cigarettes come out of a cigarette production machine 10 and are conveyed in the form of an unordered stream of cigarettes 11 containing , for example , of the order of 1 , 000 cigarettes per meter of transport section in the direction of the arrow by means of a transport section 12 to a packing machine 13 . the transport section 12 comprises a plurality of transport devices 14 - 17 which are drawn in the figures purely schematically as conveyor belts but by no means are restricted to these . the transport section 12 comprises inter alia a fifo cigarette store 16 having a transport device 18 whose length is variable depending on storage demand as indicated in fig1 by means of dotted lines . in the cigarette production machine 10 product data about the cigarettes produced are present , for example cigarette quality data , brand information , an identification of the production machine 10 , date and time of production , etc . the product data tracking system comprises a data processing unit 20 having a control means 21 and a storage means 22 . the control means 21 requests production data from the cigarette production machine 10 and periodically writes corresponding production data sets 30 a , 30 b , 30 c , . . . into the storage means 22 . by this means the product mass flow 11 is virtually subdivided into product portions 11 a , 11 b , 11 c , . . . as indicated in fig1 by dotted lines . when the transport speed of the stream of cigarettes 11 through the transport section 12 is , by way of example , 20 cm / s and the control means 21 writes production data requested from the cigarette production machine 10 once a second as production data sets 30 a , 30 b , 30 c , . . . into the storage means 22 this corresponds to a virtual apportioning of the product mass flow 12 into product portions 11 a , 11 b , 11 c , . . . of a certain length , in this example a portion length of 20 cm . in doing this , the production data set usefully contains production data averaged over one storage period . an example of a format for a production data set 30 is shown in fig2 . a production data set 30 comprises by way of example a field 31 for storing the cigarette brand , a field 32 for storing the identity of the cigarette production machine 10 , a field 33 for storing the production date and time , a field 34 for storing the portion length ( in cm in this case ) and fields 35 , 36 , . . . for storing cigarette quality data such as the average weight , the standard deviation of the average weight , etc . the label “ 1 ” in the product occupancy identification field 40 indicates that the data set 30 corresponds to a product portion and is not , for example , an empty portion as a result of an interruption of the product mass flow 11 . preferably , production data sets are written into the storage means 22 only when the product enters the transport section 12 . for this purpose , the entry sensor 23 is provided , which sends a corresponding signal to the control means 21 when a product enters the transport section 12 in order to activate the write operation , or in the event of an interruption of the product mass flow entering the transport section 12 to interrupt the write operation by means of a corresponding signal . in a preferred embodiment the storage means 22 comprises at least one fifo stack memory 26 in which the product data sets 30 a , 30 b , 30 c , . . . are stored in predetermined sequence in the form of a stack , wherein the product data sets 30 a , 30 b , 30 c . . . first filed on the stack are read out again in the same sequence 30 a , 30 b , 30 c , . . . by taking them out of the stack ( fifo principle ). at the exit end of the transport section 12 an exit sensor 24 is preferably provided in order to detect product emerging from the transport section 12 . in the event of product emerging from the transport section 12 the control means 21 can , if required , read out the associated product data set from the storage means 22 and make it available for further use , for example transmit it to the packing machine 13 . this occurs when using a fifo stack memory simply by periodic taking off of a product data set from the stack . due to the fixed sequence within the stack and the fifo principle it is ensured that the product data sets 30 a , 30 b , 30 c , . . . are correctly assigned to the product portions 11 a , 11 b , 11 c , 11 d . . . emerging from the transport section 12 regardless of the length of the transport section 12 in question , in the cigarette store 16 for example . the read - out period is usefully adapted to the exit period of the emerging product portions 11 a , 11 b , 11 c , 11 d , . . . which is associated with the length of the emerging product portions 11 a , 11 b , 11 c , 11 d , . . . . when the emerging product portions 11 a , 11 b , 11 c , 11 d , . . . are of constant length and the transport speed over the entire transport section 12 does not change , the read - out period usefully matches the storage period . it is not absolutely essential to provide a separate entry sensor 23 . the information about product entering the transport section can also be obtained , for example , from a component preceding the transport section 12 , in this case from the cigarette production machine 10 , if the information identifying a product portion is available there . the same applies to the exit sensor 24 , which can be dispensed with when the information identifying a product portion can be obtained , for example , from a component downstream of the transport section , the packing machine 13 in this case . this can be the case , for example , when instead of the length of the product portions in the transport direction the number of individual products per portion is used to define a product portion . even in the event of a stoppage of the product mass flow entering the transport section 12 it is not excluded to write product data sets to the storage means 22 . these then usefully contain a corresponding label , “ 0 ” for example , in a product occupancy identification field 40 in the product data set 30 ( see fig2 ). fig3 a to 3 c serve to explain the storage and reading operation for a ring memory and a fifo stack memory . in fig3 a the passage of a mass flow of cigarettes through the transport section 12 is shown schematically , wherein successive points in time are shown from top to bottom . the vertical line “ e ” designates entry into and the vertical line “ a ” exit from the transport section 12 . a product portion arranged over the line “ e ” is detected by the entry sensor 23 and a product portion arranged over the line “ a ” is detected by the exit sensor 24 . in fig3 b the corresponding memory state in each case of a ring memory 25 in the storage means 22 for storing the product data sets 30 a , 30 b , 30 c , . . . is illustrated . in fig3 c the corresponding memory state in each case of a fifo stack memory 26 in the storage means 22 for storing the product data sets 30 a , 30 b , 30 c , . . . is alternatively shown . the memory units 25 a , 25 b , 25 c , . . . of the ring memory 25 or the memory units 26 a , 26 b , 26 c , . . . of the fifo stack memory 26 serve for storing a product data set 30 . the ring memory 25 comprises a write pointer 27 and a read pointer 28 . the fifo stack memory 26 comprises a stack input 50 and a stack output 51 . the embodiment shown in fig3 b with a ring memory will be described first of all . at time t 1 , for example at start - up of the transport section 12 , the product mass flow 11 has not yet entered the transport section 12 . the write pointer 27 and the read pointer 28 are set to the same memory unit 25 a of the ring memory 25 . at time t 2 product running into the transport section 12 is detected by the entry sensor 23 , a corresponding data set “ 1 ” is produced by the control means 21 and written to the memory unit 25 a identified by the write pointer 27 . after this , the write pointer 27 is shifted by one memory unit while the read pointer 28 is kept in position since no product leaving the transport section 12 has been found . at time t 3 product running into the transport section 12 is detected by the entry sensor 23 , a corresponding data set “ 2 ” is generated by the control means 21 and written to the memory unit 25 b identified by the write pointer 27 . after this , the write pointer 27 is again shifted by one memory unit . in analogous fashion at time t 4 the product data set corresponding to the product portion “ 3 ” is written to the memory unit 25 c identified by the write pointer 27 and the write pointer 27 is again shifted by one memory unit . at time t 5 the entry sensor 23 detects that the product mass flow 11 entering the transport section 12 has been interrupted and therefore stops writing product data sets to the ring memory 25 . at time t 6 the exit sensor 24 detects that product is leaving the transport section 12 . accordingly , it reads the product data set “ 1 ” to which the read pointer 28 refers from the ring memory 25 and which corresponds to the exiting product portion “ 1 ”. after this , the read pointer 28 is shifted by one memory unit . at time t 7 the product data set “ 4 ” is written to the memory unit 25 d identified by the write pointer 27 and the write pointer 27 is shifted by one memory unit and also the product data set “ 2 ” is read out of the memory unit 25 b identified by the read pointer 28 and the read pointer 28 is shifted by one memory unit . at time t 8 the product data set “ 3 ” is read out of the memory unit 25 c identified by the read pointer 28 and the read pointer 28 is shifted by one memory unit . at time t 9 the exit sensor 24 detects that the product mass flow coming out of the transport section 12 has been interrupted and accordingly stops reading product data sets out of the ring memory 25 . at time t 10 the exit sensor 24 detects that product is coming out of the transport section 12 . accordingly , the product data set “ 4 ” is read out of the memory unit 25 d identified by the read pointer 28 and the read pointer 28 is shifted by one memory unit . at time t 11 the transport section 12 is empty and the ring memory 25 is in a state as at time t 1 . since in this embodiment the write and read pointers 27 , 28 are shifted along the memory units the memory is constructed as a ring memory 25 so that after a certain end memory unit the write and read pointers 27 , 28 are shifted to a start memory unit ( see time t 11 ). in an embodiment having a fifo stack memory 26 as shown in fig3 c the stack memory 26 at time t 1 is empty . the stack memory 26 has a stack input 50 and a stack output 51 . at time t 2 product running into the transport section 12 is detected by the entry sensor 23 , a corresponding data set “ 1 ” is generated by the control means 21 and placed on the stack , i . e . written by the stack input 50 to the stack memory 26 . at time t 3 product running into the transport section 12 is detected by the entry sensor 23 , a corresponding product data set “ 2 ” is generated by the control means 21 and written to the stack memory 26 . in analogous manner at time t 4 the product data set “ 3 ” corresponding to the product portion “ 3 ” is written to the stack memory 26 . at time t 5 the entry sensor 23 detects that the product mass flow 11 entering the transport section 12 has been interrupted and accordingly stops writing product data sets to the stack memory 26 . at time t 6 the exit sensor 24 detects that product is leaving the transport section 12 . accordingly , it takes the product data set “ 1 ” from the stack , i . e . it reads out the product data set “ 1 ” from the stack output 51 of the stack memory 26 . at time t 7 the product data set “ 4 ” is written to the stack memory 26 and the product data set “ 2 ” is read out of the stack memory 26 . at time t 8 the product data set the product data set “ 3 ” is read out of the stack memory 26 . at time t 9 the exit sensor 24 detects that the product mass flow 11 coming out of the transport section 12 has been interrupted and accordingly stops reading product data sets out of the stack memory 26 . at time t 10 the exit sensor 24 detects that product is coming out of the transport section 12 . accordingly , the product data set “ 4 ” is read out of the stack memory 26 . at time t 11 the transport section 12 is empty and , therefore , so is the stack memory 26 . to each transport apparatus 14 - 17 in the transport section 12 a respective data subset memory can be assigned , in particular a ring memory 25 each with write and read pointers 27 , 28 or a fifo ( or possibly a filo ) stack memory 26 . this allows handover of product data sets from one subset memory to a following subset memory on transfer of the corresponding product portions from one transport apparatus to the next transport apparatus . in particular on handover the product data sets can usefully be altered . this can be advantageous in particular when different conveying speeds occur in the transport section 12 . in the example in fig1 it may be assumed that the conveyor 14 moves at 20 cm / s while the conveyor 15 moves at 25 cm / s and the product portions on entering the transport section 12 have a length l of 20 cm . after the transition of the product portions from the conveyor 14 onto the conveyor 15 they become longer and flatter due to the increase in speed ; more precisely they have a length of 25 cm determined by the ratio of the transport speeds . if now , for example by means of a handover sensor between the conveyors 14 and 15 , it is detected that a certain product portion is coming out of the conveyor 14 the corresponding product data set is read out of the subset memory of the memory means 22 corresponding to the conveyor 14 , the length information in field 34 of the product data set is altered in accordance with the ratio of the transport speeds and the amended product data set is written to the subset memory of the following conveyor 15 . it is not absolutely essential , however , in the case of a plurality of transport apparatuses 14 - 17 or when different transport speeds occur in the transport section 12 that to every transport apparatus or every transport segment a respective data subset memory is assigned . this can be dispensed with when , instead of the length of product portions , a variable which is independent of the transport speed is used for determining the product portions , for example the number of individual products per product portion . a single data memory for the entire transport storage section can then be sufficient . the invention has been described in detail with respect to exemplary embodiments , and it will now be apparent from the foregoing to those skilled in the art , that changes and modifications may be made without departing from the invention in its broader aspects , and the invention , therefore , as defined in the appended claims , is intended to cover all such changes and modifications that fall within the true spirit of the invention .
the application relates to a method for tracking product data for a product mass flow in a transport storage section of the tobacco - processing industry having the steps : production of product data sets which each correspond to approximately equal portions of the product mass flow entering the transport storage section , writing the product data sets into corresponding memory units of a data memory and reading the product data sets corresponding to the product mass flow emerging from the transport storage section from the data memory . the application further relates to a corresponding product dating tracking system .