JPS6016745A - Priority recognizing system in loop form network - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency by providing a trigger bit to a signal block to be transmitted to attain priority communication of many levels. CONSTITUTION:A frame synchronizing signal SYN and a trigger signal TRG at each prescribed period are transmitted from a clock station. Each data station has a counter, which is reset by the synchronizing signal SYN and incremented by 1 each with the trigger signal TRG. In the communication, a station having the priority of ''0'' makes communication while the counter is in ''0'' and a station having the priority ''1'' makes communication when the counter is in ''1'' similarly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scheme in which each node station is aware of its priority in a looped network providing prioritized communications.

As a loop type network that provides priority-based communication, there is a network described in Patent No. 93-58-54117. Such a network consists of multiple node stages 1, 2, 3, 4, as shown in FIG. 5.
6 and a clock station controller 8, these stations are connected by a loop-shaped transmission path 7.

In this conventional example, each node station is notified by adding information indicating the priority to the signal processor.

FIG. 2 shows the configuration of a signal block used in this conventional example. FIG. 2(a) shows signal blocks used for node-station communication, including preamble signal PR1 start flag SF1 synchronization signal FIY, priority information prtr, destination address DA, sender address S person, information INFO, and end flag EF. It is composed of. Figure 2 (b>
shows the structure of the synchronization signal and trigger signal transmitted by the clock station 8. Clock station 8 has a constant period To, bit 5Y = 1, P'fLI = 0
A periodic signal SYN of 00 is supplied to the loop as shown in FIG. This PRI=000 gives the highest priority level 0. When each node station detects the passage of this synchronization signal SYN, it resets its built-in timer to synchronize with the period To, reads the PRI, and indicates the priority level given by the PRI. As shown in FIG. 3, the signal block PKT having the configuration shown in FIG. 2(a) is sent out after the synchronization signal syN, or after the signal block PKT has already been sent out from the upstream node station. The clock station 8 removes the synchronization signal SYN that has made a round on the transmission line 7, and after obtaining the transmission right, the clock station 8 issues PRl.
, =001 is sent to the transmission line 7. This gives priority level 1, which is one level lower than priority level O. Thereafter, a lower priority level 2 is given to the trigger signal 'I' RG 2 of PRI=010 in the same manner. Although priority is given to the communication carried out on the transmission line 7 as described above, this conventional example has the following problems. That is, as the number of priority levels increases, the priority information P
Since the bit length of the RI becomes longer, the fixed portion of the signal block becomes longer, and the transmission efficiency decreases.

An object of the present invention is to provide prioritized communication with high transmission efficiency by shortening the fixed portion of a signal block.

According to the present invention, each node station has a counter circuit that counts the number of the trigger signals passing through the loop-shaped transmission path, and when receiving the synchronization signal, the counter circuit is reset and the output of the counter circuit is Recognize the priority of communications that can be sent. FIG. 4 shows the configuration of a signal block used in the eight-priority system according to the present invention.

FIG. 4(,) shows a signal block used for node-station communication, and FIG. 4(b) shows a synchronization signal and a trigger signal. Priority information for the constituent companies in Figure 4 and the composition in Figure 2 P R
, I is replaced by TG. In FIG. 4, bit 8Y=1 indicates that the signal is a synchronization signal, and bit TG-1 indicates that there is a trigger signal. In the signal block sent by the node station, 5Y=
-TO=0. Clock station 8 is
5A synchronization signal 8YN with Y=1 and TG=0 is sent out at a period To as shown in FIG. Send.

Thereafter, within the period To, the trigger signal TRG is repeatedly sent out every time the transmission right is acquired. Each node station is
B) When SY=1 is received, the built-in counter is cleared, and when bit TG=1 is detected, the counter is incremented by one.

The output of the counter at this time is shown in FIG. 5(b). This output corresponds to the priority level, and each node station performs transmission based on the output of the counter.

FIG. 6 shows the configuration of the node station in the present invention. The node station in FIG. 6 has an input terminal 10 connected to a transmission line 7. It has an output terminal 11, a signal detection circuit 12, a control circuit 13, a buffer 18, and a counter 1.
4, timer 15, transmission buffer 16. '4i1' is formed from the switch 17. The signal detection circuit 12 detects bit 5y=from the signal block received via the buffer 18.
When i is detected, the timer 15 and counter 14 are reset. Still, when bit TG=1 is detected, the counter 14 is incremented by one. The control circuit 13 recognizes the priority level from the output of the counter 14, and when a transmission with a priority level equal to or higher than this priority level occurs,
After acquiring the transmission right, the switch 17 is transferred to the transmission buffer 16.
Connect to the side and perform transmission. The signal block to be transmitted is
Bit 5Y=TO=O. Note that in the above explanation, the synchronization signal is 5Y=1, TO=0, but 8Y=T (j=1
You can also use it as In this case, when the control circuit 12 of each 7-station station detects 5Y=1, it clears the counter 14 and does not increment it.

As described above, according to the present invention, by providing trigger pits without adding priority information to the signal blocks to be transmitted, it is possible to capture and provide priority communications at many levels, and as a result, the transmission efficiency of communications can be improved. can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of the loop type network in the present invention, and FIG. 2 is the configuration of the Shinzuki block in the conventional example.
Figure 3 shows the 8IΦ production tie in the conventional example [ne], the 6th
The figure shows an embodiment of the present invention. In FIGS. 1 and 6, 1. 2. 3. 4.
5°6? '', node station, 7 is a transmission line, 8 is a clock station, 12 is a signal detection circuit, 13 is a control '++11 circuit, 14 is a counter, 15 is a timer, 16
17 indicates a switch. 71 Figure 2 Figure 3 0 1 2

Claims (1)

[Claims] In a loop type network in which a plurality of node stations and a clock station are connected by a loop-shaped transmission line, and the clock station supplies a synchronization signal at a constant cycle and further supplies a trigger signal within the cycle,
The node station has a counter circuit that counts the number of trigger signals passing through the loop-shaped transmission path, resets the counter circuit when receiving the periodic signal, and calculates the transmission iT from the output of the counter circuit.
A priority recognition method in a loop type network, which is characterized by recognizing the priority of communication.