CN210015164U - Electric energy meter and RS485 communication system thereof - Google Patents
Electric energy meter and RS485 communication system thereof Download PDFInfo
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- CN210015164U CN210015164U CN201920638351.3U CN201920638351U CN210015164U CN 210015164 U CN210015164 U CN 210015164U CN 201920638351 U CN201920638351 U CN 201920638351U CN 210015164 U CN210015164 U CN 210015164U
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Abstract
The utility model discloses an electric energy meter and RS485 communication system thereof, which is applied to the electric energy meter, comprising an isolated RS485 chip which is respectively connected with an external processor and a power supply, and is used for converting TTL level signals sent by the external processor into differential signals and then sending the differential signals through an interface circuit, converting the differential signals received through the interface circuit into TTL level signals and then sending the TTL level signals to the external processor, and also used for isolating current flowing to the external processor from the interface circuit; an interface circuit; and the first power supply is used for supplying power to the isolated RS485 chip. Owing to only adopt the utility model provides an isolated RS485 chip alright replace RS485 chip and optoelectronic coupler circuit among the original RS485 communication system, reduced the quantity of electronic components among the RS485 communication system in a large number, simplified the manufacturing procedure of circuit board, improved work efficiency, reduced manufacturing cost.
Description
Technical Field
The utility model relates to an electric energy meter field especially relates to a RS485 communication system, the utility model discloses still relate to an electric energy meter.
Background
The RS485 communication system can be applied to a plurality of fields, which is an indispensable component in the communication mode of the electric energy meter, in the prior art, an RS485 chip in the RS485 communication system can be used for converting TTL level signals sent by a processor into differential signals and then sending the differential signals, and can also convert received differential signals into TTL level signals and then transmitting the TTL level signals to the processor, in order to prevent the processor from being damaged by strong current, a photoelectric coupler circuit is usually arranged on each pin connected between the RS485 chip and the processor for photoelectric isolation so as to protect the processor, but under the condition, the number of electronic components in the RS485 communication system is large, the manufacturing flow of a circuit board becomes complex, the working efficiency is reduced, and the manufacturing cost is improved.
Therefore, how to provide a solution to the above technical problem is a problem that needs to be solved by those skilled in the art.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing an RS485 communication system, simplifying the manufacturing process of the circuit board, improving the working efficiency and reducing the manufacturing cost; another object of the utility model is to provide an electric energy meter including above-mentioned RS485 communication system has simplified the manufacturing procedure of circuit board, has improved work efficiency, has reduced manufacturing cost.
In order to solve the technical problem, the utility model provides a RS485 communication system is applied to the electric energy meter, include:
the isolation RS485 chip is respectively connected with the external processor and the power supply, and is used for converting TTL level signals sent by the external processor into differential signals and then sending the differential signals out through the interface circuit, converting the differential signals received through the interface circuit into TTL level signals and then sending the TTL level signals to the external processor, and is also used for isolating current flowing from the interface circuit to the external processor;
the interface circuit;
and the first power supply is used for supplying power to the isolated RS485 chip.
Preferably, the interface circuit comprises a pull-up resistor, a pull-down resistor, a second power supply, a protection circuit and a wiring terminal;
the pull-up resistor is respectively connected with the first differential signal output end of the isolated RS485 chip and the second power supply and is used for clamping the differential signal output by the first differential signal output end at a high level;
the first end of the pull-down resistor is connected with the second differential signal output end of the isolated RS485 chip, and the second end of the pull-down resistor is grounded with the first differential signal output end of the isolated RS485 chip and is used for clamping the differential signal output by the second differential signal output end at a low level;
the protection circuit is respectively connected with the first differential signal output end, the second differential signal output end and the wiring terminal of the isolation type RS485 chip and is used for absorbing external strong electricity to protect the isolation type RS485 chip.
Preferably, the protection circuit is a surge current absorbing device for absorbing an external surge current;
the first end of the surge current absorption device is connected with the first differential signal output end and the wiring terminal respectively, and the second end of the surge current absorption device is connected with the second differential signal output end and the wiring terminal respectively.
Preferably, the surge current absorbing device is a bidirectional transient suppression TVS diode.
Preferably, the protection circuit further comprises a first voltage-dividing resistor and/or a second voltage-dividing resistor;
a first end of the first voltage-dividing resistor is connected with a first end of the surge current absorption device and the first differential signal output end respectively, and a second end of the first voltage-dividing resistor is connected with the wiring terminal;
the first end of the second voltage-dividing resistor is connected with the second end of the surge current absorption device and the second differential signal output end respectively, and the second end of the second voltage-dividing resistor is connected with the wiring terminal.
Preferably, the first voltage-dividing resistor and the second voltage-dividing resistor are both thermistors.
Preferably, the first power supply is a two-way isolated power supply.
Preferably, the RS485 communication system further comprises:
the prompter is connected with the isolated RS485 chip;
the isolated RS485 chip is further configured to control the prompter to prompt that the signal conversion is being performed while performing the signal conversion.
Preferably, the isolated RS485 chip is an IOS1500 type isolated RS485 chip.
In order to solve the technical problem, the utility model also provides an electric energy meter, include as above arbitrary RS485 communication system.
The utility model provides a RS485 communication system, which is applied to an electric energy meter, and comprises an isolated RS485 chip which is respectively connected with an external processor and a power supply, and is used for converting TTL level signals sent by the external processor into differential signals and then sending the differential signals through an interface circuit, converting the differential signals received through the interface circuit into TTL level signals and then sending the TTL level signals to the external processor, and also used for isolating current flowing to the external processor from the interface circuit; an interface circuit; and the first power supply is used for supplying power to the isolated RS485 chip.
It can be seen, the utility model provides an isolated RS485 chip can accomplish TTL level signal and difference signal's interconversion and send work simultaneously, and this isolated RS485 signal can also keep apart the electric current that flows to outside treater by interface circuit so that protect outside treater simultaneously, owing to only adopt the utility model provides an isolated RS485 chip alright replace RS485 chip and optoelectronic coupler circuit among the original RS485 communication system, reduced the quantity of electronic components among the RS485 communication system in a large number, simplified the manufacturing procedure of circuit board, improved work efficiency, reduced manufacturing cost.
The utility model also provides an electric energy meter has the same beneficial effect of above RS485 communication system.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required in the prior art and the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an RS485 communication system provided by the present invention;
fig. 2 is a schematic structural diagram of another RS485 communication system provided by the present invention.
Detailed Description
The core of the utility model is to provide an RS485 communication system, which simplifies the manufacturing process of the circuit board, improves the working efficiency and reduces the manufacturing cost; the utility model discloses an another core provides an electric energy meter including above-mentioned RS485 communication system, has simplified the manufacturing procedure of circuit board, has improved work efficiency, has reduced manufacturing cost.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an RS485 communication system according to the present invention, including:
the isolation RS485 chip 1 is respectively connected with the external processor and the power supply, and is used for converting TTL level signals sent by the external processor into differential signals and then sending the differential signals out through the interface circuit 2, converting the differential signals received through the interface circuit 2 into TTL level signals and then sending the TTL level signals to the external processor, and isolating current flowing from the interface circuit 2 to the external processor;
an interface circuit 2;
and the first power supply 3 is used for supplying power to the isolated RS485 chip 1.
In particular, the isolated RS485 chip 1 has various types, and in the field of electric energy meters, the isolated RS485 chip 1 has been developed and produced, and can not only complete the signal conversion work that a common RS485 chip can complete (TTL level signal sent by an external processor is converted into a differential signal and then sent out through an interface circuit 2, and the differential signal received through the interface circuit 2 is converted into a TTL level signal and then sent to the external processor), but also isolate the current flowing from the interface circuit 2 to the external processor, in this case, the isolated RS485 chip 1 can protect the external processor by using its own isolation function, and the isolated 485 chip can replace the original photoelectric isolator circuit and RS485 chip, thereby greatly reducing the number of components, simplifying the manufacturing process of the circuit board, and improving the working efficiency, the manufacturing cost is reduced.
When the isolated RS485 chip 1 is fixed on the circuit board, all the pins of the chip are connected with the power supply, the external processor and the interface circuit 2, so that the workload is greatly reduced, and the working efficiency is improved.
Specifically, under the general condition, the volume of isolation RS485 chip 1 is less than the total volume of original photoelectric isolator circuit and RS485 chip, that is to say the utility model provides an in the embodiment the shared circuit board of RS485 communication system area also reduced, reduced the volume of components and parts quantity and circuit board simultaneously, also reduced the use of material, practiced thrift the resource.
Wherein, interface circuit 2 can be connected with the RS485 bus usually, and the convenience is transmitted differential signal, and its concrete structure can have a lot of types, the embodiment of the utility model provides a do not limit here.
Wherein, first power 3 can provide its required electric energy for isolated RS485 chip 1 to the RS485 chip normally works.
The utility model provides a RS485 communication system, which is applied to an electric energy meter, and comprises an isolated RS485 chip which is respectively connected with an external processor and a power supply, and is used for converting TTL level signals sent by the external processor into differential signals and then sending the differential signals through an interface circuit, converting the differential signals received through the interface circuit into TTL level signals and then sending the TTL level signals to the external processor, and also used for isolating current flowing to the external processor from the interface circuit; an interface circuit; and the first power supply is used for supplying power to the isolated RS485 chip.
It can be seen, the utility model provides an isolated RS485 chip can accomplish TTL level signal and difference signal's interconversion and send work simultaneously, and this isolated RS485 signal can also keep apart the electric current that flows to outside treater by interface circuit so that protect outside treater simultaneously, owing to only adopt the utility model provides an isolated RS485 chip alright replace RS485 chip and optoelectronic coupler circuit among the original RS485 communication system, reduced the quantity of electronic components among the RS485 communication system in a large number, simplified the manufacturing procedure of circuit board, improved work efficiency, reduced manufacturing cost.
For better explaining the embodiments of the present invention, please refer to fig. 2, fig. 2 is a schematic structural diagram of another RS485 communication system provided by the present invention, and on the basis of the above embodiments:
as a preferred embodiment, the interface circuit 2 includes a pull-up resistor R1, a pull-down resistor R2, a second power supply, a protection circuit, and a connection terminal;
the pull-up resistor R1 is respectively connected with the first differential signal output end of the isolated RS485 chip 1 and a second power supply, and is used for clamping the differential signal output by the first differential signal output end at a high level;
the first end of the pull-down resistor R2 is connected with the second differential signal output end of the isolated RS485 chip 1, and the second end of the pull-down resistor R2 is grounded with the first differential signal output end of the isolated RS485 chip 1 and is used for clamping the differential signal output by the second differential signal output end at a low level;
the protection circuit is respectively connected with the first differential signal output end, the second differential signal output end and the wiring terminal of the isolation type RS485 chip 1 and used for absorbing external strong electricity to protect the isolation type RS485 chip 1.
Specifically, the RS485 standard definition signal has a certain threshold range, for example, the upper and lower limits of the threshold of the RS485 standard definition signal are ± 200mV, that is, when the difference between two differential signals is greater than 200mV, the bus state should be represented as "1"; when the difference value of the two differential signals is not more than 200mV, the bus state is represented as "0", but when the difference value of the two differential signals is within +/-200 mV, the bus state is uncertain, so an up-down resistor R2 is arranged on the A, B line to avoid the uncertain state as much as possible.
In fig. 2, the first power supply 3 may be VCC and V485, and the specific values of the devices in fig. 2 are only an example, and the specific values may also be other various values.
Specifically, the second power source may be one of the power sources in the first power source 3, for example, V485 in fig. 2, and of course, the second power source may also be another additional independent power source, and the embodiment of the present invention is not limited herein.
Wherein, the voltage of second power can independently set for according to actual demand, the embodiment of the utility model provides a do not limit here.
Specifically, the resistance of pull-up resistor R1 and pull-down resistor R2 can be set independently according to actual needs, and the embodiment of the present invention is not limited herein.
Specifically, because there is potential harm such as surge impact, power cord and 485 line short circuits, thunderbolt on the RS485 bus often, so the embodiment of the utility model provides an in, set up protection circuit at RS485 bus end, protection circuit can absorb other devices such as external forceful electric power in order to protect isolated RS485 chip 1 and not receive the damage, and its concrete structure can be multiple type, the embodiment of the utility model provides a do not limit here.
Certainly, in the embodiment of the utility model provides an in also can not set up protection circuit, normal work can be accomplished equally to RS485 communication system.
Wherein, binding post can convenience of customers with RS485 bus connection to RS485 communication system on, it can be multiple type, the embodiment of the utility model provides a do not limit here.
As a preferred embodiment, the protection circuit is an inrush current absorbing device VD2 for absorbing an external inrush current;
the first end of the surge current absorbing device VD2 is respectively connected with the first differential signal output end and the wiring terminal, and the second end of the surge current absorbing device VD2 is respectively connected with the second differential signal output end and the wiring terminal.
Specifically, because binding post belongs to RS485 communication system's external interface, consequently under a large number of uncertain circumstances, the external world probably has the forceful electric power to flow in RS485 communication system and cause the destruction to relevant components and parts wherein through binding post, the embodiment of the utility model provides an in surge current absorption device VD2 can be when surge current is received in the external world, can absorb the heavy current in the twinkling of an eye, strangulates the voltage at self both ends on a predetermined numerical value to the circuit component at the protection back does not receive the impact of transient state high voltage spike pulse.
The surge current absorbing device VD2 may be of various types, and the embodiment of the present invention is not limited herein.
As a preferred embodiment, the surge current absorbing device VD2 is a bidirectional TVS (Transient voltage suppressor) diode.
Specifically, the bidirectional TVS diode has the advantages of simple structure, small volume, low price and the like;
of course, the surge current absorbing device VD2 may be of other types besides the bidirectional TVS diode, and the embodiment of the present invention is not limited herein.
As a preferred embodiment, the protection circuit further includes a first voltage dividing resistor RT1 and/or a second voltage dividing resistor;
a first end of a first divider resistor RT1 is respectively connected with a first end of the surge current absorbing device VD2 and a first differential signal output end, and a second end of the first divider resistor RT1 is connected with a connecting terminal;
the first end of the second voltage-dividing resistor is connected with the second end of the surge current absorbing device VD2 and the second differential signal output end, respectively, and the second end of the second voltage-dividing resistor is connected with the connection terminal.
Specifically, first divider resistor RT1 and second divider resistor can be used for undertaking partial voltage on the difference signal path that corresponds separately respectively to prevent that external big voltage from causing the destruction to the inside device of RS485 communication system, can set up one of them or two according to actual demand and set up, the embodiment of the utility model provides a do not do the restriction here.
Wherein, the resistance of first divider resistance RT1 and second divider resistance can independently set for according to the actual demand, the embodiment of the utility model provides a do not limit here.
In a preferred embodiment, the first voltage dividing resistor RT1 and the second voltage dividing resistor are thermistors.
Specifically, the embodiment of the utility model provides an in can choose for use positive temperature coefficient thermistor, thermistor has advantages such as sensitivity height, operating temperature range width, small and overload capacity are strong.
Of course, the first voltage dividing resistor RT1 and the second voltage dividing resistor may be other types of resistors besides the thermistor, and the embodiment of the present invention is not limited herein.
As a preferred embodiment, the first power supply 3 is a two-way isolated power supply.
Specifically, the isolated power supply is characterized in that input and output are electrically connected through magnetic components such as a transformer, related components cannot be damaged even if the output is short-circuited, and the safety is high.
Wherein, the two-way isolation power supply can be simultaneously by two way two power supply pins of connecting isolation formula RS485 chip 1, still can set up a filter capacitance respectively for two power supplies, like C1 and C2 in fig. 2, it can the filtering power supply noise, and during the overall arrangement, filter capacitance should be close to the power supply pin setting that corresponds respectively.
Of course, the first power source 3 may be of other types besides the two-way isolated power source, and the embodiment of the present invention is not limited herein.
As a preferred embodiment, the RS485 communication system further includes:
the prompter is connected with the isolated RS485 chip 1;
the isolated RS485 chip 1 is also used for controlling the prompter to prompt that the signal conversion is performed at the same time of performing the signal conversion.
It is specific, consider that isolated RS485 chip 1 probably breaks down and can't work under some circumstances, the embodiment of the utility model provides an RS485 chip can be when carrying out signal conversion, control prompting device suggestion self is carrying out signal conversion, under this kind of circumstances, the staff can learn the inside working condition of isolated RS485 chip 1 through the prompting device, if when isolated RS485 chip 1 should carry out signal conversion, the prompting device does not indicate isolated RS485 chip 1 and is carrying out signal conversion, can confirm RS485 chip trouble or prompting device trouble so, the staff can overhaul isolated RS485 chip 1 rapidly, has improved work efficiency.
The prompting device may be of various types, for example, may be a light emitting diode, and the embodiment of the present invention is not limited herein.
As a preferred embodiment, the isolated RS485 chip 1 is an IOS1500 type isolated RS485 chip.
Specifically, the IOS1500 type isolated RS485 chip has the advantages of strong stability, high safety, small size and the like.
Compared with a traditional photoelectric coupler circuit and an RS485 communication system of an RS485 chip, the IOS1500 type isolation RS485 chip can reduce circuit board space by 85%, in addition, the IOS1500 type isolation RS485 chip adopts a semiconductor manufacturing process, silicon dioxide is used as a dielectric, the difference between devices is reduced to the maximum extent, more reliable high-voltage resistance performance is provided, the high-voltage isolation type IOS1500 type isolation RS485 chip can be used in a temperature range of-40 ℃ to 125 ℃, and compared with the traditional optical coupler, the high-voltage isolation type IOS chip has a predictable switch specification and higher noise resistance.
Of course, besides the IOS1500 type isolated RS485 chip, the isolated RS485 chip 1 may also be of other types, and the embodiment of the present invention is not limited herein.
The utility model also provides an electric energy meter, include as RS485 communication system in the aforementioned embodiment.
To the utility model discloses please refer to aforementioned RS485 communication system's embodiment for the introduction of the electric energy meter that the embodiment provided, the embodiment of the utility model provides a no longer give unnecessary details here.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. The utility model provides a RS485 communication system, is applied to the electric energy meter, its characterized in that includes:
the isolation RS485 chip is respectively connected with the external processor and the power supply, and is used for converting TTL level signals sent by the external processor into differential signals and then sending the differential signals out through the interface circuit, converting the differential signals received through the interface circuit into TTL level signals and then sending the TTL level signals to the external processor, and is also used for isolating current flowing from the interface circuit to the external processor;
the interface circuit;
and the first power supply is used for supplying power to the isolated RS485 chip.
2. The RS485 communication system of claim 1, wherein the interface circuit comprises a pull-up resistor, a pull-down resistor, a second power supply, a protection circuit and a connection terminal;
the pull-up resistor is respectively connected with the first differential signal output end of the isolated RS485 chip and the second power supply and is used for clamping the differential signal output by the first differential signal output end at a high level;
the first end of the pull-down resistor is connected with the second differential signal output end of the isolated RS485 chip, and the second end of the pull-down resistor is grounded with the first differential signal output end of the isolated RS485 chip and is used for clamping the differential signal output by the second differential signal output end at a low level;
the protection circuit is respectively connected with the first differential signal output end, the second differential signal output end and the wiring terminal of the isolation type RS485 chip and is used for absorbing external strong electricity to protect the isolation type RS485 chip.
3. The RS485 communication system according to claim 2, wherein the protection circuit is an inrush current absorbing device for absorbing an external inrush current;
the first end of the surge current absorption device is connected with the first differential signal output end and the wiring terminal respectively, and the second end of the surge current absorption device is connected with the second differential signal output end and the wiring terminal respectively.
4. The RS485 communication system of claim 3, wherein the surge current absorbing device is a bidirectional transient suppression (TVS) diode.
5. The RS485 communication system according to claim 3, wherein the protection circuit further comprises a first voltage divider resistor and/or a second voltage divider resistor;
a first end of the first voltage-dividing resistor is connected with a first end of the surge current absorption device and the first differential signal output end respectively, and a second end of the first voltage-dividing resistor is connected with the wiring terminal;
the first end of the second voltage-dividing resistor is connected with the second end of the surge current absorption device and the second differential signal output end respectively, and the second end of the second voltage-dividing resistor is connected with the wiring terminal.
6. The RS485 communication system of claim 5, wherein the first voltage divider resistor and the second voltage divider resistor are both thermistors.
7. The RS485 communication system of claim 1, wherein the first power supply is a two-way isolated power supply.
8. The RS485 communication system according to claim 1, further comprising:
the prompter is connected with the isolated RS485 chip;
the isolated RS485 chip is further configured to control the prompter to prompt that the signal conversion is being performed while performing the signal conversion.
9. The RS485 communication system according to any of claims 1 to 8, wherein the isolated RS485 chip is an IOS1500 type isolated RS485 chip.
10. An electric energy meter, characterized by comprising an RS485 communication system according to any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920638351.3U CN210015164U (en) | 2019-05-06 | 2019-05-06 | Electric energy meter and RS485 communication system thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920638351.3U CN210015164U (en) | 2019-05-06 | 2019-05-06 | Electric energy meter and RS485 communication system thereof |
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| CN210015164U true CN210015164U (en) | 2020-02-04 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111404504A (en) * | 2020-06-03 | 2020-07-10 | 广州天嵌计算机科技有限公司 | RS485 bus differential signal amplifier |
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2019
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111404504A (en) * | 2020-06-03 | 2020-07-10 | 广州天嵌计算机科技有限公司 | RS485 bus differential signal amplifier |
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