TWI446736B - Method for transmitting discrete electrical signals - Google Patents

Description

Method of transmitting discrete electronic signals

The present invention relates to an information transmission method, and more particularly to a communication interface of an electronic device, and more particularly to a method for transmitting a discrete electronic signal.

http://www.dalsemi.com/www.Dalsemi.com , please also refer to Maxim "DS2409 Micro LAN Coupler", February 7, 2003). Conventionally, it is possible to transmit a discrete electronic signal from a (signal) transmitter end to a receiver end, which is configured in a method having a two-wire communication line of a voltage supply source, wherein the voltage supply The first electrode of the source and the first wire of the communication line are grounded, but the second wire of the communication line is coupled to the second electrode end of the voltage supply through a resistor, which includes A transmitter is used to transmit a logic signal in binary code mode, by using an electronic switch to assist in turning off its line, and the receiver also compares the value of the voltage it reads with the value of the ground. Here, the logic 0 signal is generally considered to have a voltage level in the communication line that is lower than the first predetermined threshold (Threshold), and the logic 0 signal is generally considered to be higher than a predetermined threshold. . Typically, the system will choose to correspond to the logical TTL level with 0.8V and 1.2V and be treated as the critical value described above. In addition to the micro-LAN interface, many other conventional interfaces have been constructed using the same method.

The conventional method allows a large number of devices to be connected to each other and which can provide signals in a bidirectional manner in more than two wires, and can also provide power by using a power supply device of the communication line. This will reduce the cost of building the method.

A disadvantage of the conventional method for transmitting discrete electronic signals is that their noise (noise) suppression capability is low. When it is affected by noise (noise), although its effect is the same for the two wires, the result of its effect is different. This difference is due to its presence in the communication line. The noise (noise) propagation conditions in grounded and ungrounded wires are different. It is clear that the difference is mainly due to the resistance value of the noise (noise) current circulating in each wire. The position affected by noise (noise) is pointed to the electrode end of the power supply, or the grounding point. As a result, a location point affected by noise (noise), and other sections in the communication line, will exhibit a voltage difference, which is the noise (noise) voltage, which will prevent it from being required. The signal can be transmitted in an appropriate manner.

The method closest to the scope of the patent application disclosed in the present invention, which is technically and achievable, can be used to transmit an electronic signal from a (signal) transmitter to a receiver, the receiver being Connected to a two-wire communication line having a communication line voltage supply source, wherein the signal read by the signal is determined to be a logic 0 and a logic 1 signal, depending on the level of the signal in the communication line. Comparing a preset threshold, the receiver has a current sensor installed in the communication line between the communication line voltage supply source and the nearest distance therein At the position between the transmitters, since the output resistors have been changed and can be known by the current value measured by the current sensor, each set of (signal) transmitters has one A built-in second power supply capable of supplying power through the communication line (International Patent Publication No. WO 2009/067037, International Patent Application Date, September 12, 2007).

Conventional methods for transmitting discrete electronic signals maintain communication operations between a single communication line to a large number of (signal) transmitters, provided that the (signal) transmitter can provide power by an external power source. A disadvantage of the conventional method is that it does not allow power to be supplied from a communication line to a large number of (signal) transmitters, or to allow configuration of a high energy (signal) transmitter. The (signal) transmitter typically supplies power through a capacitor that is powered from a communication line and via a gate (diode). This will ensure that the power supply to the (signal) transmitter is not interrupted during the execution of the signal transmission, even when a voltage drop occurs in the communication line.

When a communication line is used to provide power for some (signal) transmitters by means of the communication line, the above (signal) transmitter can only select a small number, which is due to the (signal) The total current value of the transmitter's power supply is severely limited: when one of the (signal) transmitters is transmitting a signal, the current generated by the transmitter to transmit the signal is greater than the current value of the item. A lot lower. This is due to the following causal chain reaction during signal transmission.

The current that can flow through the current sensor is not included in the transmission signal, and its value is large. Small equal to the total current value of the power supply to the (signal) transmitter. When it is first seen, it seems to be because, because a signal is being transmitted, the signal transmission current must be added to the current value of the power supply of the (signal) transmitter, so the current sensor will be marked to one phase. Different current values. This may be true in this case if the resistance value of the communication line wire is equal to zero. However, the communication line wire has a limited resistance value, and one of the signal transmission currents is passing, so the voltage value in the communication line will decrease. As a result, other (signal) transmitters will temporarily stop receiving power from the communication line and must switch to their second (built-in, usually capacitor) power supply to provide power, also That is, during the transmission of the signal, the power supply of the (signal) transmitter determines that the current value that must be supplied to the communication line is lower than the current value that must be added to transmit the signal, and the two current values are At the same time offset. At the same time, a total current value flowing through the current sensor remains unchanged; therefore, the current signal transmitted from the (signal) transmitter will not be sent to the receiver. It must wait until the current value available to perform the signal transmission is sufficient to exceed the total current value of the power supply of the (signal) transmitter, and the voltage value in the communication line will fall below its lowest static voltage value. This will cause the power supply to be turned off for all (signal) transmitters in a communication line, and will result in a further increase in the current value required for its signal transmission, so the signal in the current sensor will Start to increase. Therefore, the current value required for signal transmission is compensated by the current of the (signal) transmitter power supply, and in order to obtain stability during data communication transmission. Sex, the current value used for signal transmission must be much higher than the current value that the (signal) transmitter power supply can provide. Considering that the total current value in a communication line must be limited to prevent a specific negative wave from being generated in the communication line, which also limits the total current value of the (signal) transmitter power supply. And, therefore, it also leads to limiting the number of installations. In addition, the signal value in the current sensor is spread over a wide range, that is, the full view depends on the setting position of the (signal) transmitter in a communication line: the closest to the current sense The (signal) transmitter of the detector has a larger signal value when it feels that the effect of current compensation is minimal.

Therefore, how to improve the shortcomings of the above-mentioned practices is the concern of this case.

In the present invention, it is achieved that the number of (signal) transmitters powered by a communication line can be increased, the length of the communication line can be increased, and the signal values transmitted from the transmitters at different locations can be uniformized. If the communication line has a power consumption drop condition.

A specific target will be successfully achieved. One method is to transmit a discrete electronic signal from at least one (signal) transmitter to a receiver, the receiver being connected to a two-wire type having a voltage supply. On the communication line, the signal read in the communication line is recognized as a logic 0 and 1, and the receiver is compared according to the result of comparing the signal level in the communication line with a preset threshold. One of the current sensors is installed in the communication line between the communication line voltage supply source At the position between the transmitter and the nearest transmitter, when the transmitter performs the signal transmission action, the current in the communication line will be changed accordingly, since the output resistor has been changed and can be Knowing the current value measured by the current sensor, each set of (signal) transmitters each have a built-in second power supply that can provide power through the communication line, and before starting to transmit signals, The voltage value of the communication line power supply will drop first and will return to its original state after the signal transmission is completed.

Preferably, when no signal is available for transmission, the voltage of the communication line power supply drops to a value which is lower than the lowest static voltage value of the entire communication line length (the lowest of the communication lines) The voltage value is observed from the end furthest from the communication line power supply). In other words, one might say that when there is no signal available for transmission, the voltage drop of the communication line power supply voltage is at least equal to the voltage drop that falls along a communication line. Here, the voltage of the communication line power supply does not drop to zero; instead, it drops to a reasonable value, which is sufficient for the (signal) transmitter to generate a current signal in the communication line. This enables the signal receiver current sensor to determine the electromagnetic noise and signal loss that may occur in the background due to the wave processing of the communication line. Once the acceptable minimum value of the signal is determined, this is, according to Ohm's law, the value is multiplied by a resistor value, which is from the communication line power supply and the distance from the power source. Measured in the section between the transmitters furthest from the supplier. Then calculate the calculated value Adding a voltage drop that may appear in the active portion of the (signal) transmitter, depending on how it is designed, the result will correspond to the lowest acceptable voltage drop for the communication line power supply. . By selecting the appropriate system parameters, this voltage, as previously described, when no signal is available for transmission, this voltage value must never exceed the lowest static voltage value measured along the entire length of the communication line. It is therefore the best solution to pick the largest possible voltage value from the best range of values it can obtain.

Preferably, each of the (signal) transmitters comprises a capacitor which can be regarded as a built-in second power supply and can be connected to a communication line through a set of diodes.

The essence of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a wiring line, a voltage supply source, a (signal) transmitter and a receiver wiring used in the method of the preferred embodiment of the present invention. Figure.

Figure 2 is a voltage waveform diagram of the (signal) transmitter N from the voltage supply source end to the farthest distance along the length of the communication line L.

1 is a diagram showing the structure of a communication line. For simplification, only three sets of (signal) transmitters of the same design are included; however, for the application of the present invention, it is conceivable to substantially increase the (signal) transmitter. The number of installations, for example, is up to 256 groups. For the substance disclosed in the present invention, the following conventional formulas will be used in FIG. 1: 1 for power supply; 2 for two-wire communication line; 3 for (signal) receiver; a microprocessor representing a receiver; 5 for a current sensor; 6, 12, ... N for a signal transmitter; 7, 13, 18 for a (signal) transmitter diode; 8, 14, 19 for a capacitor that is a built-in second power supply for a (signal) transmitter; 9, 15, 20 for a (signal) transmitter microprocessor; 10, 16, 21 for a (signal) transmitter switch; 11, 17, 22 represent resistors sufficient to limit (signal) transmitter functionality.

In Figure 2, the coordinates "0" correspond to the power and current sensor positions, and the position N corresponds to the position of the (signal) transmitter that is furthest from the power source. The positions (coordinates) of a series of N sets of (signal) transmitters are designated 6, 12, 23, 24, 25, 26, 27, ..., N, respectively.

The dotted line in Fig. 2 is used to display the voltage waveform of the communication line, which shows that the voltage of the power supply 1 has temporarily dropped to a value of 5V, 4.5V and 3.3V. With continued reference to FIG. 2, when a voltage drop occurs, the (signal) transmitter that is powered by the communication line and is placed near the power supply location: its voltage drops to 5V, and these (signal) transmissions The devices are 6, 12, and 23, and the voltage drops to 4.5V, including the transmitter-added (signal) transmitters 24, 25, and 26, and the voltage system drops to 3.3V. All (signal) transmitters in the communication line.

The essence of the present invention resides in the following items.

The (signal) transmitters 6, 12, ..., N, etc. provide power by the communication line 2, and the current of their power supplies causes a generation in the communication line 2 The voltage drop; therefore, it can be observed that the lowest power supply voltage will appear at the N-end of the (signal) transmitter, which is placed at the farthest distance from the power supply 1. In this method, the voltage of the power supply 1 drops briefly (when the (signal) transmitters 6, 12, ... N, etc. start transmitting electronic signals). During this period, the power supply of the (signal) transmitter having a higher voltage will be cut off by the diodes 7, 13, 18 of the communication line 2 and will be switched to be replaced by their own built-in type. Two power supplies (capacitors 8, 14, 19) are provided to provide power. Here, once a signal is transmitted (starting (signal) the switches of the transmitters 10, 16, 21), the current value in the communication line 2 marked by the current sensor 5 can still be passed through at that time. The communication line provides the current consumed by the power (signal) transmitter to determine, that is, those transmitters whose voltage values do not drop in the communication line (see Figure 2). In the final case, if the voltage value in the communication line 2 drops below the voltage level of the transmitter N (which is placed at the farthest distance from the power source 1) having the lowest power supply voltage value, once When a signal is transmitted, the (signal) transmitters 6, 12, ... N will be completely powered down, so that no current will pass through the current sensor 5.

If a signal 0 is transmitted through one of the transmitter terminals, such as the transmitter 12, its microprocessor 15 will shut down the communication line 2 via the resistor 17 and using the switch 16, so that The transmitter that transmits a signal generates a current. Here, the current sensor 5 will only mark the current associated with the signal transmission. When the signal transmission is performed, the voltage value in the communication line 2 will be Yes, under the influence of this current, the decline will further lead to the fact that all (signal) transmitters will be cut off even if the power supply status is maintained.

Therefore, when transmitting a signal 0, the current sensor 5 marks the current of the (signal) transmitter 12 that is performing the signal transmission, but when transmitting a signal 1, it will mark The current of the (signal) transmitter power supply is still supplied by the communication line 2. In the event that the current value of the (signal) transmitter 12 performing the signal transmission is lower than the current value of the (signal) transmitter power supply that still obtains the power supply from the communication line 2, the result of the current compensation described above The current value flowing through the current sensor 5 will remain unchanged. In case the signal transmission current of the (signal) transmitter 12 is higher than the current value of the (signal) transmitter power supply that still obtains power supply from the communication line 2, the current sensor 5 will mark A surge of current is equal in magnitude to the current overload of one of the signal transmissions using the current of the (signal) transmitter power supply that is still receiving power from the communication line 2 end. This (current) spur is still generated even if all the currents of all (signal) transmitter power supplies are in a stationary state, that is, before the power supply 1 generates a voltage drop, the system is higher than The current value at which the signal transmission is performed. In other words, due to the application of the present invention, the current value of the currently recorded executable signal transmission will be much higher than the current value of the (signal) transmitter power supply obtained by a communication line. . This is simply not possible in a prototype that operates in static mode. This move The current value of the (signal) transmitter power supply can be increased, that is, the number of installations of these (signal) transmitters can be increased in the communication line 2.

At the same time, it is worthy of attention that for all (signal) transmitters 6, 12, ..., N, etc. connected to a communication line, when transmitting a signal 0, the current values used are the same, Ensure the stability and regenerative communication capabilities of all (signal) transmitters connected to the communication line 2.

The essence of the method of transmitting discrete electronic signals to a receiver end along a two-wire communication line from a (signal) transmitter end ensures communication performance and can be targeted in a communication line ( The transmitter) is configured with a larger number of power supplies, which can be illustrated by way of an example of one embodiment of the invention without limiting the scope of the patent application.

Example 1

The electric wire of the two-wire communication line 2 is connected to the electrode end of the power source 1 whose voltage is 5.6 V, as shown in FIG. The wires of the communication line 2 are connected to the receiver 3 and the (signal) transmitters 6, 12, ..., N, etc., and the receiver 3 is installed in the (signal) transmitters 6, 12, ..N and the position between the power source 1. Here, the N system can take any value, for example, 256.

The microprocessor 4 included in the receiver 3 can be coupled to the current sensor 5 mounted on the wires of the communication line 2.

The (signal) transmitters 6, 12, ... N are all of the same design and package The microprocessors 9, 15, ... 20 are respectively provided with electric power through the capacitors 8, 14, ..., respectively, where the capacitors are respectively connected to the diodes 7 of the communication line 2, 13,...18 to charge. The (signal) transmitters 6, 12, ... N are each provided with an output configured in the form of switches 10, 16, ... 21 that can be manipulated via microprocessors 9, 15, ... 20 platform. During the transmission of the signal, the current of the communication line 2 must be maintained at a predetermined value, during which the switch is coupled to the communication line through a limited number of resistors 11, 17, 22... 2 end.

In the normal state, the communication line 2 corresponds to a logic 1 signal transmission operation, where the voltage value in the communication line 2 is the voltage value of the power source 1 and the signal (by the signal) The magnitude of the power supply current of the transmitters 6, 12, ... N is closely related to a voltage drop at the line end of the communication line 2. As a result of the measurement, it was found that the voltage value at the installation position of the farthest (signal) transmitter N in the communication line 2 was 3.5V.

By turning off the switch 16 before starting the transmission of the signal, the voltage of the power supply 1 drops to a voltage of 4.5V, that is, lower than the voltage value of the power supply (5.6V), but slightly exceeds the The minimum voltage value of the communication line (3.5V). Here, the (signal) transmitter disposed in the communication line 2 whose voltage value has decreased (located in the communication line 2 at a position close to the power supply voltage supply source 1 as shown in FIG. 2 The above-mentioned systems including the (signal) transmitters 6, 12, 23, 24, 25 and 26) are cut off from the power supply of the communication line 2. The supplied power: and their diodes 7, 13, ... are turned off and the operational functions of the capacitors 8, 14, ... from the communication line 2 having the power supply function are stopped. The (signal) transmitters 6, 12, 23, 24, 25 and 26) are switched to provide power by their own built-in second power supply - the capacitors 8, 14, ... The current value of the communication line 2 will drop (this current value corresponds to the transmission operation of a signal one). By generating a logic 0 signal, the switch 16 of one of the (signal) transmitters 12 is turned off by a limited number of resistors 17 due to the current in the communication line 2, thus The current sensor 5 will mark a current surge whose value is equal to a difference between the current value that can be used to transmit a signal 0 and the current value that can be used to transmit a signal 1 (the signal) The current of the transmitter power supply can still be supplied with power).

Example 2

One of the communication lines 2 used herein is designed in the same manner as the one used in Example 1.

By turning off the switch 16 before starting the transmission of the signal from the (signal) transmitter 12, the voltage of the power supply 1 drops to a voltage of 3.3 V, that is, what is known to us is lower than the communication. The lowest voltage value of the line (3.5V). Here, the diodes 7, 13, ... 18 are turned off and the operational functions of the capacitors 8, 14, ... 19 having power supply functions from the communication line 2 are stopped, at which time the (signal) transmitter 6, 12, ... N4 will be switched to be built by their own built-in second The power supply - the capacitors 8, 14, ... 19 provide power, and the current of the communication line 2 is completely stopped. After that, the signal transmission operation can be performed by one of the (signal) transmitters 12 of a limited number of resistors 17 and thereby the switch 16 is turned off, thereby being generated by the communication line 2. The current is briefly generated by a logic 0 signal. As a result of a drop in the supply voltage, the current sensor 5 will only mark the current generated by the switch 16 and will not be subjected to currents generated by the (signal) transmitters 6, 12, N, etc. interference.

Based on the above facts, the benefits provided by the present invention include the (signal) transmitter power supply that can be simultaneously circulated along the communication line as a result of a brief voltage drop in the communication line. The current is isolated from the current required for signal communication. This will reduce the total current value in the communication line, thus allowing an application with a higher resistance value (up to 500 ohms in the embodiment) to be employed in a communication line. This means that it is possible to increase the length of a communication line and reduce the cost of its signal communication: reducing the cross-sectional area of the wire, the storage capacity of the battery, and the power of the power supply. If the current load of the communication line can be reduced, the (signal) transmitter can be operated with a higher current consumption, that is, the (signal) transmission for supplying power from the communication line can be increased. The allowable number of devices increases the distance and reliability of the communication transmission, and also obtains better signal reception conditions, because it can uniformize the current from the signals transmitted by the (signal) transmitters at different locations. value.

1‧‧‧Power supply

2‧‧‧Communication lines

3‧‧‧ (signal) receiver

4‧‧‧Receiver microprocessor

5‧‧‧ Current sensor

6‧‧‧ (signal) transmitter

7‧‧‧ diode

8‧‧‧ capacitor

9‧‧‧Transmitter microprocessor

10‧‧‧ switch

The essence of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a wiring line, a voltage supply source, a (signal) transmitter and a receiver wiring used in the method of the preferred embodiment of the present invention. Figure.

Figure 2 is a voltage waveform diagram of the (signal) transmitter N from the voltage supply source end to the farthest distance along the length of the communication line L.

1‧‧‧Power supply

2‧‧‧Communication lines

3‧‧‧ (signal) receiver

4‧‧‧Receiver microprocessor

5‧‧‧ Current sensor

6‧‧‧ (signal) transmitter

7‧‧‧ diode

8‧‧‧ capacitor

9‧‧‧Transmitter microprocessor

10‧‧‧ switch

Claims (3)

A method for transmitting a discrete electronic signal, which can be used to transmit an electronic signal from at least one transmitter to a receiver, the receiver being connected to a two-wire communication line having a voltage supply source by the communication The signal level read in the line determines logic 0 and 1, and the logic 0 and 1 correspond to a preset threshold. The receiver can use a current sensor for the current sensing. The device is installed in the communication line between the voltage supply source and the nearest transmitter; the step includes: changing the current in the two-wire communication line when the transmitter performs the signal transmission operation; wherein the current is The change system uses the change of the output resistor; the current value of the two-wire communication line is sensed by using two sensors; wherein each of the transmitters has a built-in charge through the communication line (Charge) The second power supply, and the voltage value of the communication line power supply will drop first before starting to transmit the signal, and will be restored after the signal transmission is completed. The method of claim 1, wherein when no signal is available for transmission, the voltage of the power supply of the communication line is reduced to a value which is lower than the lowest static voltage value of the entire communication line length. Lower. The method of claim 1, wherein the capacitor included in each of the transmitters is configured as the built-in second power supply and can be coupled to the communication line through a diode.