Summary of the invention
In view of this, this application provides a kind of signal be applied in RS-485 communication system and strengthen equipment and RS-485 communication system, for communication node provides drive current, reduce communication failure.
For achieving the above object, the application provides following technical scheme:
First aspect, provide a kind of signal be applied in RS-485 communication system and strengthen equipment, described communication system comprises the multiple RS-485 communication nodes be connected on RS-485 communication bus, described RS-485 communication bus adopts Double wire transmission, each RS-485 communication node is connected to A end and the B end of described RS-485 communication bus respectively, and described signal strengthens equipment and comprises:
Pull-up circuit, pull-down circuit, rectification circuit and accumulator;
Described pull-up circuit holds with the A of described RS-485 communication bus respectively and described accumulator is connected;
Described pull-down circuit holds with the B of described RS-485 communication bus respectively and described accumulator is connected;
Described rectification circuit is held with the A of described RS-485 communication bus respectively, the B of described RS-485 communication bus holds and described accumulator is connected;
Described RS-485 communication bus can be charged to described accumulator by described rectification circuit; Described accumulator can by described pull-up circuit and pull-down circuit to described RS-485 communication bus output current.
Preferably, described rectification circuit comprises the first diode and the second diode;
Described first diodes in parallel is at the two ends of described pull-up circuit;
The positive pole of described first diode is held with the A of described RS-485 communication bus and is connected;
Described second diodes in parallel is at the two ends of described pull-down circuit;
The negative pole of described second diode is held with the B of described RS-485 communication bus and is connected.
Preferably, described rectification circuit comprises the first diode, the second diode, the 3rd diode and the 4th diode;
The positive pole of described first diode holds with the A of described RS-485 communication bus respectively and the negative pole of described 3rd diode is connected, and negative pole is connected with the first end of described accumulator;
The described positive pole of the 3rd diode is connected with the second end of described accumulator;
The positive pole of described second diode is connected with the second end of described accumulator, and negative pole holds with the B of described RS-485 communication bus respectively and the positive pole of described 4th diode is connected;
The negative pole of described 4th diode is connected with the first end of described accumulator;
Wherein, described pull-up circuit is held with the first end of described accumulator and the A of described RS-485 communication bus respectively and is connected;
Described pull-down circuit is held with the second end of described accumulator and the B of described RS-485 communication bus respectively and is connected.
Preferably, described accumulator is made up of N number of electric capacity be connected in series, wherein, N be more than or equal to 1 integer.
Preferably, described pull-up circuit is the first resistance, and described pull-down circuit is the second resistance.
Preferably, described first resistance and described second resistance are respectively 1 kilo-ohm.
Preferably, the capacitance of described electric capacity is 1 microfarad.
Second aspect, provides a kind of RS-485 communication system, comprises being connected to multiple RS-485 communication node on RS-485 communication bus and signal described above strengthens equipment.
Known via above-mentioned technical scheme, compared with prior art, this application provides a kind of signal be applied in RS-485 communication system and strengthen equipment and RS-485 communication system, described signal strengthens equipment connection on RS-485 communication bus, comprise pull-up circuit, pull-down circuit, rectification circuit and accumulator, RS-485 communication bus can be charged to accumulator by rectification circuit; Accumulator can by pull-up circuit and pull-down circuit to RS-485 communication bus output current, and therefore strengthening equipment by described signal can provide drive current to RS-485 communication bus, thus improves the communication capacity of RS-485 communication bus.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
Provide a kind of signal be applied in RS-485 communication system in the embodiment of the present invention and strengthen equipment, described RS-485 communication system comprises the multiple RS-485 communication nodes be connected on RS-485 communication bus, described RS-485 communication bus adopts Double wire transmission, and each RS-485 communication node is connected to A end and the B end of described RS-485 communication bus respectively.
As shown in Figure 1, figure center line A, B are A end and the B end of RS-485 communication bus, and each unit is each communication node, and general master unit 101 refers to main communication node, and subelement 102 refers to sub-communication node.
As shown in Figure 2, be the structural representation of a kind of signal enhancing equipment embodiment be applied in RS-485 communication system that the embodiment of the present invention provides, this signal strengthens equipment and can comprise:
Pull-up circuit 201, pull-down circuit 202, rectification circuit 203 and accumulator 204;
Pull-up circuit 201 holds with the A of RS-485 communication bus respectively and accumulator 204 is connected;
Pull-down circuit 202 holds with the B of RS-485 communication bus respectively and accumulator 204 is connected;
Rectification circuit 203 is held with the A of RS-485 communication bus respectively, the B of RS-485 communication bus holds and described accumulator 204 is connected;
RS-485 communication bus can be charged to accumulator 204 by rectification circuit 203; Accumulator 204 can by pull-up circuit 201 and pull-down circuit 202 to RS-485 communication bus input current.
The signal be applied in RS-485 communication system provided by the invention strengthens equipment, device itself does not comprise supply unit, by rectification circuit, RS-485 communication bus can charge to accumulator when fan-out capability is very strong, and at this moment RS-485 communication node may be in output state; When RS-485 communication bus fan-out capability is not enough, can to RS-485 communication bus Injection Current, to provide drive current.Therefore strengthen equipment by described signal and can provide drive current to RS-485 communication bus, effectively compensate for the problem that signal is decayed at communication node, thus improve the communication capacity of RS-485 communication bus.
RS-485 communication bus can be charged to accumulator 204 by rectification circuit 203, can comprise:
When any one RS-485 communication node is output state, can be charged to accumulator 204 by rectification circuit 203;
Any one RS-485 communication node be input state or high-impedance state time, can by pull-up circuit 201 and pull-down circuit 202 to 203 to RS-485 communication bus input currents.
Common rectifier system can adopt the circuit realiration with diode or triode, provides a kind of rectification circuit can realize technique effect of the present invention here, is also to realize a kind of tandem circuit that can realize this effect of the present invention, as shown in Figure 3:
Rectification circuit comprises the first diode D1 and the second diode D2;
First diode D1 is connected in parallel on the two ends of described pull-up circuit 201;
The positive pole of the first diode D1 is held with the A of described RS-485 communication bus and is connected;
Second diode D2 is connected in parallel on the two ends of described pull-down circuit 202;
The negative pole of the second diode D2 is held with the B of described RS-485 communication bus and is connected.
In this rectification circuit, the described Position Design of two diodes is one stealing circuit cleverly, when RS-485 communication node output current is very capable, electric current is respectively by two diodes, energy storage can be realized to accumulator, when the communication signal transmissions ability of bus is more weak, the electric energy release that accumulator stores, electric current can inject RS-485 communication bus by upper pull-down circuit.
Signal described in Fig. 3 strengthens equipment, can be the pressure reduction of the B terminal voltage of voltage and the RS485 communication bus held at the A of RS485 communication bus, higher than the pressure drop sum of the charging circuit that accumulator and diode are formed, can be charged to accumulator by two diodes.
In another signal enhancing equipment as shown in Figure 4, provide the implementation that the another kind of rectification circuit is possible:
Rectification circuit comprises the 3rd diode D3 and the 4th diode D4;
The positive pole of the 3rd diode D3 is connected with the second end of accumulator; Negative pole is held with the A of RS-485 communication bus and is connected;
The negative pole of the 4th diode D4 is connected with the first end of accumulator; The B end that negative pole connects RS-485 communication bus connects.
Pull-up circuit 201 holds with the A of RS-485 communication bus respectively and the first end of accumulator 204 is connected;
Pull-down circuit 202 holds with the B of RS-485 communication bus respectively and the second end of accumulator 204 is connected;
When RS-485 communication node output current is very capable, electric current, respectively by two diodes, can realize energy storage to accumulator, when the communication signal transmissions ability of bus is more weak, the electric energy release that accumulator stores, electric current can inject RS-485 communication bus by upper pull-down circuit.
Signal described in Fig. 4 strengthens equipment, can be the pressure reduction of the A terminal voltage of voltage and the RS485 communication bus held at the B of RS485 communication bus, higher than the pressure drop sum of the charging circuit that accumulator and diode are formed, can be charged to accumulator by two diodes.
In order to realize better rectification effect, rectification circuit 203 can be designed to further:
As shown in Figure 5, rectification circuit 203 comprises the first diode D1, the second diode D2, the 3rd diode D3 and the 4th diode D4;
The positive pole of the first diode D1 holds with the A of described RS-485 communication bus respectively and the negative pole of described 3rd diode D3 is connected, and negative pole is connected with the first end of described accumulator 204;
The positive pole of the 3rd diode D3 is connected with the second end of described accumulator 204;
The positive pole of the second diode D2 is connected with the second end of described accumulator 204, and negative pole holds with the B of RS-485 communication bus respectively and the positive pole of described 4th diode D4 is connected;
The negative pole of the 4th diode is connected with the first end of described accumulator 204;
Wherein, the link of corresponding pull-up circuit 201 and pull-down circuit 202 and accumulator 201 also will relative to be designed to:
Pull-up circuit 201 is held with the first end of described accumulator 204 and the A of RS-485 communication bus respectively and is connected;
Pull-down circuit 202 is held with the second end of described accumulator 204 and the B of RS-485 communication bus respectively and is connected.
By the embodiment of Fig. 5, the rectification circuit of four diodes ensure that better on the one the second diode bases, can obtain better rectification effect, further ensure electric current under different output mode and have the flow direction determined.
Electric capacity is a kind of very effective accumulator in the circuit of this small components, and the characteristic of the discharge and recharge himself had very effectively can meet the charge-discharge power demand required for the above embodiment of the present invention, so, accumulator can be designed to be made up of electric capacity, but the design of accumulator also has other kinds of schemes according to other common technology means of this area, and being made up of electric capacity is only a kind of preferred version.
Further, accumulator can be made up of N number of electric capacity be connected in series, wherein, N be more than or equal to 1 integer.
In order to realize pull-up or drop-down function, ensureing at accumulator, when output is 1 output circuit, can ensure by the output clamper of accumulator in high level or low level, and play metering function, usually can adopt pull down resistor to realize.
Pull-up circuit in then above-mentioned device is the first resistance R1, and pull-down circuit is the second resistance R2.
Concrete, as shown in Figure 6, to be applied in the device as Fig. 3 by upper pull down resistor as upper pull-down circuit, this device embodiment comprises:
First resistance R1 holds with the A of RS-485 communication bus respectively and accumulator is connected;
Second resistance R2 holds with the B of RS-485 communication bus respectively and accumulator is connected;
First diode D1 is connected in parallel on the two ends of described first resistance;
The positive pole of the first diode D1 is held with the A of described RS-485 communication bus and is connected;
Second diode D2 is connected in parallel on the two ends of described second resistance;
The negative pole of the second diode D2 is held with the B of described RS-485 communication bus and is connected.
When RS-485 communication bus fan-out capability is enough, due to the existence of the rectification circuit that the first and second diodes are formed, RS-485 communication bus can be charged to described accumulator by these two diodes; When RS-485 communication bus needs Injection Current, namely accumulator illustrates electric energy stored by electric capacity C1 by described first resistance and the second resistance to described RS-485 communication bus output current.
In previous embodiment, mention accumulator to be made up of electric capacity, so the accumulator in Fig. 5 has been reduced to the situation of an electric capacity C1, but it should be noted that, realize accumulator required for the present invention and be never only limitted to this kind of scheme meeting, illustrated scheme is just in order to clearly show this embodiment, and the accumulator of an electric capacity can replace with other the accumulator that can realize charge-discharge power demand herein.
As shown in Figure 7, to be applied in the device as Fig. 4 by upper pull down resistor as upper pull-down circuit, this device embodiment comprises:
First resistance R1 holds with the A of RS-485 communication bus respectively and accumulator is connected;
Second resistance R2 holds with the B of RS-485 communication bus respectively and accumulator is connected;
Second end of the positive pole accumulator of the 3rd diode D3 connects; Negative pole is held with the A of RS-485 communication bus and is connected;
The negative pole of the 4th diode D4 is connected with the first end of accumulator, and negative pole is held with the B of RS-485 communication bus and is connected;
First resistance R1 holds with the A of RS-485 communication bus respectively and the first end of accumulator is connected;
Second resistance R2 holds with the B of RS-485 communication bus respectively and the second end of accumulator is connected.
In Fig. 7, accumulator is an electric capacity C1, and certain the present invention does not limit therewith.
As shown in Figure 8, to be applied in the device as Fig. 5 by upper pull down resistor as upper pull-down circuit, this device can comprise:
First resistance R1 holds with the first end of accumulator and the A of RS-485 communication bus respectively and is connected;
Second resistance R2 holds with the second end of accumulator and the B of RS-485 communication bus respectively and is connected.
The positive pole of the first diode D2 holds with the A of described RS-485 communication bus respectively and the negative pole of the 3rd diode is connected, and negative pole is connected with the first end of accumulator;
The positive pole of the 3rd diode D3 is connected with the second end of accumulator;
The positive pole of the second diode D3 is connected with the second end of accumulator, and negative pole holds with the B of RS-485 communication bus respectively and the positive pole of the 4th diode D4 is connected;
The negative pole of the 4th diode D4 is connected with the first end of accumulator.
When RS-485 communication bus fan-out capability is enough, due to the existence of the rectification circuit that four diodes are formed, namely RS-485 communication bus can be charged to described accumulator by this first diode D1, the second diode D2, the 3rd diode D3 and the 4th diode D4.
The pressure reduction of the voltage that concrete can be holds at the A of RS485 communication bus and the B terminal voltage of RS485 communication bus, higher than the pressure drop sum of the charging circuit that accumulator and diode are formed, can be charged to accumulator by the first diode D1 and the second diode D2.
The pressure reduction of the voltage held at the B of RS485 communication bus and the A terminal voltage of RS485 communication bus, higher than the pressure drop sum of the charging circuit that accumulator and diode are formed, can be charged to accumulator by the 3rd diode D3 and the 4th diode D4.
When RS-485 bus requirements Injection Current, namely accumulator illustrates electric energy stored by electric capacity C1 by described first resistance R1 and the second resistance R2 to described RS-485 communication bus output current.
Pull-up circuit is the first resistance R1, be the second resistance R2 with pull-down circuit be only the result as a kind of signal, pull-up circuit and pull-down circuit being applied to Fig. 3 ~ Fig. 5, the program can be applied in the present invention in other embodiments, to other embodiments as further supplementing.
In addition; by resistance as realizing upper drop-down a kind of common approach level being carried out to the scheme of clamper; pull-up circuit provided by the invention is the first resistance; pull-down circuit is the second resistance is only a kind of comparatively easy preferred version that can realize drop-down effect; when not paying creative work; pull-up circuit in the above embodiment of the present invention and pull-down circuit are designed to other common scheme of this area, also should be considered as protection scope of the present invention.
For Fig. 6 ~ embodiment illustrated in fig. 8, concrete provides a kind of resistance data relying on experience and draw here, and general, the first resistance R1 and the second resistance R2 can be 1k Ω; The size of resistance here determines the ability of accumulator to communication bus Injection Current, and the size of 1k Ω is in the apparatus, and can realize a kind of resistance that this device needs the technique effect realized, the resistance of R1, R2 also can be other effective resistance.
Equally, rely on empirically, be made up of N number of electric capacity be connected in series at above-mentioned accumulator, wherein the capacitance of electric capacity can for being 1 μ F, and 1 μ F here is also a kind of preferred version that can realize this contrive equipment effect for RS-485 communication system.
Equipment is strengthened for above-mentioned all signals, by it to be applied to RS-485 communication system, above-mentioned technique effect can be obtained, the communication capacity of this communication system can be significantly improved, other parts of RS-485 communication system with reference to prior art, no longer can be launched herein.
To the above-mentioned explanation of the disclosed embodiments, professional and technical personnel in the field are realized or uses the present invention.To be apparent for those skilled in the art to the multiple amendment of these embodiments, General Principle as defined herein can without departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.