DK142969B - PROCEDURE FOR CYCLIC PURPOSE IN A DATA TRANSFER - Google Patents

Description

in 142969

The invention relates to a method of cyclic invocation for substations which are called from a central station for data transfer. The central station and the substations can be connected to each other by means of a data transfer channel. As a transmission channel, semi-duplex or duplex-capable wire or radio chain connections are considered. The data is usually transferred from the substations to the central station. However, the invention also encompasses the reverse transfer direction.

To control the data traffic over one transmission channel, each substation receives an address. The central station invokes the data of the individual substations, cyclically transmitting the addresses of the stations, if necessary 15 together with a call command. If such a call has been issued, the called substation's response is awaited before the next call is issued.

Systems known to operate in such processes are known. It is a prerequisite for the operation that the central station is familiar with the addresses of all participating substations. Unknown stations are never called.

Thus, in German publication no.

2,100,777 discloses a device for automatic addressing and command delivery from a central station to several freely addressable substations, where from the central station prior to the start of the first call cycle, the individual stations are assigned individual addresses. However, after this address mapping, 30 from the central at the call cycle only the substations already included in the call cycle at the address mapping and which are known by the central station are taken into account. Thus, with the known device there is no possibility that individual substations 35 can step out of the cycle and, if necessary, return to the latter on their own initiative, just as with the known coupling it is not possible for substations which the central station had not so far had knowledge may occur in the 2 142969 cycle.

The object of the invention is to provide a method by which substations unknown to the central station can also enter the on-call cycle. In addition, the method according to the invention is characterized in that in the predetermined cycle, in addition to the special call (addressed call) to the central station known to each of the central station, the central station sends one or more special characters which are recognized by all stations and that stations which a predetermined number of cycles in succession has not received any special invocation, which then disposes of their data. After the sign, the Central Station holds a break that is at least as long as the break after a call.

Substations that are not registered in the central station and consequently are not called addressed during the call cycles, thus receive the distinctive sign, and if a substation during one cycle or for several cycles after each other has not been called under its address, this station must connection to the special broadcast its data. The central station can now include this substation in the call cycle, if necessary, depending on a special enrollment procedure.

25 In order to prevent multiple substations from registering at the same time in response to the distinctive character, it is appropriate to delay the commencement of the broadcast from the substation by means of a random generator, cf. German patent application P 22 49 670.4.

In the following, an embodiment of the data transfer system according to the invention will be explained in more detail with reference to the drawing, in which fig. 1 shows a data transfer system with two central stations and a plurality of substations; and FIG. 2 sexually different call cycles and storage contents respectively at a central station depending on a changing number of substations within its operating area.

For example, the two central stations 1 and 2 may be rank centers for a large railway station or for two neighboring railway stations.

3 142969

In addition to a calculator 3,4, each central station contains a storage 5, 6 and a transmit / receive part 7,8. The transmitting / receiving parts of both central stations are tuned to the same frequency f. The transmitter's range 5 is dimensioned so that the transmission areas do not overlap.

At substations 9-13 one must imagine railroad officials equipped with portable and tuned frequency and selective call-10 receivers. The stations 9 and 10 of the transmission area of the central station 1 have selective call characters A and D, and the stations 11-13 of the central station 21's transmit area respond to the selective call characters B, E and C.

15 The bearings 5 and 6 respectively are made up of under bearings. In FIG. 1, this is indicated by the dotted lines.

For example, if the central station 1 is brought into operation, the calculator 3 causes a special character to be transmitted over the transmit / receive part 7. The special character corresponds to the collective-subsidiary group call character for all stations 9-13. For example, if the substation 9 <is switched on, it will, in response to this particular character, transmit its selective call character A. The selective call sign is received by the central station 1 over the transmitting and receiving portion 7, after which the calculator 3 addresses one of the sub-stores in the storage 5 with the character A and the neighboring station. bearing with the special character S, see fig. 2a. The substrate A is thus firmly attached to the substation 9.

30 Now the addressed subplots are cyclically scanned by the calculator. When scanning the sub-layer A, the transmitting and receiving part of the central station sends a binary coded data block composed of the special call character A as the address and a command model. For example, the command portion consists of a coded instruction for the named substation to transfer the numbers of all wagons on a particular ranking track to the central station. After such a data block has been broadcast, the central station first awaits the called substation's response.

The data transmitted from the substation 9 is supplied by the control apparatus A.

The calculator then scans the next addressed sub-layer, the sub-layer S, see fig. 2a. This sends the sending / receiving part distinctive. In this way, all substations in the transmitting area of this central station are activated, which the calculator has not yet assigned any sub-storage, and which thus far have been unknown to the central station.

If no unknown substation appears, the invocation cycle begins again with the invocation of the substrate A. However, if the substation 10 has been switched on in the meantime, it sends its selective call sign 15D upon receipt of the special sign. The calculator then addresses the sub-layer which had hitherto had the address S, with the selective call sign D and the next sub-layer with the special sign S, see fig. 2b. In this way, the substation 10 has thus been accommodated in the cycle by means of the special character. It can now receive instructions from the central station and, for its part, transmit data to the central station.

If one of the substations 11-13, e.g. the substation 13 with the selective call sign C, switches, for example, when ranking carts from the transmitting area of the central station 2 to the transmitting area of the central station 1, it can, after receiving the special sign, send its selective call sign, and it is then recorded in a similar manner as just depicted in the call cycle as well, see fig. . 2c.

30 If one of the substations recorded in the cycle for a predetermined number of consecutive cycles does not respond to the central station's call, be it because it has left that central station's transmitting area because it has fallen out as a result of a fault, or simply because there is no more data to transmit, the calculator causes this substation to be taken out of the cycle, deleting the address and contents of the associated sub-

Claims (3)

142969 tes. For example, if the substation 13 does not return to the transmitting area of the central station 2 within the predetermined period, it falls out of this central 5's call cycle BCES and the new cycle only includes the addresses BES (see Fig. 2d). The advantage of the system according to the invention is that a further information path between the central stations can be waived. A substation that will switch to another central station area does not have to sign up at its central station. The withdrawal from this station's call cycle occurs automatically, and the registration at the new central station makes the substation itself. In the known facilities, this substation 15 had to first report at its central station so that it could report it at the other central station and occupy a storage space for it. Thereby errors can easily occur. PATE N'T REQUIREMENT 20 1 · Procedure for cyclic invocation for sub stations which are called from a central station for data transfer, characterized in that the central station in the predetermined cycle in addition to the special invocation (addressed invocation) for each 25 of the central station known substations transmit one or more distinctive characters recognized by all substations and that substations which, during a predetermined number of cycles in succession, have not received any special invocation, which then allocate their data. Method according to claim 1, characterized in that the central station occupies a substation in the call cycle if this substation was hitherto unknown and has registered in response to the sign. 3. A method according to claim 1 or 2, characterized in that the timing of a substation's sending start in response to a particular character is made dependent on a random generator.