JPH0693686B2 - Address automatic setting method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a self-address automatic setting method in a multi-drop type communication control system using a common line.

2. Description of the Related Art Conventionally, there have been a manual type and an automatic type as an address setting method in such a communication control system. In the case of the manual type, as shown in FIG. 4, it is manually set by hardware, for example, by the address setting unit 41 by a dip switch, and when the power is turned on or when necessary, the communication control device 42 is used.
Is a method of reading the state of the address setting unit 41.
In this method, the setting itself is relatively simple, but it is necessary to know the addresses of all communication control devices in the same communication system in advance. In addition, there is a problem such as duplicate setting of the same address due to erroneous operation, and it is necessary to be careful when installing the system or adding a communication control device.

Next, a conventional automatic setting method will be described. In FIG. 5, assuming that the communication control device which is about to set its own address is the communication control device 51, the communication control device 51 uses a value that it can take, for example, "A", as its temporary address and an appropriate configuration. In a packet of (a packet having a data structure used at the time of setting a predetermined self address), that value is transmitted as the partner address onto the transmission medium. In this case, the self address is the same as the previous value, that is, the self address and the partner address are the same in the packet. The remaining communication control devices 52 to 5n connected on the same transmission medium receive the packet having such a configuration. If an "A" having the same address as the communication control device 51 exists in the communication control devices 52-5n, one of the communication control devices 52-5n returns a positive response. Communication control device
Upon receiving this acknowledgment, 51 recognizes that a communication control device having the same address already exists, and then repeats the same procedure for the address "B" different from the previous time. The communication control device 51 repeats the above-described procedure until there is a negative response (no response). When there is a negative response for the first time, the address value used at that time does not exist in the communication control system, and the value at this time is used as the self-address. This method is quite effective when the address range that can be taken is narrow, but when the address range is wide, the same procedure is repeated too often, and there is a drawback that it takes time to set.

Problems to be Solved by the Invention As described in the conventional example, a lot of time is required because the same procedure is repeatedly executed for self-address setting.

Means for Solving the Problems In order to solve the above-mentioned problems, in the self-address setting method of the present invention, the communication control device which attempts to set the self-address is connected to the same transmission medium by the simultaneous broadcast command. Requesting a response signal to all the other communication control devices, and when the other communication control device receives the broadcast command, the other communication control device returns a response signal in a predetermined packet format while performing contention control. The communication control device that intends to set the self-address determines the self-address based on the partner address contained in the first remaining unanswered response signal from the other communication control device.

Action The self-address can be set in a single procedure by the simultaneous broadcast command and the principle of contention control.

Example A self-address setting method according to the present invention in which a rule of contention control has a smaller address value and wins will be described with reference to the drawings. FIG. 1 shows an example of a broadcast packet. At the head of the packet, has a packet identification unit 11 that this packet is broadcast,
It is composed of a self address section 12, a partner address section 13 and a data section 14. At this time, the self address part takes the maximum value of the predetermined address system and the partner address part 13
Is an appropriate dummy value. The data section 14 includes information indicating that the packet is a self-address setting packet. FIG. 2 shows an example of a response signal packet for a broadcast packet. The packet identification section 21 is provided at the head of the packet, as in the broadcast packet, but the response signal packets are all the same. The self-address section 22 has addresses n, n + 1.
..., the address of the communication control device that transmitted the broadcast packet is stored in the partner address part 23, and the data part 24 is stored in the data part 24.
It contains information that this packet is a response signal packet to the broadcast packet for self address setting. Next, the self-address setting procedure will be described.

In FIG. 3, the communication control device 31 which attempts to set its own address sends the broadcast packet shown in FIG. 1 onto the transmission medium 30. When the communication control devices 3m, 3m + 1 ..., Which are connected to the transmission medium 30 and have n, n + 1 ... Attempts to return a response signal in the indicated packet format. If the contention control rule is such that a small address value wins, the transmission of the address value on the transmission medium is
Performed from B, "0" is stronger than "1". When contention occurs on the transmission medium, the communication control device that has sent "1" stops the subsequent sending of the address value. Therefore, the communication control device having the smallest address will win. Therefore, in this case, the communication control device m having the address value n will win. At the end,
The communication control device 1 receives the response signal packet from the communication control device m and knows that its address is n. According to the rule of contention control, since the addresses of the communication control devices connected to the transmission medium are all values larger than n, the communication control device 31 uses (n-1) as its own address.
If you use, you can set only one address value. Of course, the same consideration can be applied to the case where an address value having a larger contention control rule is more likely to win. In this case, the self address value is set to (n + 1) so that the address becomes a unique address. Further, the method of identifying the broadcast packet can be provided by providing an identifier to the packet as in this example, or the broadcast packet can be defined with a special partner address.

EFFECTS OF THE INVENTION As described above, if the self-address setting method according to the present invention is used, the self-address can be set in a single procedure, and the communication control device can be easily added to the system.

[Brief description of drawings]

FIG. 1 is a format diagram showing an example of a broadcast command packet in the self-address automatic setting method of the present invention,
2 is a format diagram showing an example of a response signal packet for a broadcast command packet, FIG. 3 is a system configuration diagram for explaining the automatic address setting procedure, and FIG. 4 is a self address manual setting method in the conventional example. FIG. 5 is a block diagram for explaining, and FIG. 5 is a system configuration diagram for explaining a self-address automatic setting method in a conventional example. 11,21 …… Packet identification part, 12,22 …… Self address part,
13,23 …… Partner address part, 14,24 …… Data part, 31,3m,
3m + 1 …… Communication control device.

Claims (2)

[Claims] 1. A multi-drop type network in which a plurality of communication control devices share the same transmission medium, and CSMA / C
In a communication control system using a communication protocol according to the D method, the communication control device, a communication control unit for controlling transmission and reception with another communication control device, a communication setting unit for selecting a communication rule of the communication control system, communication An address processing setting unit for calculating the self address from the information set in the rule setting unit, the address of the other communication control device from the communication control unit, and an address storage unit for storing the calculation result. A specific communication control device requests a response signal to all other communication control devices connected to the same transmission medium by a broadcast command, and the other communication control device When receiving the broadcast command, the
The response signal is returned while performing contention control, and the specific communication control device performs address processing on the other party address information contained in the first remaining response signal from the other communication control device via the communication control unit. The setting section calculates
A self-address setting method characterized in that a self-address is determined based on the partner address information and information selected by the communication rule setting unit, and the information is stored in an address storage unit. 2. A specific communication control device, as a rule of the contention control method, if a larger address value wins, +
1 if the smaller address value survives, -1
Is a self-address setting method in which the address obtained by adding or subtracting to the other party address included in the first remaining unanswered response signal from the other communication control device is used as the self-address.