CN102508508A - Programmable power circuit of meter bus slave - Google Patents
Programmable power circuit of meter bus slave Download PDFInfo
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- CN102508508A CN102508508A CN2011103736850A CN201110373685A CN102508508A CN 102508508 A CN102508508 A CN 102508508A CN 2011103736850 A CN2011103736850 A CN 2011103736850A CN 201110373685 A CN201110373685 A CN 201110373685A CN 102508508 A CN102508508 A CN 102508508A
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Abstract
The invention relates to a power circuit of a meter bus slave, belonging to the technical field of apparatus meters. The programmable power circuit of the meter bus slave consists of a program-controlled reference voltage generating circuit and an emitter follower, wherein the program-controlled reference voltage generating circuit consists of resistors, two voltage-stabilizing diodes, a reinforced NMOS (n-channel metal oxide semiconductor) tube and a singlechip MCU (micro control unit); a resistor R1 is serially connected with the two voltage-stabilizing diodes; the reinforced NMOS tube which is connected with one voltage-stabilizing diode in parallel is connected with a grid electrode of an NMOS tube VM through an I/O (input/output) port of the singlechip MCU; a resistor R2 is connected between the I/O port of the singlechip MCU and the grid electrode of the NMOS tube VM; a resistor R3 is connected between the I/O port of the singlechip MCU and a positive power supply; the emitter follower comprises two dynatrons V1 and V2 which are connected in a Darlington way; collector electrodes of the two dynatrons V1 and V2 are connected with a high voltage end of the meter bus; emitter electrodes of the dynatrons are connected on a slave load RL; and a substrate of the emitter follower formed by the two dynatrons is connected with the output of the program-controlled reference voltage generating circuit.
Description
Technical field
The present invention relates to a kind of power circuit of meter bus slave computer, belong to the technology of instrument and meter field.
Background technology
One Chinese patent application numbers 200910218395.1 discloses a kind of " low power consumption power supply circuit of meter bus slave computer "; Constitute by high a constant voltage power supply circuit and a low-pass filter circuit withstand voltage, low quiescent current; Described constant voltage power supply circuit is as emitter follower by two triodes that are connected into the Darlington form; The base stage of this emitter follower is connected on the normal voltage by the voltage reference generation; From voltage that output resistance is very low of emitter output, thereby constitute constant pressure source; Described low-pass filter circuit is formed by resistance and a capacitances in series of a low resistance; The emitter of described emitter follower is connected with the resistance of low-pass filter circuit.
Meter bus (Meter-Bus is called for short M-Bus) is a kind of novel serial bus standard, is mainly used in the check meter networking of network of consumption measurement instruments such as water meter, gas meter and thermal meter.Because meter bus has advantages such as networking is convenient, antijamming capability with low cost is strong; Become at present the European standard of 2 line buses; Consume the measurement instrument field at home and abroad, obtained widespread use in the long-distance meter-reading system like water meter, ammeter and gas meter.The principal feature of meter bus is only to use two non-polar leads simultaneously as the data line of supply lines and transmitting serial data, and each end device all is connected in parallel on these two lines, distinguishes through the different address sign indicating number between different nodes on the bus.
Different according to institute's role in the meter bus communication, the node of meter bus network can be divided into two kinds of main frame and slaves.Main frame is the supplier of power supply and the promoter of communication; It provides the supply voltage of 24V-42V through two transmission lines all slaves on bus; And call out the slave hope communication with it through the method for the address of broadcasting slave on bus; Often have only a main frame in the meter bus network, each constantly and host communication also have only a slave.Selected and slave host communication are in " state of activation ", and in the network other all do not have selected slave to be in " dormant state ".Owing to have only two transmission lines on the bus, this two transmission lines also need be born the task of communication between the host and slave processors except will accomplishing the task for the slave power supply, and communication signal is modulated on these two power leads.
Main frame and slave all are made up of power circuit and SCM system, and the slave power circuit obtains working power from the meter bus of 2 line systems, and the slave SCM system " is replied " calling of main frame under the guiding of main frame.On the one hand, often have the multi-section slave in the meter bus network, but because main frame provides the limited in one's ability of electric current, the total amount of the slave in the network is restricted.On the other hand, account for the overwhelming majority owing to be in the slave of dormant state in the whole network, the power consumption that reduces slave under the dormant state will improve the quantity and the overall power consumption that reduces total system of slave on the bus effectively.
The photo-electronic directly reading technology is an important technology that consumes in the remote meter-reading function of measurement instrument field.The binary bar code bar that this technology is printed on the reading character wheel of original mechanical formula measurement instrument and survey measurements is corresponding; Meter bus slave computer is read these binary bar codes corresponding with reading through photoelectric technology; Also just read the measurement result of mechanical type measurement instrument; Slave is issued main frame with the result through meter bus again, thereby realizes remote automatic meter reading.Wherein, Through the photoelectric technology reading is the emphasis and the difficult point of technology: the single-chip microcomputer in the slave is launched infrared light through its I/O mouth control light emitting diode to bar code on one side; Receive the infrared light that reflects on one side, and judge the situation of binary bar code according to reflection strength.In this process, the infrared light intensity of emission is big more, and the infrared light that receives is also strong more, judges that the accuracy of scale-of-two code-bar is also just high more.The I/O mouth of single-chip microcomputer has such characteristic: supply voltage high more (certainly need within the WV that single-chip microcomputer allows), the ability of single-chip processor i/o mouth output current is also just strong more.That is to say that supply voltage is high more, the drive current that single-chip processor i/o can offer the infraluminescence pipe is also just big more, also just can obtain higher infrared electro accuracy of reading rate.
To sum up, have such contradiction in the existing meter bus slave computer circuit design: the slave that is in dormant state in the network in a large number need use the low supply voltage of trying one's best, and to reduce the power consumption of every dormancy slave, reaches the purpose that improves slave total amount in the network; By the slave that main frame is chosen and activated, then hope to obtain higher supply voltage, to satisfy the requirement of work such as photoelectric reading.Because conventional art can't be realized the switching of meter bus slave computer supply voltage, the deviser can only use compromise method to confirm the meter bus slave computer supply voltage---select one can guarantee the slave operate as normal that is activated, the low supply voltage of trying one's best again.And at present popular photoelectric direct-reading meter bus slave computer, the height of supply voltage often is related to the height of the accuracy of reading, and this compromise selection must cause the decline of slave total amount and infrared electro accuracy of reading rate in the network.
Summary of the invention
The object of the invention is intended to overcome the deficiency of prior art, and a kind of program-controlled meter bus slave computer power circuit through program control its supply voltage of single-chip microcomputer in the meter bus slave computer is provided.
Program-controlled meter bus slave computer power circuit of the present invention is made up of programme controlled reference voltage generating circuit and emitter follower; Described programme controlled reference voltage generating circuit is to be made up of resistance, two voltage stabilizing diodes, enhancement mode NMOS pipe and single-chip microprocessor MCU; Resistance R 1 is connected with two voltage stabilizing diodes; Link to each other through the I/O mouth of single-chip microprocessor MCU and the grid of NMOS pipe VM with the enhancement mode NMOS pipe of one of above-mentioned voltage stabilizing diode parallel connection; I/O mouth and NMOS that R2 is connected single-chip microprocessor MCU manage between the grid of VM, and R3 is connected between the I/O mouth and positive supply of single-chip microprocessor MCU; Described emitter follower is two the triode V1, the V2 that are connected into the Darlington form, and the collector of two triode V1, V2 connects the high voltage end of meter bus, and the emitter of triode is connected on the slave load RL; The base stage of the emitter follower of two triode formations links to each other with the output of the reference voltage generating circuit of said procedure control.
" do not chosen ", be in the single-chip microcomputer in the slave of dormant state by main frame in the meter bus network, the control reference voltage circuit produces lower reference voltage; " chosen ", be in single-chip microcomputer in the slave of state of activation then controls reference voltage circuit and produces higher reference voltage by main frame.This power circuit is the slave that is in dormant state, provides to keep the supply voltage of monitoring host command and bus state; Also, sufficiently high WV is provided, to guarantee the accuracy of photoelectric direct-reading table reading for being in the slave of state of activation.The effect of emitter-follower output circuit can also make the supply voltage of its output follow the variation of reference voltage except amplified current.
Existing meter bus slave computer power supply generally has constant current source and two kinds of implementations of constant pressure source:
Be in dormancy under the constant current source mode and not only use identical voltage, also consume identical electric current with slave under the state of activation.Those are in the slave of dormant state, must fall the part electric current through constant-current source circuit " waste ", equate to guarantee its consumed current and the slave that is in state of activation.Just mean also constant-current source circuit all consumes identical and maximum electric currents no matter export which kind of voltage, programmable power supply voltage is to not effect of sort circuit.
The slave power supply of constant pressure source mode can be exported different electric currents as required, to reach the purpose that reduces the current sinking under the dormant state.But the shortcoming of prior art is the voltage that can't change power supply output, causes slave must use identical voltage in dormant state with state of activation.In order to guarantee the slave operate as normal under the state of activation, supply voltage can not be too low; Because supply voltage is higher, the slave under the dormant state then can't reach power saving effect preferably.
As long as the single-chip microcomputer that the lower supply voltage that power circuit produces among the present invention can be kept in the slave is monitored the instruction that main frame sends in the meter bus; The higher supply voltage that produces is then wanted to satisfy the requirement of photo-electronic directly reading circuit to the reading accuracy.Compare with the prior art solution, adopt program-controlled supply voltage, reduced supply voltage and the current drain that is in the slave under the dormant state on the one hand, enlarged the capacity of meter bus network; Improve the supply voltage of state of activation slave on the other hand, thereby improved the accuracy rate of slave reading.Be particularly suitable for the meter bus system of low-power consumption such as photoelectric direct-reading water meter, gas meter, have excellent generalization values.
Description of drawings
Fig. 1 is a meter bus slave computer theory diagram of the present invention.
Fig. 2 is a circuit diagram of the present invention.
Among Fig. 2, frame of broken lines A is programme controlled reference voltage generating circuit, and frame of broken lines B is an emitter follower circuit.
Embodiment
Provide concrete embodiment that the present invention is done further explanation below, but it is not used in restriction the present invention.
The on off state that single-chip microprocessor MCU is managed through the NMOS in the programmed control voltage reference: when this slave is in dormant state; The relevant I/O mouth output of SCM program control high level; The grid of the NMOS pipe VM that links to each other with the I/O mouth through R2 is pulled to high level, and VM is switched on.The voltage stabilizing diode UREF2 of parallel connection is by short circuit with it, and the electric potential difference at UREF2 two ends is 0.The reference voltage that the REF point obtains only is that electric current punctures the voltage that obtains behind the UREF1, and voltage is lower.After the instruction activation that this slave is sent by main frame, single-chip microcomputer will be from relevant I/O mouth output low level, and the grid of VM is pulled to low level through R2, and VM is ended.To have breakdown current to flow through on the voltage stabilizing diode UREF2 of parallel connection with it, the electric potential difference at its two ends is the voltage breakdown of UREF2.The reference voltage that the REF point obtains will be that electric current punctures the electric potential difference sum that obtains behind UREF1 and the UREF2, and voltage is higher.
Triode V1 or V2 constitute emitter follower and play the reference voltage of following the output of REF point, and the effect of amplified current.The emitter of triode will be followed the change in voltage of base stage and changed; Under the programmed control of reference voltage that the REF that is connected with base stage is ordered at single-chip microcomputer; When changing according to the activation instruction of meter bus main frame, the supply voltage of emitter output also will change thereupon.Variation has also just taken place in the supply voltage that the slave functional circuit obtains thereupon.Triode has reduced the output impedance of whole power circuit to the amplification of base current, has improved output current.
Fig. 2 is an instantiation of the slave power circuit addressed of the present invention.Two lines of meter bus are the socket input of MBUS_IN from label; Circuit among the square frame A realizes producing the function of program-controlled voltage benchmark VREF: resistance R 1 and parallel connection type bandgap reference voltage chip (being equivalent to stabilivolt) UREF1 and UREF2 (model is LM4040-4.1 and LM4040-2.5) series connection, the pressure drop that will produce 4.1V and 2.5V after they are breakdown.UREF2 and enhancement mode N-channel MOS pipe VM (model is FDN359) parallel connection, when the single-chip processor i/o mouth is exported high level under programmed control, the VM conducting, the conducting resistance of FDN359 is merely 60m Ω, and UREF2 is by short circuit, and program-controlled voltage benchmark VREF is merely 4.1V; When the single-chip processor i/o mouth under programmed control during output low level, VM ends, UREF2 is breakdown, program-controlled voltage benchmark VREF is merely 6.6V.Circuit among the square frame B is to unite the emitter follower that constitutes by two triodes that are connected into the Darlington form.The emitter follower of Darlington form is compared the emitter follower that single triode constitutes, and has the big advantage of current gain.If two triodes are all selected 2N5551 for use, then total currentgain can reach more than 5000, and voltage reference circuit only need provide very little electric current can guarantee the needs of slave functional circuit for the base stage of this emitter follower.The Darlington transistor base stage is about 1.4V to the pressure drop of emitter-base bandgap grading, and (promptly 2 * 0.7V), the high voltage of whole like this power circuit output is about 5.2V (being 6.6V-1.4V), and low-voltage is about 2.7V (being 4.1V-1.4V).The single-chip microprocessor MCU model that slave adopted is PIC16F883, and its supply voltage scope is 2.0-5.5V, meets design requirement.
The VCC termination power of single-chip microprocessor MCU, GND holds ground connection.
The effect of resistance R 1 is the electric current that voltage stabilizing diode UREF1 and UREF2 are flow through in restriction among Fig. 1, no matter R1 must guarantee that UREF1 and UREF2 can obtain enough to keep the electric current of puncture under output LOW voltage or the high-tension situation, the value of R1 is 75K Ω.The effect of R2 and R3 is during the single-chip microcomputer electrification reset, and the grid of NMOS is implemented to draw.When the electrification reset stage, the single-chip processor i/o mouth was in high-impedance state, grid obtained high level, the NMOS conducting, and whole power circuit will obtain stable low-voltage, and the value of R2 and R3 is respectively 10K Ω.Capacitor C 1 is used for the output of stability program control reference voltage generating circuit, is connected between the output and ground of voltage stabilizing diode.The load that on behalf of the meter bus slave computer circuit, RL produce, it and single-chip microcomputer are connected in parallel between the power supply and ground that emitter follower produces.
Embodiment 1 (based on the sub-district water meter kilowatt meter reading-out system of meter bus):
The long-range water meter kilowatt meter reading-out system of photoelectric direct-reading is adopted in certain sub-district, reads in the sub-district water consumption at family surplus in the of 500 through meter bus.In this meter bus system, only property management office has one to be used for reading of data meter bus main frame in the sub-district, and the photoelectric direct-reading gauge outfit as meter bus slave computer only has been installed in the water user family.
The constant voltage reference UREF1 that the slave power supply uses adopts the band-gap reference chip LM4040-4.1 of low working current, and UREF2 adopts LM4040-2.5, and their voltage breakdown is respectively 4.1V and 2.5V.Because LM4040 only needs 60uA to get final product steady operation.Current-limiting resistance R1 gets 75K Ω, and the assurance system also can steady operation between the meter bus communication period.In order to reduce the quiescent current of constant pressure source, V1, V2 are connected into the Darlington form, constitute emitter follower, and V1, V2 have enough withstand voltage low-power transistor 2N5551.The supply voltage that this moment, the slave power supply was exported under dormant state is 2.7V, and the voltage of under state of activation, exporting is 5.2V.Employed single-chip microcomputer (MCU) is the low-power consumption of Microchip company, the PIC16F883 of wide operating voltage range, it can be between 2.0V～5.5V operate as normal.Under identical 2MHz dominant frequency, only about 500uA, the working current during 5.2V will reach about 1500uA the working current of PIC16F883 during supply voltage 2.7V; The fan-out capability of the I/O mouth of PIC16F883 is 2-3mA during supply voltage 2.7V, and its fan-out capability can reach more than the 30mA during 5.2V.
If the photo-electronic directly reading water meter adopts fixing 5.2V as supply voltage, then the working current of (Yi Yitai is in state of activation, and 499 are in the dormant state meter) will reach 1500uA * 499+30mA=778.5mA during the operate as normal of system.In each load capacity to twisted-pair feeder 300mA, this system needs 3 pairs of twisted-pair feeders at least during wiring.If the photo-electronic directly reading table adopts fixing 2.7V as supply voltage; Though working current is merely 500uA * 499+3mA=252.5mA; Only need a pair of twisted-pair feeder; But owing to can offer the electric current too little (only 3mA) of photo-electronic directly reading table, the reading accuracy is merely 50% to be owned, and can not satisfy the requirement of system's correct rate.
If adopt the disclosed variable voltage power supply of the application's book, then 499 slaves that are under the dormant state are in the low voltage operating state of 2.7V, only consume the 500uA electric current.And 1 slave that is activated is operated in the high-voltage state of 5.2V, can the 30mA electric current that need be provided for the photo-electronic directly reading system, to guarantee the reading accuracy more than 99.9%.The working current of whole kilowatt meter reading-out system consumption equals: 500uA * 499+30mA=279.5mA only needs a pair of twisted-pair feeder.
Practical application shows that method of the present invention has effectively reduced the power consumption of meter bus system, has improved the capacity of system, has reduced the system maintenance cost.
Embodiment 2 (based on sub-district gas meter, the ammeter ' s reading meter system of meter bus):
The analysis that the meter bus overall electric current consumes in this example is identical with embodiment 1, no longer repeats here.
Claims (2)
1. program-controlled meter bus slave computer power circuit; It is characterized in that constituting by programme controlled reference voltage generating circuit and emitter follower; Described programme controlled reference voltage generating circuit is to be made up of resistance, two voltage stabilizing diodes, enhancement mode NMOS pipe and single-chip microprocessor MCU; Resistance R 1 is connected with two voltage stabilizing diodes; Link to each other through the I/O mouth of single-chip microprocessor MCU and the grid of NMOS pipe VM with the enhancement mode NMOS pipe of one of above-mentioned voltage stabilizing diode parallel connection, I/O mouth and NMOS that R2 is connected single-chip microprocessor MCU manage between the grid of VM, and R3 is connected between the I/O mouth and positive supply of single-chip microprocessor MCU; Described emitter follower is two the triode V1, the V2 that are connected into the Darlington form, and the collector of two triode V1, V2 connects the high voltage end of meter bus, and the emitter of triode is connected on the slave load RL; The base stage of the emitter follower of two triode formations links to each other with the output of the reference voltage generating circuit of said procedure control.
2. program-controlled meter bus slave computer power circuit as claimed in claim 1 is characterized in that capacitor C 1 is connected between the output and ground of voltage stabilizing diode.
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| CN2011103736850A CN102508508A (en) | 2011-11-22 | 2011-11-22 | Programmable power circuit of meter bus slave |
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| CN2011103736850A CN102508508A (en) | 2011-11-22 | 2011-11-22 | Programmable power circuit of meter bus slave |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105976595A (en) * | 2016-07-19 | 2016-09-28 | 天津市炳华节能技术有限公司 | Implementing method of low-power-consumption M-BUS main station |
| CN108302239A (en) * | 2017-10-31 | 2018-07-20 | 瑞纳智能设备股份有限公司 | A kind of MBUS control circuits and its control method for thermostat valve |
| CN110311845A (en) * | 2019-07-27 | 2019-10-08 | 深圳市骏普科技开发有限公司 | A kind of bus-powered method of battery-operated type M-BUS |
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| CN101776931A (en) * | 2009-12-18 | 2010-07-14 | 云南大学 | Low power consumption power supply circuit of meter bus slave computer |
| CN201656779U (en) * | 2010-04-27 | 2010-11-24 | 珠海格力电器股份有限公司 | Low power consumption standby circuit and electric appliance |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105976595A (en) * | 2016-07-19 | 2016-09-28 | 天津市炳华节能技术有限公司 | Implementing method of low-power-consumption M-BUS main station |
| CN108302239A (en) * | 2017-10-31 | 2018-07-20 | 瑞纳智能设备股份有限公司 | A kind of MBUS control circuits and its control method for thermostat valve |
| CN110311845A (en) * | 2019-07-27 | 2019-10-08 | 深圳市骏普科技开发有限公司 | A kind of bus-powered method of battery-operated type M-BUS |
| CN110311845B (en) * | 2019-07-27 | 2021-10-08 | 深圳市骏普科技开发有限公司 | Battery-powered M-BUS (Meter-BUS) BUS power supply method |
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Application publication date: 20120620 |