EP3184952A1

EP3184952A1 - Communication method between anti-theft devices of the fog-generating type, device and system which use such method

Info

Publication number: EP3184952A1
Application number: EP16002433.7A
Authority: EP
Inventors: Alberto Mori; Mauro Lombardo
Original assignee: UR Fog SRL
Current assignee: UR Fog SRL
Priority date: 2015-12-24
Filing date: 2016-11-16
Publication date: 2017-06-28
Anticipated expiration: 2036-11-16
Also published as: ITUB20159568A1; DK3184952T3; EP3184952B1

Abstract

A method is described for transmitting a message between anti-theft devices of the fog-generating type through a serial channel, wherein the message comprises an orderly sequence of characters with start-of-sequence and end-of-sequence marker characters, the start-of-sequence marker being followed by characters which are the data fields of the message, the method comprising a step of sending the marker character and the characters composing the message data fields to the anti-theft device; after some checking steps, a step of interpreting and executing the message by the anti-theft device; and a step of issuing a reply by the anti-theft device.

Description

The present invention refers to a communication method between anti-theft devices of the fog-generating type, to a device and to a system which use such method. In particular, the invention relates to a method for transmitting messages or sentences between anti-theft devices of the fog-generating type for remotely controlling the main functions of the fog-generating device, arming and shooting included, to a device which uses such method, and to a system comprising devices which use such method.
Anti-theft devices of the fog-generating type are known in the art, and they allow a local checking of the arming and shooting functions of the fog-generating device.
Such devices however have the inconvenience that they do not allow remotely controlling the main functions of the device, arming and shooting included.
Object of the present invention is solving the above prior art problems, by providing a method for transmitting messages between anti-theft devices of the fog-generating type which allows remotely controlling the main functions of the fog-generating device.
The above and other objects and advantages of the invention, as will appear from the following description, are obtained with a method for transmitting messages or sentences between anti-theft devices of the fog-generating type as claimed in Claim 1. Preferred embodiments and non-trivial variations of the present invention are claimed in the dependent Claims.
It is intended that all enclosed claims are an integral part of the present disclosure.
It will be immediately obvious that numerous variations and modifications (for example related to shape, sizes, arrangements and parts with equivalent functionality) could be made to what is described, without departing from the scope of the invention as appears from the enclosed claims.
The present invention will be better described by some preferred embodiments thereof, given as a non-limiting example, with reference to the enclosed drawings, in which:

Figure 1 is a perspective view of part of an interfacing circuit of the anti-theft device of the fog-generating type of the invention.

With reference to the Figure, a non-limiting embodiment of the method for transmitting messages or sentence between anti-theft devices of the fog-generating type is shown and described, for remotely controlling the main functions of the fog-generating device, together with the device which uses such method, and the system comprising devices which use such method according to the present invention.
The communication protocol or method of the present invention is adapted to allow remotely controlling the main functions of a fog-generating device, arming and shooting included.
The anti-theft device of the fog-generating type, or fog-generating device, to be controlled by means of the method (protocol) for transmitting messages of the invention comprises a control board with a microcontroller of a known type, connected to a remote board, for example through a flat cable. The remote board can be an add-on card installed in the fog-generating device and in turn connected to a second anti-theft device, for example an alarm device, a computer, etc. or can be installed in the second anti-theft device and connected to the fog-generating device.
The anti-theft device of the fog-generating type, the remote board and the second anti-theft device are the anti-theft system of the fog-generating type of the invention.
Preferably, the control board of the fog-generating device comprises a memory of the flash type for storing static variables in a non-volatile way, as will be described below in detail.
Figura 1 shows an example of a diagram of the interfacing hardware of the remote board.
Preferably, the communication between the control board of the fog-generating device and the remote board, using the communication protocol or method of the invention, occurs through a serial channel with 3 wires (Tx, Rx, GND) with CMOS 0-5V levels, standard RS232 format, 1 start but, 8 data bits, 1 stop bit, no parity, at the rate of 4800 bit/s.
For example, the connector on board the control board of the fog-generating device is the P/N 690367280876, manufactured by Wurth Elektronik, or the same signals are included on a standard pin-header with 2.54 mm pitch.
Preferably, the remote or add-on board is made according to the following minimum specifications:

operating temperature range: -40 ÷ +85 °C;
FR4 support with TG>=170°C;
solder resist on both external faces;
silk-screen printing on components side with indication of pin 1 for every connector;
lead-free RoHS technology;
compliance with EC and EMC standards recalled in the certification of the fog-generating device or of the device in which the remote or add-on board will have to be installed.

Within a maximum time of 10 s from the time in which the voltage VCC50 drops below 3.0 V, the add-on board will have to place itself in reduced consumption mode (preferably null and anyway never greater than 10 µA) to avoid discharging the internal battery. The full functionality will have to be restored within 1 s from the return of the VCC50 voltage to values greater than 4.0 V.
Herein below, the syntax of the communication protocol or method of the invention is described.
Every message or sentence of the communication protocol or method starts with character '$' (start-of-sequence marker, ASCII 0x24) and ends with CR (Carriage Return) character (end-of-sequence marker, ASCII 0x0D
The start-of-sequence marker is followed by the data fields of the message separated by commas.
At the end of the last data field, there is an asterisk followed by 4 hexadecimal characters (herein below designated with "*hhhh") which represent the value in ASCII-HEX coding of the CRC16 computed on all characters included between '$' and '*' (extremes included). A computation example of the CRC 16 is included below.
In order to facilitate the interfacing with low-end microcontrollers, the maximum length of the whole sentence, from the start-of-sequence marker to the Carriage Return character (included) cannot exceed 32 characters.
The process for acquiring a message or sentence starts with the reception of character '$' and ends with the reception of character Carriage Return (ASCII 0x0D); the process is ended also if an error is detected in the input flow as violation of one or more of the following rules:

1. at least one character inside a field does not fall within the range of allowed values;
2. the sentence has a global length greater than 32 characters (including 0x0D).

If the reception of a sentence prematurely ends, a $NACK message will be issued and the state machine will go back in stand-by waiting for a new character '$'.
In case of correctly ended reception with the end-of-sequence marker, the CRC16 will be verified and, without errors, the sentence will be interpreted and executed by the microcontroller of the fog-generating device. At the end of the execution, a reply will always be issued, and depends on the type of processed sentence. If an error is detected on the CRC16, the sentence will be wholly discarded and the $NACK message will be issued.
In general, issuing of a $NACK message can also occur if a correctly received and interpreted sentence cannot be wholly executed by the fog-generating device due to any reason. Vice versa, the reception of a reply message different from $NACK is an enough condition to state that a given sentence has been correctly received and executed.
A computation example of CRC16 is given below, implemented by using the generating polynomial x¹⁶+x¹⁵+x²+1, with starting value 0xFFFF and final inversion.
As an example, a function in C language is included, which returns the CRC16 as defined, computing it on all data of an input vector:

// CRC16-ANSI function. Generator polynomial x^16+x^15+x^2+1
     // starting value: 0xFFFF
     uint16 ComputeCRC16 (uint8 *pvector, uint8 dim)
     {
      uint16 nCrc, nCarry;
      uint8 i, j;
      // frame checking
      nCrc=0xFFFF;
      for (i=0;i<dim;i++)
      {
        nCre=nCrc^pvector[i] ;
        for (j=0; j<8; j++)
        (
          nCarry=nCrc&0x0001;
          nCrc>>=1;
          if (nCarry) nCrc^=0xA001;
        }
      }
      j=(uint8) (nCrc>>8);
      nCrc=(nCrc<<8) + (uint16) j;
      return (∼nCrc) ;
     }

The mode for managing the connection between anti-theft device of the fog-generating type and remote board will now be described.

To determine the occurrence of the connection with the remote board, the control board of the fog-generating device will have to correctly receive at least one sentence every 60 s. After this time without correctly received sentences, the control board of the fog-generating device will deem the serial connection dropped with the remote board and will set itself to a stand-alone operating mode, restoring to their starting values all data structures modified in a volatile way by the remote board, while the static variables stored in the flash memory will keep their last value as set, as will be explained below in more detail.

Moreover, if the remote board has nothing to communicate, it can verify the correct functionality of the bidirectional serial channel by sending a suitably pre-arranged $NOP message, and afterwards verifying the presence of a $ACK reply message from the control board of the fog-generating device.

To avoid overloading the microcontroller of the fog-generating device, it is preferable to limit the communication to a maximum of 2 queries per second.

The remote board, once having sent a sentence, will have to wait for at least a time equal to the maximum processing time, before starting a new transaction.

If, after the maximum processing time, no reply has been received, it is necessary to assume that the remote control board is not synchronized any more with the fog-generating device. This condition can be due to different reasons, among which the lack of compliance with indications contained in the present document, a spurious communication disturbance or a bug in the internal stack firmware of the fog-generating device.

Whichever the reason, it is necessary to proceed with a re-synchronization in order to be able to obtain again the remote control of the fog-generating device. The steps to be followed for performing the re-synchronization are the following:

1. stop every transmission on the serial channel;
2. wait for a time not shorter than 80 s to force the input of the fog-generating device in stand-alone mode;
3. restore the communication by sending a new $REMOTE message.

Under the stand-alone operating mode, the fog-generating device sends on the serial channel some pieces of information used during the end-of-line testing steps.

These pieces of information must not be used in any way by the remote board, because they can be changed or removed without any forewarning. The absence of the start-of-sequence marker from data sent under this mode must therefore be guaranteed.

Herein below, a list of input messages in the control board of the fog-generating device is included, according to the communication protocol or method of the invention.

$REMOTE*hhhh

The $REMOTE*hhhh message arranges the serial interface for the remote control of the fog-generating device. Upon power-on, the fog-generating device sends on the serial interface some information about its own internal status: these data are used during the testing and/or failure search procedures. Under this status, the microcontroller of the fog-generating device responds only to the $REMOTE message: all other data sent on the serial interface are ignored.

If it is sent in online mode, the $REMOTE message, in addition to sending the protocol version number ($VER message), re-initializes all data structures and variables linked to the protocol and stored in a volatile way.

In the remote control mode, the actual arming and shooting signals are derived respectively from a logic AND operation and a logic OR operation between local and remote commands.

The actual arming status of the fog-generating device is determined by the logic AND operation between the remote signal and the local arming input present aboard the card.

The shooting signal is determined by the logic OR operation between the remote signal and a local signal.

The machine sends, in reply to this command, the $VER or $NACK message in case of error.

$SHOOT!*hhhh

The $SHOOT!*hhhh message starts a shooting if the fog-generating device is armed, with bottles enough filled-in, at a temperature and no failures or errors have been detectd. The necessary conditions for shooting depend on model and typology of the affected fog-generating device, but are wholly summarized in a system ready variable, which will be described below in Table 4, whose value is always machine independent.

It returns as reply a $ACK or $NACK message in case of error.

$TANKRESET*hhhh

The $TANKRESET*hhhh message performs a bottle reset operation following a press on the suitable push-button on the board of the fog-generating device. It is advisable to use this function with extreme care, avoiding to send the command without a corresponding physical and actual operation of replacement of empty bottles.

It returns as reply a $ACK or $NACK message in case of error.

$NOP*hhhh

The $NOP*hhhh message does nothing. The remote board can use it as heartbeat to keep the connection active, if there is nothing to communicate.

It returns as reply a $ACK or $NACK message in case of error.

$READ,name*hhhh

The $READ,name*hhhh message reads the value of an internal variable stored in the control board of the fog-generating device according to Table 1 (included below) in which some examples are listed for allowed values for the name field.

It returns as reply a $DATA or $NACK message in case of error.

$WRITE,name,value*hhhh

The $WRITE,name,value*hhhh message sets the value of an internal variable stored in the control board of the fog-generating device according to Table 1 in which some examples are listed for allowed values for the name and value fields.

It returns as reply a $ACK or $NACK message in case of error.

Herein below, a list of messages output by the control board of the fog-generating device according to the communication protocol or method of the invention are included.

$ACK*hhhh

The $ACK*hhhh message is issued following the correct reception and execution of a sentence should this not require the generation of a different reply.

$NACK*hhhh

The $NACK*hhhh message is issued following an error in the reception or execution of any sentence.

$DATA,name,value*hhhh

The $DATA,name,value*hhhh message is issued by the fog-generating device following a $READ message and returns the value of an internal variable as per Table 1.

$VER,abc*hhhh

With the $VER,abc*hhhh message, the fog-generating device communicates the version number of the current implementation of the protocol.

Preferably, the syntax of $REMOTE and $VER messages remains unchanged in all possible following versions of the protocol.

For example, digit a can assume a value included between 'A' and 'Z' while digits b, c can assume values in the '0'...'9' range. In this way, it is possible to represent a version number from "A00" to "Z99".

In addition to allowing the shooting activation by a remote control unit, the communication method of the present invention allows reading and/or modifying a series of internal variables used for managing some operating aspects of the fog-generating device. Access to these parameters occurs through the $READ and $WRITE sentences.

Table 4 shows an example of some of the variables which can be made available by the system; the contents of the columns is as follows:

Name is the identifier of the variable which must be included in the same field of the $READ and $WRITE messages. It is case sensitive and cannot contain spaces.
Type inclused information about access modes: "R" for read-only, "W" for write-only, "R/W" for read and write;
Static defines whether the variable will be stored in a non-volatile way in the control board of the fog-generating device upon receiving the related $WRITE message. For technologic reasons, the internal flash has a maximum possible number of erasing/writing cycles: to avoid an excessive wear of the internal memory and guarantee at the same time a reliable operation, the microcontroller on board the control board of the fog-generating device will allow a limited number of writings in flash, after having exceeded which, all variables marked as static will not be saved any more in a non volatile way and will therefore have to be restored upon every power-on.

The microcontroller of the fog-generating device will communicate the occurred intervention of the protection by activating the memlock flag.
• Value includes the representation mode of the variable in the message data field.
• Description shows in detail the meaning of the relevant variable.

Tabella 1 - System Variables

*Name*	*Type*	*Static*	*Value*	*Description*
shtype	R/W	Yes	'0' '1' '2'	Defines the type of shooting required between the time ('0'), pluses ('1'), with fog sensor ('2') modes. The actually accepted modes change depending on the machine type.
shtime	R/W	Yes	2 ASCII-HEX (8 bit) alphanumeric digits	Defines the shooting time expressed in [s] for the time mode and for the initial pulse of the pulses/fog sensor modes.
shmark	R/W	Yes	2 ASCII-HEX (8 bit) alphanumeric digits	Defines the shooting time expressed in [s] for the pulses following the first one in pulses/fog sensor modes.
arm	R/W	No	'0' or '1'	Defines the arming signal status, '0' for non-armed machine and '1' for armed machine. The actual arming status of the machine is determined by the logic AND operation between this variable and the local arming input on board the card.
				When reading, the real arming status is returned, not the previously remotely programmed value.
faileds hot	R/W	No	'0' or '1'	Returns the result of the last shooting event: '0' in case of shooting performed with success, '1' if an anomaly has not allowed correctly performing the shooting. When writing, only value '1' is accepted; it is not possible to set this flag to 0 from a remote command.
armblan k	R/W	Yes	2 ASCII-HEX (8 bit) alphanumeric digits	Defines the delay time expressed in [s] between setting of the arming command (logic AND between local and remote values) and the actual receipt in ordero to enable the shooting.
Tboil	R	N/A	4'ASCII-HEX (16 bit) alphanumeric digits	Returns the boiler temperature. Data are expressed in [°C].
empty	R	N/A	'0' or '1'	Returns '1' if at least one of the installed bottles is empty, '0' otherwise.
tamper	R	N/A	'0' or '1'	Returns '1' in case of intrusion under way, '0' otherwise.
ready	R	N/A	'0' or '1'	Returns '1' if the machine is ready to shoot upon receiving the related command, '0' if one or more conditions necessary for shooting are not satisfied.
memlock	R	N/A	'0' or '1'	'0' means that variables defined as static will be immediately stored in a non-volatile way; '1' means that the number of rewritings provided for a given model of fog-generating device is ended, therefore it is not possible to guarantee a writing in flash (data could anyway be stored in the following hours in a non-volatile way following the generation of an internal trigger for the backup of some data writings).
shspeed	R/W	Yes	'0' or '1'	Sets, in case of pump-type shooting mechanism, the normal ('0') or turbo ('1') mode.
fogshot	R	N/A	4 ASCII-HEX (16 bit) alphanumeric digits	Returns the cumulative fog emission time, expressed in [s], from the last application, online and off-line, of the TANKRESET command
cylstat	R	N/A	2 ASCII-HEX (8 bit) alphanumeric digits	Returns the detailed status of the bottles: every bit is '0' if the respective bottle is not empty, '1' if empty. Bit 0 is not significant, bit 1 refers to the first bottle being used, bit 2 to the second, bit 3 to the third (where present) and so on.

Claims

Method for transmitting a message between anti-theft devices of the fog-generating type through a serial channel, said message comprising an orderly sequence of characters, said sequence comprising a start-of-sequence marker character and an end-of-sequence marker character, said start-of-sequence marker being followed by at least one character which compose the data field of the message, said method comprising the steps of:
- sending the start-of-sequence marker character to an anti-theft device of the fog-generating type;

- sending the characters which compose the data fields of the message to the anti-theft device of the fog-generating type;

- remotely executing a control computation on the characters sent to the anti-theft device of the fog-generating type and sending the characters which represent the result of the control computation to the anti-theft device of the fog-generating type;

- comparing, by the anti-theft device of the fog-generating type, the characters which represent the result of the remotely performed control computation with the characters which represent the result of a control computation locally performed by the anti-theft device of the fog-generating type;

- sending the end-of-sequence marker character to the anti-theft device of the fog-generating type;

- interpreting and executing the message by the anti-theft device of the fog-generating type;

- issuing a reply by the anti-theft device of the fog-generating type;
wherein said message has the function of activating an arming of the anti-theft device of the fog-generating type and/or a shooting of the anti-theft device of the fog-generating type, said shooting activation message starting a shooting if the anti-theft device is armed, with enough filled-in bottles, at a temperature and no failures or errors have been detected.
Method for transmitting a message between anti-theft devices according to claim 1, characterized in that the actual arming status of the fog-generating device is determined by a logic AND operation between the message adapted to axtivate an arming of the device and a signal send by a local arming input present on the anti-theft device.
Method for transmitting a message between anti-theft devices according to any one of claims 1 to 2, characterized in that the actual shooting status of the fog-generating device is determined by a logic OR operation between the message adapted to activate an arming of the device and a signal sent by a local arming input present on the anti-theft device.
Method for transmitting a message between anti-theft devices according to any one of the previous claims, characterized in that the maximum length of the message, from the start-of-sequence marker character to the end-of-sequence marker character, is less than or equal to 32 characters.
Anti-theft device of the fog-generating type comprising means for transmitting a message through a serial channel, said message comprising an orderly sequence of characters transmitted by using the method according to any one of the previous claims.
Anti-theft device of the fog-generating type according to claim 5, characterized in that it comprises a control board, and in that the transmission of the message with the control board of the fog-generating device occurs through a serial channel with 3 wires (Tx, Rx, GND).
Anti-theft device of the fog-generating type according to claim 6, characterized in that the transmission of the message occurs between the control board of the fog-generating device and a remote board connected to the control board of the fog-generating device.
Anti-theft system of the fog-generating type comprising an anti-theft device of the fog-generating type according to claim 7, characterized in that the system comprises a second anti-theft device connected to the remote board.