CN106911334B - Fire-fighting industrial bus coding method - Google Patents

Abstract

The invention discloses a fire-fighting industrial bus coding method, which comprises the following steps: (1) the fire alarm controller takes a low level pulse with a duty ratio below 0.3 as a bit code division starting point to carry out coding and synchronizes signals; (2) during coding, a bit '0' is determined by the pulse width between two level falling edges, and a bit '1' is determined by the pulse width between two level rising edges; each two-end falling edge is endowed with an independent synchronous signal during coding; (3) and (3) repeating the step (2) for continuous coding until the coding is finished, and then sending the codes to the intelligent component through the bus. The invention has simple flow and simple and convenient coding mode, and can avoid the problem of longer idle time of the bus while ensuring the accuracy of data transmission, thereby being suitable for popularization and application.

Description

Fire-fighting industrial bus coding method

Technical Field

The invention relates to the technical field of fire fighting, in particular to a fire fighting industry bus coding method.

Background

In the conventional fire alarm control system, when a bus is used for transmitting a code, a controller host needs to be pulled high in a low level state, when the host transmits a string of data, such as '00101', the start bit of information transmission is the first bit of data, the time for transmitting each bit of data is fixed, and therefore the time for transmitting the string of data is also a fixed value. The encoding mode has the advantages that the phenomenon of clock advance or delay can occur in the information transmission process, so that during encoding, errors are generated during transmission of first-bit data, the whole data encoding process is promoted to form accumulated errors, encoding is incorrect finally, the accuracy of clocks at two ends of communication is reduced, the accuracy of data transmission is lowered, and the subsequent data verification can be greatly influenced.

For the above reasons, some manufacturers currently use manchester coding (e.g., the technique disclosed in patent No. 02129002.4) to divide the time into equally spaced segments, each of which represents a bit, in order to ensure the accuracy of the data during encoding and reduce the accumulated error caused by the clock. Each small time is divided into two halves, the signal transmitted in the first half is the code reversal of the bit value transmitted in the time interval, and the bit value itself is transmitted in the second half. Although the mode generates synchronous signals when the level changes, so that errors caused by delay or advance of a clock during coding are reduced, the idle time is longer in each level change period, so that the capacity of external part capacitors has higher requirements, and the hardware acquisition cost is higher; at the same time, the load capacity of the bus also deteriorates, resulting in a reduction in its power supply and driving capabilities to the back-end devices.

Disclosure of Invention

Aiming at the technical defects, the invention provides a fire-fighting industry bus coding method which can avoid the problem of long bus idle time while ensuring the accuracy of data transmission.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a fire-fighting industry bus coding method comprises the following steps:

(1) the fire alarm controller takes a low level pulse with a duty ratio below 0.3 as a bit code division starting point to carry out coding and synchronizes signals;

(2) during encoding, determining bit '0' or '1' according to pulse width between two level falling edges or rising edges, and simultaneously endowing two independent synchronous signals according to two ends of the bit of the two falling edges or rising edges;

(3) and (3) repeating the step (2) for continuous coding until the coding is finished, and then sending the codes to the intelligent component through the bus.

Further, in the step (2), the pulse width when the bit "1" is determined is twice the pulse width when the bit "0" is determined.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention takes a low level pulse width with extremely small duty ratio (below 0.3) as a bit code division starting point for coding, and has a synchronous signal, because the low level pulse width is far smaller than the high level, the idle time on a bus during coding is reduced, the power supply and the driving capability of external equipment can be ensured, the requirement on the capacity of external part capacitors is also reduced, and the cost of hardware purchase is reduced.

(2) The invention determines the bit '0' and '1' according to the pulse width between two level falling edges or rising edges, and simultaneously gives a synchronous signal which is independent of each other, so that compared with a Manchester coding mode, the invention not only has simple and convenient coding mode and simple flow, but also can ensure the accuracy of data transmission.

(3) The invention is buckled and closely connected with each other, and provides guarantee for high-efficiency coding and data transmission of the fire-fighting industrial bus, so that the invention is suitable for popularization and application in the fire-fighting technical field.

Drawings

FIG. 1 is a schematic flow chart of the present invention.

Fig. 2 is a schematic diagram of pulses.

Detailed Description

The present invention will be further described with reference to the following description and examples, which include but are not limited to the following examples.

As shown in fig. 1 and 2, the present invention provides a high-efficiency bus encoding method, which can ensure the accuracy of data transmission and avoid the load capacity deterioration caused by the long idle time of the bus. The main process of the invention is as follows:

first, a low-level pulse with a very small duty ratio (0.3 or less) is encoded as a bit division code start point, and a signal is synchronized. During encoding, a bit "0" is determined by the pulse width between two level falling edges (the pulse width is 400-500 μ s, including a low-level pulse width of 50-100 μ s), a bit "1" is determined by the pulse width between two level rising edges (the pulse width is twice the pulse width when the bit "0" is determined, and also includes a low-level pulse width), and the rising edges and the falling edges are schematically shown in fig. 2. In addition, in the embodiment, each two end falling edges are provided with an independent synchronous signal during encoding, so as to avoid the occurrence of accumulated errors in encoding caused by clock advance or delay.

In the above manner, the controller continues encoding until encoding is complete, and then transmits the code to the intelligent component via the bus.

According to the invention, through reasonable software and hardware combination, the accuracy of fire-fighting industrial bus data transmission is effectively improved, the power supply and driving capability of external equipment are ensured, and the hardware acquisition cost is reduced. Therefore, the invention well promotes the industrial bus coding technology to a new height, and has outstanding substantive features and remarkable progress compared with the prior art.

The above-mentioned embodiment is only one of the preferred embodiments of the present invention, and should not be used to limit the scope of the present invention, and all the technical problems solved by the present invention should be consistent with the present invention, if they are not substantially modified or retouched in the spirit and concept of the present invention.

Claims (2)

1. A fire-fighting industry bus coding method is characterized by comprising the following steps:

(1) the fire alarm controller takes a low level pulse with a duty ratio below 0.3 as a bit code division starting point to carry out coding and synchronizes signals;

(2) during encoding, determining bit '0' or '1' according to pulse width between two level falling edges or rising edges, and simultaneously endowing two independent synchronous signals according to two ends of the bit of the two falling edges or rising edges;

(3) and (3) repeating the step (2) for continuous coding until the coding is finished, and then sending the codes to the intelligent component through the bus.

2. A fire protection industry bus coding method as claimed in claim 1, wherein in the step (2), the pulse width when the bit "1" is determined is twice as wide as the pulse width when the bit "0" is determined.

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