A kind of supervising device to the output of electric current input voltage
Technical field
The present invention relates to device to using the end product applied voltage to protect.More particularly say, be meant a kind of can be to the analog current I of 4~20mA of input
Electric currentConvert the aanalogvoltage V of 0~5V to
VoltageOutput, and aanalogvoltage V to not satisfying condition and exporting
VoltageThe supervising device of reporting to the police.
Background technology
For using end product, use a kind of supply unit of stable performance can protect its serviceable life fully.Using terminal can be portable equipment (as mobile phone, PDAS, GPRS, game machine), telecommunications/network equipment (as router, server, VOIP system), consumer electronics, medical system, navigational system etc.These commercial units are standard with 0~5V voltage mostly, and a large amount of 4~20mA current signals is contained in its circuit inside.These tiny signals in use very easily are subjected to the influence of external environment (as electromagnetic field, temperature etc.), and cause the damage or the lower signal to noise ratio (S/N ratio) of output signal of internal components, give and use the application of end product to bring huge hidden danger.Therefore, a kind of stable, reliable, highly sensitive, easy-operating electric current and voltage supervising device meaning concerning commercial production and application is huge.
At present, similar electric current on the market changes the following three kinds of methods of the general employing of product of voltage: (1) replaces voltage signal to handle with the electric current signal Processing, compare with voltage signal, MOS transistor is more suitable for handling current signal, because common source in the structure for amplifying and common gate output signal are current signal.(2) according to the principle design equivalent current transmitter structure of operational amplifier and current transmission device (CCII), by the replacement of operational amplifier and equivalent current transmitter structure thereof and in conjunction with the adjoint network theorem, can with the voltage-type circuit conversion current mode circuit of voltage-operated signal and current practice signal.(3) adopt standard capacitance, operational amplifier, feedback resistance, battery and charging circuit to come design voltage and the electric current circuit of commentaries on classics mutually by the selection and the calculating of concrete device.
Summary of the invention
Use terminal to be unlikely to the invention provides a kind of supervising device to the output of electric current input voltage because of voltage surpasses the use terminal damage that the scope of application causes in order to protect, this supervising device adopts the digital voltage signal V to receiving in central processing unit
InCarry out the operating voltage V of one 12 bit value of differential ference spiral acquisition
OutThis operating voltage V
OutOne side is as the input digit voltage signal of aanalogvoltage conversion, on the other hand with operating voltage V
OutWith voltage threshold P
InCompare and obtain alarm voltage, thereby the effect of early warning and protection is played in realization to the damage of using the terminal overvoltage to cause.
A kind of supervising device of the present invention to the output of electric current input voltage, this supervising device includes a housing, and is installed in the circuit board in the housing; Be provided with current interface (J3), voltage interface (J2) and remote alarm interface (J6) on the top panel of housing, the right panel of housing is provided with power interface (J1), and the front panel of housing is provided with LCD display and keyboard;
Power interface (J1) is used for being connected with the direct current of 220V;
Current interface (J3) is used for and can exports 4~20mA analog current signal I
Electric currentEquipment connect;
Voltage interface (J2) is used for being connected with using end product;
Remote alarm interface (J6) be used to provide audible alarm;
Circuit board includes:
One central processing unit, range S and ratio K and the digital voltage signal V of this central processing unit to setting among the command information INF that receives
InCarry out difference processing and obtain the operating voltage V of 12 bit values
OutThis operating voltage V
OutExport the demonstration of the enterprising line number font of LCD MODULE formula on the one hand to; This operating voltage V on the other hand
OutBe output to alarm output module; In alarm output module, this operating voltage V
OutWith voltage threshold P
InCompare, work as V
Out〉=P
InThe time, alarm output module produces alerting signal and carries out alarm; Work as V
Out<P
InThe time, with the operating voltage V of 12 bit values
OutExport to D/A converter module;
One analog-to-digital conversion module, this analog-to-digital conversion module are used for the 4~20mA analog current signal I with the outside input
Electric currentConvert digital voltage signal V to
InOffering central processing unit handles;
The 12 bit value operating voltage V that one D/A converter module, this D/A converter module will receive
OutCarry out exporting after the digital-to-analog conversion analog voltage signal V of 0~5V
Voltage
One alarm output module, this alarm output module is used for the output of warning message;
One keyboard issues command information INF by this keyboard to central processing unit, and this order information INF includes range S, ratio K and voltage threshold P
In
One LCD MODULE, this LCD MODULE are used to carry out the information that digital form shows each input, output.
The advantage of a kind of supervising device to electric current input voltage output of the present invention is:
(1) 4~20mA analog current signal I that the outside is imported
Electric currentCarry out providing digital voltage signal V for central processing unit after the analog to digital conversion
In
(2) the digital voltage signal V of difference algorithm to receiving of application C language compilation in central processing unit
InHandle, improved precision the input voltage monitoring.
(3) (command information INF includes range S, ratio K and voltage threshold P to issue command information INF by keyboard operation
In), this command information INF can change voluntarily, set according to the actual demand of using terminal, has improved the flexibility of operation of supervising device of the present invention.
(4) 4~20mA analog current signal I
Electric currentInput, and 0~5V analog voltage signal V
VoltageOutput, be common simulating signal in the commercial Application now, solved stability and the accuracy requirement of using terminal that electric current is needed, thereby protected the use terminal effectively.
Description of drawings
Fig. 1 is a structural representation of using supervising device of the present invention.
Figure 1A is the external structure schematic diagram of supervising device of the present invention.
Fig. 2 is the structured flowchart of supervising device of the present invention.
Fig. 3 A is the circuit theory diagrams of the central processing unit in the supervising device of the present invention.
Fig. 3 B is the circuit theory diagrams of the 220V power module in the supervising device of the present invention.
Fig. 3 C is the keyboard interface in the supervising device of the present invention.
Fig. 3 D is the liquid crystal interface in the supervising device of the present invention.
Fig. 3 E is the circuit theory diagrams of the analog-to-digital conversion module in the supervising device of the present invention.
Fig. 3 F is the circuit theory diagrams of the D/A converter module in the supervising device of the present invention.
Fig. 3 G is the circuit theory diagrams of the alarm output module in the supervising device of the present invention.
Embodiment
The present invention is described in further detail below in conjunction with accompanying drawing.
Referring to shown in Figure 1, the supervising device of electric current input voltage output of the present invention is mounted in and uses terminal and can export 4~20mA analog current signal I
Electric currentEquipment between.This supervising device can be protected and use terminal to be unlikely to cause damage because of voltage surpasses the scope of application.
Shown in Figure 1A, the supervising device of electric current input voltage output of the present invention includes a housing, and is installed in the circuit board in the housing.On the top panel of housing, be provided with current interface J3, voltage interface J2 and remote alarm interface J6, the right panel of housing is provided with power interface J1, the front panel of housing be provided with LCD display and keyboard (0-9 numeral arranged on this keyboard, and commonly used as determine, key such as cancellation).LCD display is used to show that (command information INF includes range S, ratio K and voltage threshold P to the command information INF that issues by keyboard
In), the easy operating person to the actual demand of using end product change voluntarily, visual when setting.Power interface J1 is used for being connected with the direct current of 220V.Current interface J3 is used for and can exports 4~20mA simulating signal I
Electric currentEquipment connect.Voltage interface J2 is used for being connected with using end product.Remote alarm interface J6 is used for and is connected as loudspeaker, and audible alarm is provided.
Referring to shown in Figure 2, the board structure of circuit figure of a kind of supervising device to electric current input voltage output of the present invention includes on this circuit board:
One central processing unit, range S and ratio K and the digital voltage signal V of this central processing unit to setting among the command information INF that receives
InCarry out difference processing and obtain the operating voltage V of 12 bit values
OutThis operating voltage V
OutExport the demonstration of the enterprising line number font of LCD MODULE (LCD) formula on the one hand to; This operating voltage V on the other hand
OutBe output to alarm output module; In alarm output module, this operating voltage V
OutWith voltage threshold P
InCompare, work as V
Out〉=P
InThe time, alarm output module produces alerting signal and carries out alarm; Work as V
Out<P
InThe time, with the operating voltage V of 12 bit values
OutExport to D/A converter module;
One analog-to-digital conversion module, this analog-to-digital conversion module are used for the 4~20mA analog current signal I with the outside input
Electric currentConvert digital voltage signal V to
InOffering central processing unit handles;
The 12 bit value operating voltage V that one D/A converter module, this D/A converter module will receive
OutCarry out exporting after the digital-to-analog conversion analog voltage signal V of 0~5V
Voltage
One alarm output module, this alarm output module is used for the output of warning message;
One keyboard issues command information INF by this keyboard to central processing unit, and this order information INF includes range S, ratio K and voltage threshold P
In
One LCD MODULE, this LCD MODULE are used to carry out the information that digital form shows each input, output.
The supervising device of a kind of electric current input voltage output of the present invention, its central processing unit is chosen the ATmega128 chip, and the modulus conversion chip in the analog-to-digital conversion module is chosen the MAX187 chip, and the analog-digital chip in the D/A converter module is chosen the MAX5712 chip.The circuit of this supervising device under each chip portfolio of choosing connects:
Shown in Fig. 3 A, Fig. 3 B, Fig. 3 C, 8 terminals of 10 ends of central processing unit U1~17 ends join with 1 end~8 ends of the interface J4 of keyboard respectively, realize that keyboard is connected on the central processing unit U1; Keyboard is connected with central processing unit, has realized issuing command information INF by keyboard operation to central processing unit.In the present invention, described command information INF includes the voltage threshold P when reporting to the police at least
In, by keyboard operation the range S (0~9999) of input voltage is set, under alarm condition as the digital voltage signal V of analog-to-digital conversion module output
InBe lower than voltage threshold P
InIn time, sounds all clear (resetting), by keyboard output voltage V be set by operation keyboard
VoltageRatio K (0<K≤9.9).In the present invention, the voltage of 220V enters to exchange through power interface J1 to be changeed among the direct current chip U5, changes direct current chip U5 through this interchange and converts 5V voltage to as the supervising device use of VCC for whole electric current input voltage output of the present invention.
Shown in Fig. 3 D, 8 terminals of 25 ends of central processing unit U1~32 ends join with 7 ends~14 ends of the interface J5 of LCD MODULE respectively, 36 ends of central processing unit U1,37 ends, 38 ends respectively with 4 ends of LCD interface J5,5 ends, 6 ends join, the 2 termination 5V power supplys of the interface J5 of LCD MODULE, 3 ends are connected on 2 ends of adjustable resistance R27, the 1 termination 5V power supply of adjustable resistance R27, the 3 end ground connection of adjustable resistance R27,1 end of the interface J5 of LCD MODULE is connected on 3 ends of adjustable resistance R27, the 16 end ground connection of the interface J5 of LCD MODULE, 15 ends of the interface J5 of LCD MODULE connect the 5V power supply after resistance R 32; LCD MODULE is connected with central processing unit, has realized carrying out the information that digital form shows each input, output by LCD MODULE.
Shown in Fig. 3 E, in analog-to-digital conversion module, analog-to-digital conversion module receives the 4~20mA analog current I by the outside input
Electric current, this electric current I
Electric currentAt first behind a filtering circuit filtering ripple, through resistance R 2 with this electric current I
Electric currentBe converted to corresponding voltage, this voltage is connected on 2 ends of modulus conversion chip U2 through a resistance R 3 again, and filtering circuit is made up of diode D1 and capacitor C 5, and diode D1 and capacitor C 5 are connected in parallel on electric current I
Electric current(current interface J3) and digitally between; For current conversion is become voltage, between 1 end of current interface J3 and 2 ends, be in series with resistance R 2; 8 ends of modulus conversion chip U2,7 ends, 6 ends join with 47 ends, 49 ends, 48 ends of central processing unit U1 respectively, the 5 end ground connection of modulus conversion chip U2, the 1 termination 5V power supply of modulus conversion chip U2, the 3 termination 5V power supplys of modulus conversion chip U2, and 3 ends and digitally between be connected to another filtering circuit, this filtering circuit is made of capacitor C 6 and capacitor C 7, this capacitor C 6 and capacitor C 7 be connected in parallel on 3 ends and digitally between, 4 ends are through capacitor C 8 ground connection.
Shown in Fig. 3 F, in the present invention, the 1 termination 5V power supply of analog-digital chip U3,2 end ground connection, 3 ends, 4 ends, 5 ends join with 61 ends, 60 ends, 59 ends of central processing unit U1 respectively, and 6 ends are connected with 1 end of voltage interface J2, the 2 end ground connection of voltage interface J2.By voltage interface J2 with use being connected of terminal, realization is supplied with the stable voltage with 0~5V and is used terminal.Being connected of three terminals on three terminals on the analog-digital chip U3 and the central processing unit U1, realized that D/A converter module receives from Gong the operating voltage V of central processing unit output
Out
Shown in Fig. 3 G, alarm output module at first receives from the high-low level signal PC5 of the 40 ends output of central processing unit U1, this height electricity signal PC5 frequently connects the 5V power supply after resistance R 34, and this high-low level signal PC5 is again through being connected to after the resistance R 35 on the base stage of triode Q9; The emitter of triode Q9 is connected on 2 ends of relay K 1, the grounded collector of triode Q9; Be parallel with diode D11 between 2 ends of relay K 1 and 1 end, and 1 termination 5V power supply, 3 ends of relay K 1,4 ends and 5 ends are as the switch of alerting signal output, and alerting signal output interface J6 can join with loudspeaker, realizes the broadcast of alarm sound.In the present invention, it is 8550 that triode Q9 chooses model, and it is TQ2-5V that relay K 1 is chosen model.
The supervising device of a kind of electric current input voltage output of the present invention can be with 4~20mA analog current signal I
Electric currentInput, and 0~5V analog voltage signal V
VoltageOutput, be common simulating signal in the commercial Application now, solved stability and the accuracy requirement of using terminal that electric current is needed, thereby protected the use terminal effectively.