Linear voltage in function of the NTC resistor (for a 5 V power supply)
6S 4 6, 4 6
26/43
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Schematics
Schematics
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UM1542
Figure 12. Control side schematic - STM8
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UM1542
Schematics
Figure 13. Interface side schematic
!-V
29/43
Schematics
UM1542
Figure 14. Additional pads schematic
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Doc ID 023172 Rev 1
UM1542
Additional pads
Appendix C
Additional pads
Additional pads were added on the board to allow the user to customize his own board, for
example to replace the two push buttons for temperature order setting with a potentiometer,
add LEDs for further temperature orders, etc. Functionality of additional components is not
implemented. These pads are shown in Figure 14 and 15 and include:
●
One LED replacing the TEMP push button (remove 0 Ω resistor R19, fit LED D11 and
resistor R48).
●
One LED replacing the buzzer (remove 0 Ω resistor R9 and fit LED D12 and resistor
R50)
●
One more push button replacing LED2 (remove R33, fit R22, R45, C35 and push
button SW5).
●
One potentiometer replacing the TEMP+ push button (remove 0 Ω resistor R20, fit R21,
C34, and potentiometer R44).
Figure 15. Placement of additional pads
Additional pads
AM12251v1
Doc ID 023172 Rev 1
31/43
Bill of materials
Appendix D
Table 6.
32/43
UM1542
Bill of materials
BOM
Name
Designation
CN1
Surface-mount USB_mini-B
C1
Capacitor 10 µF 20%
C2
Capacitor 10 nF 20%
C4
Capacitor 4.7 nF 20%
C5
Capacitor 22 pF 20%
C6
Capacitor 22 pF 20%
C7
Capacitor 100 nF 20%
C8
Capacitor 10 nF 20%
C11
Capacitor 100 nF
C12
Capacitor 100 nF
C13
Capacitor 100 nF
C14
Capacitor 100 nF
C19
Capacitor 100 nF
C20
Capacitor 680 nF 20%
C21
Capacitor 1 µF 20%
C22
Capacitor 100 nF
C23
Capacitor 100 nF 16 V 20%
C24
1 nF 16 V 20%
C25
1 nF 16 V 20%
C26
Capacitor 100 nF X2 400VCC/220VCA
C27
Capacitor 2200 µF16 V 20%
C28
Capacitor 10 nF 400VCC/220VCA 10%
C29
Capacitor 1 µF X2 400VCC/220VCA 10%
C30
Capacitor 1 nF 50 V
C31
10 nF 50 V 20%
C32
10 nF 50 V 20%
C33
10 nF 50 V 20%
C34
-
Do not fit
C35
-
Do not fit
C36
1 nF 16 V 20%
C37
1 nF 16 V 20%
C38
2.2 nF
Doc ID 023172 Rev 1
Comment
UM1542
Bill of materials
Table 6.
BOM (continued)
Name
Designation
C39
Capacitor 10 nF 400 VCC/220 VCA 10%
C40
Capacitor 10 nF 400 VCC/220 VCA 10%
C41
Capacitor 10 nF 400 VCC/220 VCA 10%
D1
LED
D2
Zener 5 V 6 0.5 W
D3
Rectifier 1N4148
D4
GREEN_LEDs
D5
GREEN_LEDs
D6
RED_LED
D7
GREEN_LEDs
D8
GREEN_LEDs
D9
GREEN_LEDs
D10
Rectifier 1N4148
D11,D12
Additional LEDs
Do not fit
F1
FUSE
Fuse 8.5 x 8.5 mm 6.3 A 250 V
N/A
FUSEHOLDER
J1
TES 1-0511
DC-DC converter
J2
SWIM_Connector
4w single row vert male smt connector
J3
SWD Connector
10w dual body, SMT micro terminal strip
J4, J5, J8, J18
CON3
Stripline male 3ways
J14
CON3
Terminal Block, nb contacts 3
J10, J11, J12, J13
Connector CON2
Terminal Block, nb contacts 2
J15 J16
Connector CON2
Terminal Block, nb contacts 2
PZ1
Buzzer
BUZZER 4.0 kHz 1-20 V 80DB
Q1
ACST6
Motor switch
Q2
ACST110
Defrost resistor switch
Q3
ACS102-6TA
Fan / light bulb switch
Q4
ACS102-6TA
Fan / light bulb switch
R1
330 Ω
R2
1 MΩ
R3
1 MΩ
R4
10 kΩ
R5
10 kΩ
R6
0
R7
10 kΩ
Doc ID 023172 Rev 1
Comment
33/43
Bill of materials
Table 6.
UM1542
BOM (continued)
Name
Designation
R8
1.5 kΩ
R12
0
R13
0
R17
0
R18
10 kΩ
R19
0
R20
0
R21
0
Do not fit
R22
0
Do not fit
R23
33 Ω (metallic) 1/2 W 1%
R24
56 Ω
R25
47 Ω (metallic) 2 W 1%
R26
150 kΩ (metallic) 1%
R27
150 kΩ (metallic) 1%
R28
100 Ω 5%
R29
100 Ω 5%
R30
90 Ω 5%
R31
90 Ω 5%
R32
350 Ω 5%
R33
350 Ω 5%
R34
350 Ω 5%
R35
350 Ω 5%
R36
50 Ω
R37
350 Ω 5%
R38
30 Ω
R39
10 kΩ
R40
10 kΩ
R41
10 kΩ
R42
300 Ω 5%
R43
300 Ω 5%
R44
Potentiometer
Do not fit
R45, R48, R50
-
Do not fit
R51, R52, R53
56 Ω
R49
30 kΩ 5%
RV1
MOV
34/43
Doc ID 023172 Rev 1
Comment
UM1542
Bill of materials
Table 6.
BOM (continued)
Name
Designation
Comment
SW1
Push button
Reset
SW2
2 Pos slider
Door Switch
SW3
Push button
T- PUSHBUTTON
SW4
Push button
T+ PUSHBUTTON
SW5
Additional push button
Do not fit
SW8
Slider
PC GUI / standalone selector
TP3, TP4, TP5, TP6,
TP7,TP8,TP9, TP10,
TP11
Testing points
U1
STM32F103C6
U2
LD1117/SO
U3,U4,U5
ACPL-072L
U6
STM8S003F3 TSSOP20
U7
USBUF02W6
Y1
8 MHz
N/A
Nylon corner spacer: screw
Doc ID 023172 Rev 1
8 MHz crystal
35/43
Procedure to apply IEC 61000-4-4 burst test
Appendix E
UM1542
Procedure to apply IEC 61000-4-4 burst test
Fast transient voltage tests have been performed, according to the EN 61000-4-4 standard,
on the STEVAL-IHT001V2 board in standalone mode. During the tests, loads were replaced
by incandescent lamps in order to visually detect any load spurious turn-on. Arrangements
have been taken in order to implement tests in agreement with the EN61000-4-4 standard.
Equipment under test was placed on a ground reference plane, insulated from it by an
insulating support 0.1 m ± 0.01 m thick. The NTC (1 m long) (see Figure 16), and all the
cables to the loads were placed on the same insulating support. The power supply to the
EUT was placed on an insulation support 0.1 m above the ground reference plane.
Bursts were directly coupled with equipment.
The test generator was placed directly on, and bonded to, the ground reference plane.
The board was not connected to the earthing system.
Figure 16. Test setup
Thermostat board
NTC
resistor
Bursts
generator
Blocks of ice
Loads
AM12279v1
According to the IEC 61000-4-4, the test signals were characterized by:
●
Polarity: positive/negative
●
Burst duration: 15 ms ± 20% at 5 kHz (Figure 17)
–
36/43
0,75 ms ± 20% at 100 kHz
●
Burst period: 300 ms ± 20%
●
Duration time: 1 minute
●
Applied to: supply voltage line and neutral
Doc ID 023172 Rev 1
UM1542
Procedure to apply IEC 61000-4-4 burst test
The generic graph of a fast transient burst is shown in Figure 17.
Figure 17. General graph of a fast transient/burst
The board withstands up to 4.5 kV and 4.3 kV, positive and negative pulses, respectively at
5 kHz, and up to 3.1 kV, positive and negative pulses, at 100 kHz. At higher voltages, up to
5 kV (at 5 kHz and 100 kHz) temporary disturbance of performance, which ceased after the
fast burst voltage ceased, was detected. The equipment under test recovered its normal
performance, without operator intervention, after the disturbance ceased.
Note:
Because the control firmware loaded in the STEVAL-IHT001V2 board in not optimized for
the IEC 61000-4-4 burst test, separate firmware which implements a smart reset procedure
(without GUI functions) was used to improve the immunity of the board. This firmware is
available on the CD-ROM included with the STEVAL-IHT001V2.
Doc ID 023172 Rev 1
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STM8 program debugging
Appendix F
UM1542
STM8 program debugging
A SWIM connector is present on the board to allow programming/debugging operations.
If an expert user wants to reprogram the STM8, they must follow these procedures:
●
Programming mode procedure:
1.
Unplug the board from the mains voltage
2.
Ensure that the jumpers and switches are set as indicated in Table 7 - programming
mode; in order to provide the MCU with 5 V power supply from USB
3.
Connect the programmer to the SWIM connector (J2 in Figure 5)
4.
Plug in the mini-USB
5.
Continue with usual programming procedures.
Only if an insulated AC source is used to supply the mains voltage, can the board be used in
debug mode, i.e. both the communication side and the control side are supplied by the USB,
but the ACS are supplied by the mains voltage and the board is fully working.
●
Debugging mode procedure:
1.
Plug an insulated AC source to supply STEVAL-IHT001V2 board (J14 header)
2.
Connect the loads on the thermostat board (see Figure 2)
3.
Ensure that the jumpers and switches are set as indicated in Table 7 - debugging
mode; in order to provide the MCU with 5 V power supply from USB
4.
Plug in the mini-USB
5.
Power on the insulated AC source
6.
Continue with usual debugging procedures.
This operating mode is allowed only for expert users.
Warning:
Table 7.
Please take careful note of the jumper configuration given in
Table 7 before powering up the board, whatever the mode of
operation. Incorrect jumper configuration with a noninsulated power source may result in damage to the PC.
Jumper configuration in programming and debugging modes
Jumper
Programming mode Debugging mode(1)
J4
J5
38/43
Doc ID 023172 Rev 1
Description
UM1542
STM8 program debugging
Table 7.
Jumper configuration in programming and debugging modes
Jumper
Programming mode Debugging mode(1)
Description
J8
(2)
J18
1. This debugging mode refers to the possibility to potentially debug a new different firmware uploaded in the
STM8 microcontroller. Do not mistake with “Debug mode” described in Section 3.6.3, since it means an
operating mode offered by the PC-GUI software, nothing to do with the debugging of firmware.
2. Only if an insulated power source is used.
Doc ID 023172 Rev 1
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PC interface parameters description
Appendix G
UM1542
PC interface parameters description
Output in the table below is defined as the information sent by the STM8S MCU to the
STM32, and input is the contrary.
Table 8.
PC interface parameters
Software type
Unit
Factory
setting
Allowable
range
Setting step
Temperature hysteresis
Input/output
°C
4
0.5 to 20
0.1
Evaporator temperature
Output
°C
N/A
-40 to +40
Evaporator temperature order 1
Input/output
°C
-5
-40 to 10
0.5
Evaporator temperature order 2
Input/output
°C
-12
-40 to 10
0.5
Evaporator temperature order 3
Input/output
°C
-20
-40 to 10
0.5
Evaporator temperature order 4
Input/output
°C
-28
-40 to 10
0.5
Evaporator temperature order 5
Input/output
°C
-36
-40 to 10
0.5
Compressor phase shift
Input/output
ms
0.5
0.1 to 5
0.1
Gate current pulse width
for compressor control
Input/output
ms
3
0.1 to 4
0.1
Gate current pulse width
for bulb control
Input/output
ms
5
0.1 to 5
0.1
Gate current pulse width
for defrost resistor control
Input/output
ms
1
0.1 to 3
0.1
Gate current pulse width for fan
Input/output
ms
2
0.1 to 3
0.1
Fan phase shift
Input/output
ms
0.5
0.1 to 5
0.1
Defrost activation delay
Input/output
Hours and
minutes
8
1 to 99
10’
Defrost duration
Input/output
Minutes and
seconds
20
1 to 60
10’
ZVS delay
Input/output
µs
50
5 to 255
5
Output
Hz
N/A
50 / 60
Parameter
Line frequency
40/43
Doc ID 023172 Rev 1
UM1542
Capacitor value according to country
Appendix H
Capacitor value according to country
Table 9 indicates the capacitor value for a 30 mA average current for typical application case
(nominal capacitor value, nominal RMS line voltage) versus different AC mains and
frequency values used in different countries.
Moreover, the typical and minimal (nominal capacitor value -10%, minimum RMS line
voltage) output DC current capabilities are included for information.
Table 9.
C29 capacitor value according to the country
Typical RMS
Minimum
Country
voltage
RMS voltage
Frequency
C29
capacitor
Output DC current
Min. output DC current
for typical
capabilities for worst
application
application case
conditions
Japan
100 V
90 V
50/60 Hz
2.2 µF
31.1 mA
25.2 mA
USA
120 V
100
60 Hz
1.5 µF
30.5 mA
22.9 mA
Brazil,
Mexico
120 V to
240 V
102 V to
204 V
50/60 Hz
2.2 µF
37.3 mA
28.5 mA
Europe,
China,
Korea,
Australia
220 V to
240 V
187 V to
204 V
50/60 Hz
1 µF
31.1 mA
23.8 mA
Doc ID 023172 Rev 1
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Revision history
UM1542
Revision history
Table 10.
42/43
Document revision history
Date
Revision
10-Sep-2012
1
Changes
Initial release.
Doc ID 023172 Rev 1
UM1542
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