CN2854948Y

CN2854948Y - Intelligent industial bus transceiver

Info

Publication number: CN2854948Y
Application number: CNU2005200441227U
Authority: CN
Inventors: 闵庆浩; 张志来; 顾牧君
Original assignee: SHANGHAI MINDA NETWORK TECHNOLOGY Co Ltd
Current assignee: SHANGHAI MINDA NETWORK TECHNOLOGY Co Ltd
Priority date: 2005-08-05
Filing date: 2005-08-05
Publication date: 2007-01-03
Anticipated expiration: 2015-08-05

Abstract

The utility model relates to an intelligent bus transceiver for industry, which comprises a transmit-receive processing module for receiving and transmitting data; and a transmission and collision detection module for determine transmitting or delay-waiting by detecting current variation in the whole bus circuit. When detecting there is no transmission from other terminals, transmitting immediately; otherwise, waiting based on the different primary delay-waiting time of each terminal. The transceiver provided in the utility model adds collision detection so as to realize avoidance when there is collision, thus the signal transmission can be active and to a certain extent real time.

Description

Intelligent industrial bus transceiver

Technical field

The utility model relates to a kind of Network Transmission bus, relates in particular to a kind of data collector of industrial transfer bus.

Background technology

At present many transfer bus of big family expenses are based on the transfer bus of RS-485 in the intelligent residential district.RS-485 is the serial data interface standard in fact just, and it is development on the basis of the RS-232 that is worked out and issued by Electronic Industries Association (EIA) at first.EIA has formulated the RS-485 standard in 1983 again, increase multiple spot, two-way communications capabilities, promptly allowed a plurality of transmitters to be connected on same the bus, increased the driving force of transmitter simultaneously, expanded the bus common mode range, back called after TIA/EIA-485-A standard.Because the recommended standard that EIA proposes all is as prefix, so everybody custom is made the prefix appellation with above-mentioned standard with RS with " RS ".

The electrical characteristic of a RS-485 standard docking port is made regulation, and do not relate to connector, cable or agreement, the user can set up the high-level communications protocol of oneself on this basis.As seen from Figure 1: since be subjected to can only to have the same transmission medium of being limited in of the own standard of RS-485 (transmission line) on one be in send data state all the other can only be in the reception data mode, so the state that system just must have a leader (calling main frame in the following text) to coordinate each terminal under by the situation of a plurality of terminal coexistences guarantees that transmission medium does not make a mistake.Terminal more just needs main frame to come dispatch terminal adjustment state to send data successively in system, and just terminal will send if any data needs the allowance of wait main frame just can send.General processing method is: each terminal is carried out queuing successively, that is to say, no matter whether this terminal has data to send, all carry out from top to bottom; Perhaps in other words, if 20 terminals are arranged, even the nineteen of front all will not send, the 20 also will be waited the detection of front intact, just can take turns to; To produce the delay that data send and the time of this delay thus can strengthen with the increase of terminal quantity, just the non-instantaneity of transfer of data;

Summary of the invention

The utility model technical issues that need to address have provided a kind of intelligent industrial bus transceiver, are intended to solve above-mentioned defective.

In order to solve the problems of the technologies described above, the utility model is achieved through the following technical solutions:

The utility model comprises a transmitting-receiving processing module in order to data are received or send; Comprise that also one can change transmission and the collision detection module that decides transmission or postpone to wait for by the electric current that detects on the whole bus loop; Described transmission and collision detection module link to each other with the transmitting-receiving processing module, and with the transfer bus Data Receiving and driver module is two-way is connected.

Compared with prior art, the beneficial effects of the utility model are: thus because transceiver has increased collision detection has realized that dodging when conflict makes and can initiatively send signal, accomplished the real-time of signal transmission so to a certain extent.

Description of drawings

Fig. 1 is the link block figure of each terminal of industrial bus;

Fig. 2 is a module map of the present utility model;

Fig. 3 is a schematic diagram of the present utility model;

Fig. 4 is a flow chart of the present utility model;

Embodiment

Below in conjunction with accompanying drawing and embodiment the utility model is described in further detail:

As seen from Figure 2: the utility model comprises a transmitting-receiving processing module in order to data are received or send; Comprise that also one can change transmission and the collision detection module that decides transmission or postpone to wait for by the electric current that detects on the whole bus loop; Described transmission and collision detection module link to each other with the transmitting-receiving processing module, and with the transfer bus Data Receiving and driver module is two-way is connected;

When detecting other terminal when not sending, both carved transmission; When detecting other terminal when transmission is arranged, postpone the stand-by period according at the beginning difference and wait for each terminal.

As seen from Figure 3: the basic principle of collision detection of the present utility model is to utilize data-signal electric current in the transmission driver when sending to change to realize:

If establish driving voltage is V ₀Load resistance is R _ZWhen having only transceiver loop current when sending signal in the loop is V ₀/ R _Z, be normal condition this moment; When sending signal simultaneously, two transceivers, flow through the electric current or the V of load resistance like this because the output voltage of each driver is identical ₀/ R _ZThen the actual output current of each driver is V ₀/ R _ZHalf.The variation of these electric currents can be passed through sample resistance R ₀On change in voltage reflect, this voltage will be exported different level signals by voltage comparator, just can detect the transmission signals from collision.How the utility model dodges conflict if also having solved: it constantly knows all whether signal is arranged on the transmission line all to be in accepting state when each transceiver is online, if the agreement transceiver needs a stand-by period and claims that this time is the silence period before will sending signal, (silence period is meant that transceiver is obtained needs minimum transfer line free time of observing before the transmission route.The transmission priority that in fact the adjustment silence period can regulate each node on the transmission line.) when sending, signal produced conflict, and at this moment will to return and be ready for sending the delay time that conflict here makes a concession again be at random to transceiver, as shown in Figure 4.Just priority can have been set like this if different signal contents can also be given different delay times by agreement.The active that can finish signal by the cooperation transceiver of software and hardware sends.

Claims

1. an intelligent industrial bus transceiver comprises a transmitting-receiving processing module in order to data are received or send; It is characterized in that: comprise that also one can change transmission and the collision detection module that decides transmission or postpone to wait for by the electric current that detects on the whole bus loop; Described transmission and collision detection module link to each other with the transmitting-receiving processing module, and with the transfer bus Data Receiving and driver module is two-way is connected.