CN101666675B - Weighing indicator - Google Patents
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- CN101666675B CN101666675B CN2008100423960A CN200810042396A CN101666675B CN 101666675 B CN101666675 B CN 101666675B CN 2008100423960 A CN2008100423960 A CN 2008100423960A CN 200810042396 A CN200810042396 A CN 200810042396A CN 101666675 B CN101666675 B CN 101666675B
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Abstract
The invention discloses a weighing indicator, which is characterized in that an AD conversion circuit comprises an analog-to-digital conversion circuit connected with a weighing sensor; an output end of the weighing sensor is connected with an analog input end of the analog-to-digital conversion circuit; the analog-to-digital conversion circuit is connected with a first bus; the weighing sensor is connected with an alternating current excitation circuit; the alternating current excitation circuit is connected with an alternating current excitation driving circuit; the alternating current excitation driving circuit is connected with the analog-to-digital conversion circuit; the alternating current excitation driving circuit is connected with an overcurrent protection circuit; the overcurrent protection circuit is connected with a restart circuit; the restart circuit is connected with the first bus; and the overcurrent protection circuit is connected with the alternating current excitation circuit. The weighing indicator has the advantages of adopting the overcurrent protection circuit to perform sampling treatment on the output of the alternating current excitation circuit and then feeding back a result of the sampling treatment to the alternating current excitation driving circuit, thereby realizing the reliable protection on an alternating current excitation power supply of the sensor and avoiding the damage of instruments caused by external fault.
Description
Technical field
The present invention relates to circuit field, be specifically related to a kind of Weighing indicator.
Background technology
Weighing indicator in the market partly is made up of display of LOAD CELLS, electronic amplification circuit, analog to digital converter, data processing circuit and demonstration weight etc.; during the sensor wiring because the influence of thermoelectric force; can cause the instability at zero point; thereby make measuring accuracy not high; transducer excitation voltage does not have overcurrent protection, poor reliability.Existing in addition Weighing indicator also exists small product size big, transmits data with parallel bus between each module, makes the complex circuit of complete machine, shortcomings such as cost height, and can not show Chinese character, man-machine interface is poor.
Summary of the invention
One object of the present invention is to provide a kind of more accurate and reliable Weighing indicator, can overcome above shortcoming.
To achieve these goals; technical scheme of the present invention is as follows: a kind of Weighing indicator; comprise single-chip microcomputer; LOAD CELLS is connected with A/D convertor circuit; A/D convertor circuit is connected with single-chip microcomputer by first bus; single-chip microcomputer is connected with character library by first bus; single-chip microcomputer also is connected with storage unit by second bus; single-chip microcomputer is connected with display by display interface device; single-chip microcomputer is connected with keyboard by keyboard interface; single-chip microcomputer also is connected with power module; it is characterized in that this A/D convertor circuit comprises the analog to digital conversion circuit that is connected with LOAD CELLS; the output terminal of LOAD CELLS is connected with the analog input end of this analog to digital conversion circuit; this analog to digital conversion circuit is connected with first bus; LOAD CELLS is connected with ac driven circuit; ac driven circuit is connected with ac-excited driving circuit; this ac-excited driving circuit is connected with analog to digital conversion circuit; this ac-excited driving circuit is connected with current foldback circuit; this current foldback circuit with restart circuit and be connected; restart circuit and be connected with single-chip microcomputer IO mouth line, current foldback circuit is connected with ac driven circuit.
Single-chip microcomputer also is connected with the built-in thermal printer of instrument by the thermal printer interface.Single-chip microcomputer also is connected with communication interface with the external printer interface, is convenient to be connected with external printer, data can be carried out the strange land by communication interface simultaneously and transmit.
The invention has the advantages that and adopt current foldback circuit that the output of ac driven circuit is carried out feeding back to ac-excited driving circuit after the sampling processing; thereby realize the reliably protecting to the ac-excited power supply of sensor, the instrument of having avoided causing because of external fault is damaged.Restarting circuit provides externally under the situation of circuit transient fault, and the possibility that system resumes work automatically makes system more stable.Power supply switch circuit can cut off direct supply fully when Alternating Current Power Supply, avoided the consumption of direct supply.When direct current supply, the feedback circuit of ac-dc converter circuit does not have electric current to pass through, and has avoided the additive decrementation of direct supply, has prolonged the working time of direct supply.Adopted ac-excited LOAD CELLS bridge power supply and corresponding AD converter, eliminated the influence of the thermoelectric force of sensor wiring, zero point is highly stable.Adopted the ARM7 series monolithic as CPU (central processing unit), computing velocity is fast, and interface function is powerful.Adopt the mixed display mode of character graphics display module and LED charactron, operation intuitive and convenient, man-machine interface close friend.
Description of drawings
Fig. 1 is a circuit block diagram of the present invention
Fig. 2 is the circuit block diagram of A/D convertor circuit
Fig. 3 is the circuit diagram of A/D convertor circuit
Fig. 4 is the circuit block diagram of power supply switch circuit
Fig. 5 is the circuit diagram of power supply switch circuit
Fig. 6 is the circuit block diagram of display
Fig. 7 is the circuit diagram of display
Fig. 8 is the circuit diagram of keyboard interface circuit
Embodiment
Below in conjunction with drawings and Examples the present invention is elaborated.
A kind of Weighing indicator, comprise single-chip microcomputer 3, LOAD CELLS 1 is connected with A/D convertor circuit 2, and A/D convertor circuit 2 is that spi bus 18 is connected with single-chip microcomputer 3 by first bus, single-chip microcomputer 3 is connected with character library 4 by first bus 18, and single-chip microcomputer 3 is I by second bus also
2 C bus 19 is connected with storage unit 7; single-chip microcomputer 3 is connected with display 8 by display interface device 9; single-chip microcomputer 3 is connected with keyboard 11 by keyboard interface 10; single-chip microcomputer 3 also is connected with power module 20; it is characterized in that this A/D convertor circuit 2 comprises the analog to digital conversion circuit 22 that is connected with LOAD CELLS 1; the output terminal of LOAD CELLS 1 is connected with the analog input end of this analog to digital conversion circuit 22; this analog to digital conversion circuit 22 is connected with first bus 18; LOAD CELLS 1 is connected with ac driven circuit 23; ac driven circuit 23 is connected with ac-excited driving circuit 24; this ac-excited driving circuit 24 is connected with analog to digital conversion circuit 22; this ac-excited driving circuit 24 is connected with current foldback circuit 25; this current foldback circuit 25 with restart circuit 26 and be connected; restart circuit 26 and be connected with the IO mouth line of single-chip microcomputer 3, current foldback circuit 25 is connected with ac driven circuit 23.In the present invention, storage unit 7 is EEPROM.
As shown in Figure 3; ac driven circuit 23 is: the source electrode of the first field effect transistor Q5 is connected with power supply; the drain electrode of the first field effect transistor Q5 is connected with the drain electrode of the second field effect transistor Q6; the source electrode of the second field effect transistor Q6 and the input end of current foldback circuit 25 are that the end of sampling resistor R35 is connected; the source electrode of the 3rd field effect transistor Q4 is connected with power supply; the drain electrode of the 3rd field effect transistor Q4 is connected with the drain electrode of the 4th field effect transistor Q3; the source electrode of the 4th field effect transistor and the input end of current foldback circuit 25 are that the end of sampling resistor R35 is connected; the junction of the first field effect transistor Q5 and the second field effect transistor Q6 is an output terminal of excitation power supply; be connected with an input end of LOAD CELLS 1; the junction of the 3rd field effect transistor Q4 and the 4th field effect transistor Q3 is another output terminal of excitation power supply; be connected with another input end of LOAD CELLS 1, the grid of these four field effect transistor is connected with ac-excited driving circuit 24.
The circuit of ac-excited driving circuit 24 is: the input end of the first Sheffer stroke gate U7A is connected with the ACX end of analog to digital conversion circuit 22; another input end of the first Sheffer stroke gate U7A is connected with the output terminal of current foldback circuit 25; the output terminal of the first Sheffer stroke gate U7A is connected with the control end of the first field effect transistor Q5; the second Sheffer stroke gate U7B and the first Sheffer stroke gate U7A are connected in parallel; the input end of the 3rd Sheffer stroke gate U7C is connected with the ACX end of analog to digital conversion circuit 2; another input end of the 3rd Sheffer stroke gate U7C is connected with the output terminal of current foldback circuit 25; the output terminal of the 3rd Sheffer stroke gate U7C is connected with the grid of the 3rd field effect transistor Q4; the 4th Sheffer stroke gate U7D and the 3rd Sheffer stroke gate U7C are connected in parallel; the grid of the 4th field effect transistor Q3 is connected with the ACX end of analog to digital conversion circuit 2, and the grid of the second field effect transistor Q6 is connected with the ACX end of analog to digital conversion circuit 2.In this embodiment, the first Sheffer stroke gate U7A is in parallel with the second Sheffer stroke gate U7B to improve driving force, and the first Sheffer stroke gate U7C is in parallel with the second Sheffer stroke gate U7D to improve driving force.
The circuit of current foldback circuit 25 is: the input end of this current foldback circuit 25 is the end of sampling resistor R35; the other end ground connection of sampling resistor R35; the input end of this current foldback circuit 25 also is connected with the positive input terminal of the first comparer U5B by resistance R 36; the positive input terminal of the first comparer U5B is also by capacitor C 36 ground connection; the negative input end of the first comparer U5B connects power supply by resistance R 44; the negative input end of the first comparer U5B is simultaneously by resistance R 45 ground connection; the negative input end of the first comparer U5B also connects power supply by capacitor C 34 and the resistance R 43 that is connected in series; be connected with feedback resistance R41 between the positive input terminal of the output terminal of the first comparer U5B and the first comparer U5B; the output terminal of the first comparer U5B also is connected with the negative input end of the 4 two comparer U5A; the positive input terminal of the second comparer U5A connects power supply by resistance R 33; the positive input terminal of the second comparer U5A is also by resistance R 40 ground connection; the output terminal of the second comparer U5A connects power supply by the 8th resistance R 34; the output terminal of the first comparer U5B also connects power supply by the 9th resistance R 37, and the output terminal of the second comparer U5A is the output terminal of this current foldback circuit 25.
The circuit that restarts circuit 26 is: the Restart Signal end CAL-E of first bus 18 is connected with an end of capacitor C 37, the other end of capacitor C 37 is connected with the positive pole of diode D13, the minus earth of diode D13, the other end of capacitor C 37 also are connected with the positive input terminal of the first comparer U5B by resistance R 46.
Analog to digital conversion circuit 22 makes the first field effect transistor Q5, the 4th field effect transistor Q3 of ac driven circuit 23 or the 3rd field effect transistor Q4, the second field effect transistor Q6 timesharing conducting by ac-excited driving circuit 24, forms the transducer excitation voltage of ac square wave form; The sensor excitation electric current flows through the sampling resistor R35 of current foldback circuit 25.Circuit powers on when starting working, because capacitor C 34 and C36 make the output terminal of the comparer U5B that wins remain on low level, the output terminal of the second comparer U5A remains on high level, and the output of Sheffer stroke gate U7A～U7D is at this moment worked by normal condition by the control of analog to digital conversion circuit 22.When sensor excitation circuit overcurrent or when short trouble occurring; the voltage drop at the sampling resistor R35 two ends of current foldback circuit 25 surpasses the partial pressure value of resistance R 44 and resistance R 45; first comparer U5B upset, high level appears in the output terminal of U5B, makes the second comparer U5A overturn.The output terminal of U5A is a low level, make the output terminal of four Sheffer stroke gate U7A～U7D of ac-excited driving circuit 24 be locked in high level, make the 3rd field effect transistor Q4 and Q5 in the ac driven circuit 23 end immediately, cut off the excitation power supply of LOAD CELLS 1, prevented each device failure in the circuit.The high level that the first comparer U5B output terminal occurs makes comparer maintain rollover states by the positive input terminal that feedback resistance R41 is added in the first comparer U5B always.
Under the control of single-chip microcomputer; Restart Signal end CAL-E adds a negative pulse voltage; the positive input terminal that the capacitor C 37 by restarting circuit 26 and first resistance R 46 are coupled to the first comparer U5B of current foldback circuit 25; can make the first comparer U5B recover normal condition, diode D13 provides discharge channel for capacitor C 37.Can set single-chip microcomputer in single-chip microcomputer and restart number of times, the system that makes maintains guard mode stablizing under the state of fault.
A/D convertor circuit 2 adopts current foldback circuit that the output of ac driven circuit is carried out feeding back to ac-excited driving circuit after the sampling processing, thereby realizes the reliably protecting to the ac-excited power supply of sensor, and the instrument of having avoided causing because of external fault is damaged.Restarting circuit provides externally under the situation of circuit transient fault, and the possibility that system resumes work automatically makes system more stable.
As can be seen from Figure 4, power module comprises AC power interface 15, direct supply interface 17, and AC power interface 15 is connected with single-chip microcomputer 3 by power supply switch circuit 16 with direct supply interface 17.Wherein as shown in Figure 4, power supply switch circuit comprises voltage stabilizer 42, this direct supply interface 17 is connected with the first input end of voltage stabilizer 42, the output terminal of voltage stabilizer 42 is connected with output end of pressure-stabilizing 48, AC power interface 15 is connected with the input end of ac-dc converter circuit 44, first output terminal of ac-dc converter circuit 44 is connected with output end of pressure-stabilizing 48, second output terminal of ac-dc converter circuit 44 is connected with the input end of AC power testing circuit 45, the output terminal of AC power testing circuit 45 is connected with the first input end of direct supply control circuit 46, second input end of direct supply control circuit 46 is connected with single-chip microcomputer, and the output terminal of direct supply control circuit 46 is connected with the control end of voltage stabilizer 42.The automatic switchover of AC power interface 15 and direct supply interface 17 has realized civil power and battery powered automatic switchover, is user-friendly to, and has prolonged the service time of reserve battery.Output end of pressure-stabilizing 48 output voltages use for each element of whole Weighing indicator.
As shown in Figure 5, ac-dc converter circuit 44 comprises AC-DC conversion module 49 and feedback module 40, the first input end of AC-DC conversion module 49 is connected with AC power interface 43, the output terminal of this AC-DC conversion module 49 is connected with output end of pressure-stabilizing 48, comprise a transformer B1 in the AC-DC conversion module 49, the secondary output end of transformer B1 is connected with the input end of AC power testing circuit 45, the output terminal of AC power testing circuit 45 is connected with the input end of feedback module 40, and the output terminal of feedback module is connected with second input end of AC-DC conversion module.Wherein AC-DC conversion module 49 and feedback module 40 are prior art, do not repeat them here.Wherein the model of U15 is TL431.
The circuit of AC power testing circuit 45 is: the transformer B1 secondary output end of AC-DC conversion module 49 is connected with the positive pole of the first diode D27, the negative pole of the first diode D27 is connected with an end of capacitor C 77, the other end ground connection of capacitor C 77, the negative pole of the first diode D27 is the output terminal of AC power testing circuit 45, is connected with the AC-ON port of output end of pressure-stabilizing 48.
The circuit of direct supply control circuit 46 is: the negative pole of voltage stabilizing diode D28 is connected with the output terminal of AC power testing circuit 45, the positive pole of voltage stabilizing diode D28 is connected with the base stage of the first triode Q11 by first resistance R 128, the grounded emitter of the first triode Q11, the collector of first utmost point pipe Q11 is connected with the control end of voltage stabilizer 42, the base stage of the first triode Q11 also is connected with an end of second resistance R 129, the other end of second resistance R 129 is connected with the collector of the second triode Q12, the grounded emitter of the second triode Q12, the collector of the second triode Q12 also is connected with the input end of voltage stabilizer 42 by the 5th resistance, the base stage of the second triode Q12 is connected with an end of the 3rd resistance R 125, the other end of the 3rd resistance R 125 is connected with an end of the 4th resistance R 131, the other end of the 4th resistance R 131 is connected with the DC-ON port of single-chip microcomputer 3, the DC-ON port of single-chip microcomputer 3 is by the 5th resistance R 132 ground connection, the base stage of the first triode Q11 also is connected with the positive pole of the second diode D25, the negative pole of the second diode D25 is connected with the ON/OFF port of single-chip microcomputer 3, the output terminal of voltage stabilizer 2 is connected with the base stage of the second triode Q12 with first capacitor C 81 by the 6th resistance R 121, the tie point of the 6th resistance R 121 and first capacitor C 81 also is connected with the positive pole of the 3rd diode D26, and the negative pole of the 3rd diode D26 is connected with the ON/OFF port of single-chip microcomputer 3.
Wherein voltage stabilizer 2 is the direct current supply mu balanced circuit of core for the LDO linear voltage regulator that band turn-offs control, and this technology is a prior art, does not repeat them here.The AC-DC conversion module of ac-dc converter circuit 4 and feedback module are prior art also, do not repeat them here.
The ON/OFF port of single-chip microcomputer 3 is for pressing key control switch power supply signal, and shorted to earth is a switch power supply, and the DC-ON port of single-chip microcomputer 3 is the switching signal of Single-chip Controlling direct supply, and high level is for opening, and low level is for closing.
When using direct current supply, because the AC-ON signal voltage that AC power testing circuit 45 provides is zero, the feedback module of ac-dc converter circuit 44 does not have electric current to pass through, and direct supply does not have extra current drain.During ac power supply, the AC-ON signal of AC power testing circuit 45 output is a high level, makes triode Q11 conducting through the voltage stabilizing diode D28 and the resistance R 128 of direct supply control circuit 46, and voltage stabilizer 42 is turn-offed, and direct supply quits work.
Fig. 6～Fig. 7 shows the circuit block diagram and the circuit diagram of display 8.Display of the present invention adopts LCD lattice module and LED charactron to form two demonstrations, and wherein the LCD module can show Chinese character information, and the LED charactron shows the data of weighing.Display 8 comprises led module 35, LCD module 32, the output terminal of led drive circuit 34 is connected with led module 35 input ends, the input end of led drive circuit 34 is connected with the output terminal of decoding scheme 33, the input end of decoding scheme 33 is connected with display interface device 9, and the input end of LCD module 32 is connected with display interface device 9.The power end of display interface device 9 is connected with the power end of LCD module 32 by stabilized voltage supply 36.As shown in Figure 7, decoding scheme 33 comprise first or the door U5C, the input end of the LCD-WR of display interface device 9 end and LCD-RD end and this first or a U5C is connected, this first or the STB end of the door output terminal of U5C and led drive circuit 34 is connected, the D0 end of display interface device 9 and D1 end are held to hold with CLK with the DIO of led drive circuit 34 respectively and are connected.According to another embodiment of the present invention, the D0 of display interface device 9 end with second or input end be connected, second or the DIO of output terminal and the led drive circuit 34 of door hold and be connected, the D1 of display interface device 9 end is connected with the 3rd or the input end of door, the 3rd or output terminal hold with the CLK of led drive circuit 34 and be connected.
In this scheme, LCD module 32 adopts original circuit, with the gating signal of LCD-CS as module, because in the drive signal sequential of LCD module 32, LCD-WR and LCD-RD can not be low level simultaneously, therefore be the gating signal LED-CS of low level state simultaneously with LCD-WR and LCD-RD, prevent that the signal that drives two modules from interfering with each other as led drive circuit 34.
In Fig. 7, J1 adopts interface socket, and U1 adopts SPX11117M3-3.3, and U4 and U3 adopt 3 charactrons, and U2 adopts CS1694, and U5C adopts 74HCT32.
Fig. 8 is the circuit diagram of keyboard interface.This keyboard interface comprises interface circuit and keyboard matrix, and interface circuit is provided with n root lead-in wire, and every lead-in wire connects invalid ground level or the high level of expression key by resistance respectively, it is characterized in that keyboard matrix comprises a plurality of buttons, and each marking keys is K
Ij, wherein i represents row, j represents row, i=0～n-2, j=1～n-1, i＜j.Wherein an end of the button of i row all is connected in series with i root lead-in wire, and the other end of the button that j is capable all is connected in series with j root lead-in wire.As shown in the figure, the keyboard matrix of these 8 lead-in wires comprises 28 buttons, and each button is represented K
Ij, i=0～6 wherein, j=1～7, i＜j.One end of the 0th row button all is connected with first lead-in wire P0.0, one end of the 1st row button all is connected with second lead-in wire P0.1, one end of the 2nd row button all is connected with the 3rd lead-in wire P0.2, one end of the 3rd row button all is connected with the 4th lead-in wire P0.3, one end of the 4th row button all is connected with the 5th lead-in wire P0.4, one end of the 5th row button all is connected with six wire P0.5, one end of the 6th row button all is connected with the 7th lead-in wire P0.6, one end of the 7th row button is connected with the 8th lead-in wire P0.7, the other end of the 1st row's button is connected with second lead-in wire P0.1, the other end of the 2nd row's button all is connected with the 3rd lead-in wire P0.2, the other end of the 3rd row's button all is connected with the 4th lead-in wire P0.3, the other end of the 4th row's button all is connected with the 5th lead-in wire P0.4, the other end of the 5th row's button all is connected with six wire P0.5, the other end of the 6th row's button all is connected with the 7th lead-in wire P0.6, and the other end of the 7th row's button all is connected with the 8th lead-in wire P0.7.
Single-chip microcomputer uses wherein a lead-in wire as output pin and drive and be significant level successively, makes other lead-in wire be input end simultaneously, and whether the level that detects these lead-in wires again is effective, can judge which button closure.Because arbitrary moment, it is output state that a lead-in wire is only arranged, and can not cause short circuit to damage so can save buffer circuit.Use this method, the n of single-chip microcomputer IO pin can connect the button of n * (n-1)/2 at most.
Weighing indicator is connected with strain gauge load cell (not drawing among the figure) by sensor interface 1.Weighing indicator provides the ac-excited power supply that has overcurrent and short-circuit protection by A/D convertor circuit 2 to LOAD CELLS, the signal voltage that LOAD CELLS output is directly proportional with the product of driving voltage and weight weight.Signal voltage is by being that the A/D convertor circuit 2 of reference voltage converts the digital signal that only is directly proportional with weight to the driving voltage, be input to single-chip microcomputer (CPU) 3 by spi bus 18, single-chip microcomputer 3 calculates real weight by mathematics manipulation, and weight data is by LED and the shared display interface device 9 of LCM module sends into LED and LCM module display assembly 8 shows.Weight data also can pass through I
2C bus 19 is sent into EEPROM data-carrier store 7 and is stored, and can take out in the moment of needs again.Weight data also can print by thermal printer interface 6 and thermal printer 5, or prints by external printer interface 12 and external printer (not drawing among the figure).Weight data can also be connected with host computer or miscellaneous equipment (not drawing among the figure) by communication interface 13, transmission weight data or reception steering order.Single-chip microcomputer 3 is connected with keyboard 11 by keyboard interface 10, and operating personnel are by the work of Keyboard Control weight display.Weight display can use AC network to pass through AC power supplies interface 15 and 14 power supplies of AC-DC change-over circuit, also can use external direct current power supply to pass through 17 power supplies of DC power interface, duplex feeding makes the consumption of the external backup battery of DC interface be reduced to minimum by power supply switch circuit 16 controls of patented technology.
Claims (8)
1. Weighing indicator; comprise single-chip microcomputer; LOAD CELLS is connected with A/D convertor circuit; A/D convertor circuit is connected with single-chip microcomputer by first bus; single-chip microcomputer is connected with character library by first bus; single-chip microcomputer also is connected with storage unit by second bus; single-chip microcomputer is connected with display by display interface device; single-chip microcomputer is connected with keyboard by keyboard interface; single-chip microcomputer also is connected with power module; it is characterized in that this A/D convertor circuit comprises the analog to digital conversion circuit that is connected with LOAD CELLS; the output terminal of LOAD CELLS is connected with the analog input end of this analog to digital conversion circuit; this analog to digital conversion circuit is connected with first bus; LOAD CELLS is connected with ac driven circuit; ac driven circuit is connected with ac-excited driving circuit; this ac-excited driving circuit is connected with analog to digital conversion circuit; this ac-excited driving circuit is connected with current foldback circuit; this current foldback circuit with restart circuit and be connected; restart circuit and be connected with single-chip microcomputer IO mouth line, current foldback circuit is connected with ac driven circuit.
2. Weighing indicator as claimed in claim 1 is characterized in that power module comprises AC power interface, the direct supply interface, and AC power interface is connected with single-chip microcomputer by power supply switch circuit with the direct supply interface.
3. Weighing indicator as claimed in claim 2, it is characterized in that power supply switch circuit comprises voltage stabilizer, this direct supply interface is connected with the first input end of voltage stabilizer, the output terminal of voltage stabilizer is connected with output end of pressure-stabilizing, AC power interface is connected with the input end of ac-dc converter circuit, first output terminal of ac-dc converter circuit is connected with output end of pressure-stabilizing, second output terminal of ac-dc converter circuit is connected with the input end of AC power testing circuit, the output terminal of AC power testing circuit is connected with the first input end of direct supply control circuit, second input end of direct supply control circuit is connected with single-chip microcomputer, and the output terminal of direct supply control circuit is connected with the control end of voltage stabilizer.
4. Weighing indicator as claimed in claim 3, it is characterized in that display comprises led module, the LCD module, the output terminal of led drive circuit is connected with the led module input end, the input end of led drive circuit is connected with the output terminal of decoding scheme, the input end of decoding scheme is connected with display interface device, and the input end of LCD module is connected with display interface device.
5. Weighing indicator as claimed in claim 4 is characterized in that single-chip microcomputer also is connected with thermal printer by the thermal printer interface.
6. Weighing indicator as claimed in claim 4 is characterized in that single-chip microcomputer also is connected with communication interface with the external printer interface.
7. as the described Weighing indicator of claim 1 to 6, it is characterized in that first bus is a spi bus, second bus is I
2The C bus.
8. Weighing indicator as claimed in claim 1, its feature comprises interface circuit and keyboard matrix at keyboard interface, interface circuit is provided with n root lead-in wire, every lead-in wire connects invalid ground level or the high level of expression key by resistance respectively, it is characterized in that keyboard matrix comprises a plurality of buttons, each marking keys is K
Ij, wherein i represents row, j represents row, and i=0～n-2, j=1～n-1, i＜j, wherein an end of the button of i row all is connected in series with i root lead-in wire, and the other end of the button that j is capable all is connected in series with j root lead-in wire.
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| CN2008100423960A CN101666675B (en) | 2008-09-02 | 2008-09-02 | Weighing indicator |
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| CN2008100423960A CN101666675B (en) | 2008-09-02 | 2008-09-02 | Weighing indicator |
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| CN101666675B true CN101666675B (en) | 2011-06-22 |
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| CN102183286A (en) * | 2011-03-09 | 2011-09-14 | 苏州钮曼精密机电有限公司 | Carrier wave excitation strain type weighing system and excitation method thereof |
| CN102768066A (en) * | 2012-08-14 | 2012-11-07 | 昆山大百科实验室设备工程有限公司 | Intelligent electronic balance |
| CN108189243A (en) * | 2018-02-11 | 2018-06-22 | 成都兴联宜科技有限公司 | A kind of batching electronic scale for concrete stirring |
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|---|---|---|---|---|
| CN2123765U (en) * | 1992-04-24 | 1992-12-02 | 第七砂轮厂 | Abrasive mesh size data analyzer |
| EP1083418A2 (en) * | 1999-09-07 | 2001-03-14 | Cybratech (1998) Ltd. | Configurable electronic component for a scale |
| CN2904149Y (en) * | 2005-12-23 | 2007-05-23 | 上海大华电子秤厂 | Network weighing controller |
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2008
- 2008-09-02 CN CN2008100423960A patent/CN101666675B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2123765U (en) * | 1992-04-24 | 1992-12-02 | 第七砂轮厂 | Abrasive mesh size data analyzer |
| EP1083418A2 (en) * | 1999-09-07 | 2001-03-14 | Cybratech (1998) Ltd. | Configurable electronic component for a scale |
| CN2904149Y (en) * | 2005-12-23 | 2007-05-23 | 上海大华电子秤厂 | Network weighing controller |
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