RU2250566C2 - Electric signal transmission method - Google Patents

Abstract

FIELD: wire communication systems.

SUBSTANCE: proposed method for transferring electric signals from transmitter to receiver disposed in communication line incorporating voltage or current supply includes use of transmitter to transfer logical signal with aid of transmitter by varying inherent resistance in communication line and of receiver to read out current or voltage, respectively; signal is transmitted by two-bit number in ternary code with one of three probable resistances of communication line being set for each polarity of voltage or current supply.

EFFECT: enhanced self-descriptiveness, reduced cost.

2 cl, 2 ex

Description

The invention relates to wired communication systems, in particular to methods for transmitting information, namely, the transmission of information along the loops of alarm systems.

A known method of transmitting electrical signals in binary code from a transmitter to a receiver, interconnected by a two-wire communication line, comprising transmitting a logical unit and a logical zero from the transmitter by changing the voltage on the line and reading the voltage value in the line by the receiver (Technical description. UNIT 437241.002 TO "Device reception and control security and firefighter "Unitronic 426, 2002, www.unitest.ru).

The method provides a digital exchange of information between a transmitter and a receiver and is capable of transmitting large amounts of information in a short time. The disadvantage of this method is the relatively low noise immunity inherent in a digital communication system, and the high cost, especially the cost of peripheral devices - alarm system detectors, each of which must have a digital information processing device.

The closest in technical essence and the achieved result to the claimed method is a method of transmitting electrical signals from a transmitter to a receiver located on a communication line with a voltage or current source, including transmitting a logical signal by a transmitter by changing its resistance in a line and reading by the receiver, respectively, of the current value or voltage (Device "Signal-20P", operation manual АЦДР.425533.001 РЭ, 2001).

The method allows for analog-type communication between the control panel and detectors via signal loops, which leads to higher noise immunity.

The disadvantage of this method is its low information content, which requires tuning and programming devices to work with each type of detector.

In the framework of this application, the task of increasing the information content in the transmission of electrical signals in a communication line while maintaining the low cost of the transmission process is solved.

The problem is solved in that in a method for transmitting electrical signals from a transmitter to a receiver located on a communication line with a voltage or current source, including transmitting a logical signal by a transmitter by changing its resistance in a line and reading by the receiver, respectively, the current or voltage value, signal transmission carry out a two-digit number in the ternary code by setting one of the three possible values of the resistance of the communication line for each polarity of the voltage source.

In this case, the signal is transmitted by several parcels of two-digit numbers in the ternary code.

The essence of this method of transmitting electrical signals is to encode the transmitted signal with the simultaneous use of parameters inherent in digital and analog methods of transmitting information.

The method allows to increase the information content by increasing the number of signal combinations transmitted over the loop. If in a traditional loop it is possible to transmit only 4 signals (normal, alarm, circuit, open - and even for such information content, it is necessary to distinguish not three, but four signal levels, which reduces the reliability of communication), then in the present invention the number of distinguishable signals for stationary installation of the transmitter equal to 9, and when using the simplest pulse mode (the transmission of two packages of two-digit ternary numbers alternately) will be 46. Such information content in most cases is enough to transmit information in the loop of the system by the alarm.

Example 1

To implement this method of transmitting signals to a receiver with a voltage source (control panel), a signal loop with a terminal resistor is connected. The transmitter (in this example, is a signal loop with a fire or security detector installed on it) sets for each of the two polarities of the test voltage one of the three resistance values corresponding to a short circuit, an open in this polarity, or an average resistance value (corresponds to the resistance of the terminal resistor). With the help of the receiver, the current in the loop is measured and the type of event is determined from the resistance value - out of nine possible events, which is more informative compared to the analog loop, which provides information on four types of events (normal, alarm, open and short circuit).

Example 2

A signal loop with a terminal resistor is connected to a receiver with a voltage source (control panel). In each package, the transmitter sets for each polarity of the test voltage one of three resistance values corresponding to a short circuit, an open in this polarity, or an average resistance value (corresponds to the resistance of the terminal resistor). Using the receiver, the current in the loop is measured in both polarities alternately in each of the packages and the type of event is determined from the resistance value - out of 46 possible.

The advantages of the invention are ensured by the fact that this method of transmitting electrical signals, having much greater information content, is well compatible with the traditional method (some of the transmitted signals can be the same, the method only extends the number of transmitted signals), and therefore will allow the use of existing fire and security detectors, achieving greater informational content of loops. This, in turn, will simplify and reduce the cost of commissioning: refuse from setting up and programming alarm loops, use several types of detectors in one loop at the same time when detectors are automatically detected in the loop. This will reduce the required number of loops, which means it will save on the cost of cables and installation work.

In addition, the method allows you to organize the exchange of information between control panels, using its own signaling loops. To do this, the device is equipped with an additional device, which is connected to the signal loop of another device. The device imitates the operation of the alarm loop and, at the command of its device, sets one of three values of the output resistance for each polarity of the test voltage, thereby transmitting information to the second control panel. To increase the information content to 46, the loop simulator periodically changes the values of the output resistance.

Claims (2)

1. A method of transmitting electrical signals from a transmitter to a receiver located on a communication line with a voltage or current source, comprising transmitting a logical signal by the transmitter by changing its resistance in the communication line and reading the value of the current or voltage, respectively, characterized in that the logical signal is transmitted a two-digit number in the ternary code by setting one of the three possible values of the resistance of the communication line for each polarity of the voltage or current source. 2. The method according to claim 1, characterized in that the logical signal is transmitted by several parcels of two-digit numbers in a ternary code.