Title of Invention	METHOD FOR STORAGE OF INDIVIDUAL DATA ITEMS OF A LOW-VOLTAGE CIRCUIT BREAKER
Abstract	The invention relates to a method for storage of calibration data as individual data items of a low-voltage circuit breaker with a microcontroller tripping device, comprising: filing memory cells of a one time programmable memory of the microcontroller with a program code written to it in a programming cycle; executing a test run of the program code; determining calibration data of the tripping device in the test run; filling memory cells of the memory, which are not filled with the program code, with the calibration data in a first further programming cycle; and reading the most recent of the stored calibration data when running the program code to operate the tripping device.

Title of Invention

METHOD FOR STORAGE OF INDIVIDUAL DATA ITEMS OF A LOW-VOLTAGE CIRCUIT BREAKER

Abstract

The invention relates to a method for storage of calibration data as individual data items of a low-voltage circuit breaker with a microcontroller tripping device, comprising: filing memory cells of a one time programmable memory of the microcontroller with a program code written to it in a programming cycle; executing a test run of the program code; determining calibration data of the tripping device in the test run; filling memory cells of the memory, which are not filled with the program code, with the calibration data in a first further programming cycle; and reading the most recent of the stored calibration data when running the program code to operate the tripping device.

Full Text	Description Method for storage of individual data items of a low-voltage circuit breaker The invention relates to a method for storage of individual data items of a low-voltage circuit breaker with a microcontroller tripping device. Modern low-voltage circuit breakers are equipped with an electronic tripping device, and contain a programmable microcontroller. The tripping device can be used for a plurality of low-voltage circuit breakers with different ratings, and can be matched to the respective circuit breaker type. For this purpose, the tripping device requires type data as well as other individual data items about the circuit breaker, that is to say calibration data describing specific hardware data, calibration data for analog measurement inputs of the microcontroller, as well as the serial number and identification number of the circuit breaker, by means of- which each individual breaker can be identified. This data should be stored as safely and invariably as possible. One normal solution is for this data to be stored in a rewritable information memory, for example flash-EEPROM, or a serial EEPROM, and to be read by the software as required. The linking process between them often involves slow serial data buses such as I2C or SPI. This reading process has a negative influence on the time taken for complete activation. DE 19 8 45 799 A1 discloses the information memory being integrated in the plug-in apparatus of a connecting line between a current transformer and an overcurrent release. Since this requires a special plug, DE 100 19 092 A1 has proposed for an EEPROM to be inserted directly in the connecting line. Since the connecting line is subject to the interference influence of electrical fields in the circuit breaker, DE 102 21 572 Al has proposed that the information memory be accommodated physically separately from the overcurrent release in the circuit breaker, and that it be operated by means of a write protection system. The write protection can be activated either via the overcurrent release and a data bus, or via a special programmer (DE 102 21 579 A1). According to DE 102 21 571 A1, activation and deactivation are possible by varying the supply voltage, for example changing the polarity of the supply voltage to the information memory. EP 0880159 describes a switch having switching position carrying the current to be limited, a switching lock operating with a movable contact for this position, a short circuit current trip with a coil carrying the current and an armature which acts on the movable contact directly or via the switch lock. An electronic overcurrent trip interacts with the switch lock. A current sensor detects the current and provides control signals to the overcurrent trip, which is powered from the current. The overcurrent rip contains a data processor with a memory for holding switch specific technical data entered during manufacture, e.g. the trip characteristic. The current sensor has an essentially linear characteristic as far as a threshold defined by the response level of the short circuit trip.; The short circuit trip can be loaded with operating currents between 0.1 Amps and an upper limit or between a lower limit and 180 Amps. EP0151147 (A1) teaches a conditional access system for over-air transmission and reception of scrambled television signals to improve the reliability of the reception by transmitting a key signal for use in descrambling the television signal in a block of information which is itself encyphered by the key signal. On reception, the receiver after decyphering of the block of information compares the key signal recovered from the block with the key signal provided at the receiver for decyphering the block. Descrambling will only be allowed if comparison shows the two key signals to be the same. The system also provides for information relating to the credit status of each user to be transmitted over-air. In oder to ensure rapid operation, the credit status signal is sent repeatedly and a further signal is appended which is used at the receiver to prevent repeated accumulation of credit. An alternative arrangement is for the transmitter to transmit a signal indicative of the total sum of credit ever purchased by a user and for the user's receiver to include a counter for accumulating ail charges for programs viewed. A simple comparison between the two signals is sufficient to establish whether or not the viewer may view a program. The information memory with a write protection system has the disadvantages that the writing/reading cycle can be influenced by electromagnetic interference fields, and that data losses can occur in the event of an inadvertent change from the read mode to the write mode. The invention is based on the object of specifying a method for storage of individual data items of a low-voltage circuit breaker, by means of which the data is quickly available and is reliably protected against unauthorized access and data losses. According to the invention, this object is achieved by the features of claim 1. Expedient refinements are the subject matter of the dependent claims. Accordingly, ROM memory cells which are not filled with program code in the ROM of the microcontroller are filled with the individual data items (calibration data, identification data) of the low- voltage circuit breaker. The free memory cells in the ROM are expediently filled with the individual data items of the circuit breaker in a further programming cycle after the programming of the program code in the ROM of the microcontroller. The further programming cycle is carried out by making use of the physical characteristics of the memory cells that each bit cell can be reprogrammed from the initial value "1" to "0", but cannot be reset to the original state. Memory cells which are not programmed in the first run can therefore still be written to in a second or further run. If required, a plurality of areas of the OTP-ROM can be defined for subsequent programming cycles, so that the data can also be updated, with the respective up-to-date data being accessed. The advantage of the method is that no additional memory module is required for the calibration data, from the software point of view, the data is directly available and can be used without any time loss; it need not be read from the external memory via slow data buses before it can be used, the data is better protected against unauthorized access. External reading or modification of the data is feasible only with a very high degree of technical effort, if it is not completely impossible, depending on the microcontroller. The method will be explained in more detail with reference to an exemplary embodiment and, in the associated drawings: Figure 1 shows a flowchart for storage of a calibration value, and Figure 2 shows a flowchart for reading of a calibration value. The OTP-ROM first of all has a program code written to it in a first programming cycle, containing the functions of the overcurrent release. The individual memory cells in the OTP-ROM can be written to only once (one-time programmable). In accordance with the method according to the invention, even in this first programming cycle, data items, for example identification data for the circuit breaker, can also be entered in memory cells which have not been filled by the program code, although this is expediently done in a further programming cycle. Correct interaction of the overcurrent release with the current transformers in a power supply system that is being monitored requires, for example, that the microcontroller for the overcurrent release processes the current signals supplied to it using conversion factors, depending on the rated current and the accuracy of the current transformer, the nature of the circuit breaker and further factors. These conversion factors can be determined by a test run of the circuit breaker, for which purpose the program code (firmware) must, however, also be operable. The conversion factors determined in the test run form calibration data, which must be stored in an information memory of the circuit breaker. An unfilled area of the memory cell in the OTP-ROM is used for this purpose, according to the invention. Figure 1 shows the process of determining and storing a single calibration value. The determined calibration value is read in a second programming cycle into the first free memory cells in the OTP-ROM. At the same time, identification data can also be read in as well here. The calibration value is then checked once again and, if necessary, is entered as a corrected value in the next free memory cell. The process can be repeated until an appropriate calibration value is available. When reading calibration values, the program then accesses the respectively most recent of the stored calibration values, as shown in a further flowchart in Figure 2. If the program finds an unoccupied memory cell, that is to say a memory cell that has not been changed (no "F"), then it reads the previous memory cell, which contains the appropriate calibration value. If required, one or else a plurality of memory areas can be defined in the OTP-ROM for subsequent programming cycles, to which up-to-date data can be read again later, or identification data is entered for the first time which, for example, can be defined only before delivery of the circuit breaker. Even in the case of a circuit breaker which is already in use, it may be necessary to update the individual data items. By way of example, replacement of current transformers may result in the need to change the data items. During operation, the microcontroller accesses the stored data, that is to say it processes the current signal supplied from the current transformers together with the stored data items and decides to carry out tripping without any delay in the event of short-circuit currents, delayed tripping in the event of overcurrents, and the production of appropriate messages. The program code must be programmed such that it always accesses the respective up-to-date data. WE CLAIM : 1. A method for storage of calibration data as individual data items of a low- voltage circuit breaker with a microcontroller tripping device, comprising: - filing memory cells of a one time programmable memory of the microcontroller with a program code written to it in a programming cycle; - executing a test run of the program code; determining calibration data of the tripping device in the test run; - filling memory cells of the memory, which are not filled with the program code, with the calibration data in a first further programming cycle; - and reading the most recent of the stored calibration data when running the program code to operate the tripping device. 2. The method as claimed in claim 1, comprising : repeated running of the program code to determine at least one of corrected calibration data and corrected individual data and filing memory cells of the memory, which are not filled with the corrected calibration data/individual data in a second further programming cycle. 3. The method as claimed in claim 1, wherein a plurality of areas of the memory are defined for subsequent programming cycles for filing with the individual data items of the low-voltage circuit breaker. ABSTRACT TITLE "METHOD FOR STORAGE OF INDIVIDUAL DATA ITEMS OF A LOW-VOLTAGE CIRCUIT BREAKER" The invention relates to a method for storage of calibration data as individual data items of a low-voltage circuit breaker with a microcontroller tripping device, comprising: filing memory cells of a one time programmable memory of the microcontroller with a program code written to it in a programming cycle; executing a test run of the program code; determining calibration data of the tripping device in the test run; filling memory cells of the memory, which are not filled with the program code, with the calibration data in a first further programming cycle; and reading the most recent of the stored calibration data when running the program code to operate the tripping device.

Full Text

Description
Method for storage of individual data items of a low-voltage
circuit breaker
The invention relates to a method for storage of individual
data items of a low-voltage circuit breaker with a
microcontroller tripping device.
Modern low-voltage circuit breakers are equipped with an
electronic tripping device, and contain a programmable
microcontroller. The tripping device can be used for a
plurality of low-voltage circuit breakers with different
ratings, and can be matched to the respective circuit breaker
type. For this purpose, the tripping device requires type data
as well as other individual data items about the circuit
breaker, that is to say calibration data describing specific
hardware data, calibration data for analog measurement inputs
of the microcontroller, as well as the serial number and
identification number of the circuit breaker, by means of- which
each individual breaker can be identified. This data should be
stored as safely and invariably as possible.
One normal solution is for this data to be stored in a
rewritable information memory, for example flash-EEPROM, or a
serial EEPROM, and to be read by the software as required. The
linking process between them often involves slow serial data
buses such as I2C or SPI. This reading process has a negative
influence on the time taken for complete activation.
DE 19 8 45 799 A1 discloses the information memory being
integrated in the plug-in apparatus of a connecting line
between a current transformer and an overcurrent release.

Since this requires a special plug, DE 100 19 092 A1 has proposed for an EEPROM to be
inserted directly in the connecting line. Since the connecting line is subject to the
interference influence of electrical fields in the circuit breaker, DE 102 21 572 Al has
proposed that the information memory be accommodated physically separately from the
overcurrent release in the circuit breaker, and that it be operated by means of a write
protection system. The write protection can be activated either via the overcurrent
release and a data bus, or via a special programmer (DE 102 21 579 A1). According to
DE 102 21 571 A1, activation and deactivation are possible by varying the supply
voltage, for example changing the polarity of the supply voltage to the information
memory.
EP 0880159 describes a switch having switching position carrying the current to be
limited, a switching lock operating with a movable contact for this position, a short
circuit current trip with a coil carrying the current and an armature which acts on the
movable contact directly or via the switch lock. An electronic overcurrent trip interacts
with the switch lock. A current sensor detects the current and provides control signals to
the overcurrent trip, which is powered from the current. The overcurrent rip contains a
data processor with a memory for holding switch specific technical data entered during
manufacture, e.g. the trip characteristic. The current sensor has an essentially linear
characteristic as far as a threshold defined by the response level of the short circuit trip.;
The short circuit trip can be loaded with operating currents between 0.1 Amps and an
upper limit or between a lower limit and 180 Amps.
EP0151147 (A1) teaches a conditional access system for over-air transmission and
reception of scrambled television signals to improve the reliability of the reception by
transmitting a key signal for use in descrambling the television signal in a block of
information which is itself encyphered by the key signal. On reception, the receiver after
decyphering of the block of information compares the key signal recovered from the
block with the key signal provided at the receiver for decyphering the block.

Descrambling will only be allowed if comparison shows the two key signals to be the
same. The system also provides for information relating to the credit status of each user
to be transmitted over-air. In oder to ensure rapid operation, the credit status signal is
sent repeatedly and a further signal is appended which is used at the receiver to prevent
repeated accumulation of credit. An alternative arrangement is for the transmitter to
transmit a signal indicative of the total sum of credit ever purchased by a user and for
the user's receiver to include a counter for accumulating ail charges for programs
viewed. A simple comparison between the two signals is sufficient to establish whether
or not the viewer may view a program.
The information memory with a write protection system has the disadvantages that the
writing/reading cycle can be influenced by electromagnetic interference fields, and that
data losses can occur in the event of an inadvertent change from the read mode to the
write mode.
The invention is based on the object of specifying a method for storage of individual
data items of a low-voltage circuit breaker, by means of which the data is quickly
available and is reliably protected against unauthorized access and data losses.
According to the invention, this object is achieved by the features of claim 1. Expedient
refinements are the subject matter of the dependent claims.
Accordingly, ROM memory cells which are not filled with program code in the ROM of
the microcontroller are filled with the individual

data items (calibration data, identification data) of the low-
voltage circuit breaker.
The free memory cells in the ROM are expediently filled with
the individual data items of the circuit breaker in a further
programming cycle after the programming of the program code in
the ROM of the microcontroller.
The further programming cycle is carried out by making use of
the physical characteristics of the memory cells that each bit
cell can be reprogrammed from the initial value "1" to "0", but
cannot be reset to the original state. Memory cells which are
not programmed in the first run can therefore still be written
to in a second or further run.
If required, a plurality of areas of the OTP-ROM can be defined
for subsequent programming cycles, so that the data can also be
updated, with the respective up-to-date data being accessed.
The advantage of the method is that
no additional memory module is required for the
calibration data,
from the software point of view, the data is directly
available and can be used without any time loss; it need
not be read from the external memory via slow data buses
before it can be used,
the data is better protected against unauthorized access.
External reading or modification of the data is

feasible only with a very high degree of technical effort,
if it is not completely impossible, depending on the
microcontroller.
The method will be explained in more detail with reference to
an exemplary embodiment and, in the associated drawings:
Figure 1 shows a flowchart for storage of a calibration value,
and
Figure 2 shows a flowchart for reading of a calibration value.
The OTP-ROM first of all has a program code written to it in a
first programming cycle, containing the functions of the
overcurrent release. The individual memory cells in the OTP-ROM
can be written to only once (one-time programmable). In
accordance with the method according to the invention, even in
this first programming cycle, data items, for example
identification data for the circuit breaker, can also be
entered in memory cells which have not been filled by the
program code, although this is expediently done in a further
programming cycle.
Correct interaction of the overcurrent release with the current
transformers in a power supply system that is being monitored
requires, for example, that the microcontroller for the
overcurrent release processes the current signals supplied to
it using conversion factors, depending on the rated current and
the accuracy of the current transformer, the nature of the
circuit breaker and further factors. These conversion factors
can be determined by a test run of the circuit breaker, for
which purpose the program code (firmware) must, however, also
be operable. The conversion factors determined in the test run
form calibration data, which must be stored in an information
memory

of the circuit breaker. An unfilled area of the memory cell in
the OTP-ROM is used for this purpose, according to the
invention.
Figure 1 shows the process of determining and storing a single
calibration value. The determined calibration value is read in
a second programming cycle into the first free memory cells in
the OTP-ROM. At the same time, identification data can also be
read in as well here. The calibration value is then checked
once again and, if necessary, is entered as a corrected value
in the next free memory cell. The process can be repeated until
an appropriate calibration value is available.
When reading calibration values, the program then accesses the
respectively most recent of the stored calibration values, as
shown in a further flowchart in Figure 2. If the program finds
an unoccupied memory cell, that is to say a memory cell that
has not been changed (no "F"), then it reads the previous
memory cell, which contains the appropriate calibration value.
If required, one or else a plurality of memory areas can be
defined in the OTP-ROM for subsequent programming cycles, to
which up-to-date data can be read again later, or
identification data is entered for the first time which, for
example, can be defined only before delivery of the circuit
breaker. Even in the case of a circuit breaker which is already
in use, it may be necessary to update the individual data
items. By way of example, replacement of current transformers
may result in the need to change the data items.
During operation, the microcontroller accesses the stored data,
that is to say it processes the current signal supplied from
the current transformers together with the stored

data items and decides to carry out tripping without any delay
in the event of short-circuit currents, delayed tripping in the
event of overcurrents, and the production of appropriate
messages. The program code must be programmed such that it
always accesses the respective up-to-date data.

WE CLAIM :
1. A method for storage of calibration data as individual data items of a low-
voltage circuit breaker with a microcontroller tripping device, comprising:
- filing memory cells of a one time programmable memory of the
microcontroller with a program code written to it in a programming cycle;
- executing a test run of the program code; determining calibration data of
the tripping device in the test run;
- filling memory cells of the memory, which are not filled with the program
code, with the calibration data in a first further programming cycle;
- and reading the most recent of the stored calibration data when running
the program code to operate the tripping device.
2. The method as claimed in claim 1, comprising :
repeated running of the program code to determine at least one of
corrected calibration data and corrected individual data and filing memory
cells of the memory, which are not filled with the corrected calibration
data/individual data in a second further programming cycle.

3. The method as claimed in claim 1, wherein a plurality of areas of the
memory are defined for subsequent programming cycles for filing with the
individual data items of the low-voltage circuit breaker.

ABSTRACT

TITLE "METHOD FOR STORAGE OF INDIVIDUAL DATA ITEMS OF
A LOW-VOLTAGE CIRCUIT BREAKER"
The invention relates to a method for storage of calibration data as
individual data items of a low-voltage circuit breaker with a
microcontroller tripping device, comprising: filing memory cells of a one
time programmable memory of the microcontroller with a program code
written to it in a programming cycle; executing a test run of the program
code; determining calibration data of the tripping device in the test run;
filling memory cells of the memory, which are not filled with the program
code, with the calibration data in a first further programming cycle; and
reading the most recent of the stored calibration data when running the
program code to operate the tripping device.

METHOD FOR STORAGE OF INDIVIDUAL DATA ITEMS OF A LOW-VOLTAGE CIRCUIT BREAKER

Documents:

Inventors:

PCT Conventions: