CN101598930A

CN101598930A - The converter of programmable can bus to analogue signal

Info

Publication number: CN101598930A
Application number: CNA2009101370537A
Authority: CN
Inventors: G·L·里普洛格尔; J·D·克赖尔
Original assignee: International Truck Intellectual Property Co LLC
Current assignee: International Truck Intellectual Property Co LLC
Priority date: 2008-04-22
Filing date: 2009-04-22
Publication date: 2009-12-09

Abstract

Module (10) is connected to the CAN bus in the motor vehicle and the CAN message conversion is become can be by the simulating signal of testing apparatus monitoring.This module also by radio transceiver (28) with PDA (300) radio communication so that PDA can show through the conversion CAN message and select different message to show.

Description

The converter of programmable can bus to analogue signal

Quoting of related application

This application requires the right of priority of the U.S. Provisional Patent Application No.61046970 of submission on April 22nd, 2008.

Background technology

Embodiment disclosed herein relates generally to electronic data is expressed as the electrical system of the CAN message on controller zone network (CAN) bus.Particularly, these embodiment relate to a kind of equipment, and this equipment can be connected to such bus, the CAN message conversion on this bus is become simulating signal and shows decode messages by Bluetooth wireless communication on handheld device.

The electrical system of the motor vehicles of many production in enormous quantities has bus, and data are represented as electronic form on these buses.A kind of example is the CAN data bus.In order to diagnose and/or develop purpose, expect that usually the data on the CAN bus are rendered as analog form, because such presentation mode is concerning checking these data and/or utilizing it to come easier observation the personnel of driving data collecting device.For the technician, the approach that makes things convenient for of observing the rotating speed of the engine moving is to check conformable display, and rotating speed is presented graphically and presents as the function of time sometimes therein.A kind of means that realize this purpose are by near the rotating part that is positioned at engine and transmit the harvester or the sensor of the pulse signal be converted into analog form easily.

When data source is the CAN bus, needs to read the data on the bus and it is converted to the equipment of such display.Be used to realize that the business machine of this purpose sells with " Cubic Labs NC2 " brand.Believe that " Cubic Labs NC2 " equipment utilizes specific program to programme by the computing machine such as laptop computer or desktop computer before must using at the scene.Can understand this programming and be in order to adjust this equipment so that it fetches interested special parameter at the scene, if but be programmed to and fetch this parameter then this equipment can not be reprogrammed at the scene to fetch different parameters.The price of believing " Cubic LabsNC2 " equipment has hindered its being extensive use of in service facility.

Therefore, a kind of more cheap, more general equipment will be used widely, and this will not only help service facility in the automotive industry and attendant but also help service facility and attendant in any industry (being household electrical appliance, aviation and Medical Devices) that machine etc. wherein has the electrical system that comprises the CAN bus.

Summary of the invention

Some embodiment disclosed herein provides a kind of module that is used for the CAN message conversion is become simulating signal.In one embodiment, this module comprises and is provided for this module to the input of the connection of CAN bus with provide one or more connectors of the lead-out terminal of simulating signal.Also comprise the microcontroller that comprises a kind of algorithm, this algorithm is used for searching particular message on the CAN bus, and is used for converting this particular message to proportional pwm signal that output place at microcontroller provides when this particular message occurs on bus.The RC integrator is connected to the output of microcontroller the lead-out terminal of the one or more connectors that provide simulating signal.

Another embodiment provides a kind of system that is used for the CAN message conversion on the motor vehicle CAN bus is become viewdata readable on the display.The module that provides one or more connectors arrives CAN bus and being connected to vehicle power.This module comprises microcontroller, this microcontroller is by the vehicle power power supply and comprise a kind of algorithm, this algorithm is used for searching particular message on the CAN bus, and is used for converting this particular message to signal that output place at microcontroller provides when this particular message occurs on bus.First transceiver is provided, and this first transceiver is used for the conversion of signals one-tenth of output place of microcontroller is sent to the wireless signal of the equipment that comprises display.This equipment comprises second transceiver, and this second transceiver is used to receive wireless signal and converts thereof into viewdata on the display.

The accompanying drawing summary

Fig. 1 is provided with on the panel board top in the motor vehicle electrical system and the stereographic map of the module that effectively is connected with electrical system.

Fig. 2 is the schematic block diagram that a general configuration of this module is shown.

Fig. 3 is the physical circuit figure of this module.

Fig. 4,5 and 6 is the embedded algorithm of relevant microcontroller and a plurality of process flow diagrams that use and operate of configuration sequence.

Fig. 7 is a block diagram of describing to be connected to the node of CAN bus.

Fig. 8 illustrates PDA(Personal Digital Assistant), has shown the data that wirelessly are sent to PDA from module on it.

Embodiment

Fig. 1 illustrates inside and comprises the module 10 that realizes the circuit board of Fig. 3 circuit on it.The panel board that module 10 is placed in the truck pushes up.Circuit from circuit board to the truck electrical system connect by be positioned at connecting respectively of module housing outside the

electric connector

12,14 of matching connector 16,18 set up.From the insulated line the 20, the 22nd of connector 16, the connector (not shown) at the cable other end place of this two wire by being connected to the standard that provides in the truck 9 tunnel diagnosis connectors is connected to the part of the cable of the CAN-H of CAN bus of truck electrical system and CAN-L respectively.Also be connected to the terminal of diagnosis connector from the

insulated line

24,26 of connector 16, these terminals are connected to the truck direct supply that common cell voltage is direct current+12V.This voltage transmits to provide direct current to module 10 by

electric wire

24,26.

Radio transceiver 28 is placed on the top of module 10.A pair of

electric wire

30,32 extends to connector 34 from connector 18, and this connector 34 is connected to the matching connector 36 of transceiver 28 back.Other electric wire by the common mark of Reference numeral 36A is drawn out to connector 38 from connector 18, and this connector 38 is connected to the matching connector 40 of transceiver 28 fronts.

Electric wire

30,32 offers transceiver with direct current.From the electric wire of matching connector 40 the numeral output of module is offered transceiver.The actual connection of each bar electric wire will be in the detailed view of Fig. 3 as seen.The block diagram of Fig. 2 illustrates after a while will carry out the more primary element of complete description with reference to the detailed view of figure 3.These primary elements are microcontroller 50, CAN transceiver 52 and RS232 transceiver 54.Oscillator 56 control microcontrollers 50 are in order to the speed of deal with data.

Just now the element of describing shown in Figure 3 and other element that comprises stabilized

voltage supply

58,60 and reset circuit 62 and so on.The wiring title is continued to use in Fig. 3, but is to be understood that electric wire from the connector among Fig. 3 12 and 14 is in module 10 inside.Because pulse-length modulation (PWM) signal and this signal of microcontroller 50 output expression CAN parameter values are imported into

CAN transceiver

52,64,66 pairs of pwm signal integrations of RC integrator are to provide the simulating signal by the output transmission at connector 14 places.One of two

integrators

64,66 are the surface attaching type devices with constant frequency response.Another of two

integrators

64,66 is changed with the value that allows them by the discrete assembly composition that is arranged separately on the circuit board, thereby changes the frequency response of this integrator.The electric wire 36A of bunchy comprises electric wire 36TX, 36RX, 36INT1 and 36INT2 among Fig. 3.Be sent to transceiver 28 through decoding CAN message by electric wire 36TX, and transceiver 28 is sent to module 10 from the signal that PDA 300 (Fig. 8) receives from transceiver.Simulating signal from

integrator

64,66 sends by electric wire 36INT1 and 36INT2.

Fig. 4 illustrates the process flow diagram of module 10 configuration microcontrollers with the task of description before carrying out.First step 80 comprise in the initialization microcontroller 50 the CAN module so that its can read the CAN data and convert thereof into the form that can produce corresponding pwm signal according to it.Second step 90 comprises that the PWM module in the initialization microcontroller 50 is so that form pwm signal.Third step 100 comprises the USART module of configuration in the microcontroller 50, and this makes CAN data through conversion be sent to RS232 with digital format and enables device.

In case the module in the microcontroller 50 is configured, microcontroller just begins the reception buffer (step 110) of poll transceiver 52.Poll continues up to receiving message (step 120).This message is read to judge whether it is interested special parameter, is engine speed (step 130) in this example.If it is not a parameters of interest, then this message is left in the basket and continues poll.

In case received the message interested such as engine speed message, microcontroller 50 just carries out message conversion is become the calculating of numerical data according to agreement, and agreement is SAE J1939 (step 140) in this example.Numerical data is handled (step 150) by the USART module in the microcontroller 50.If engine does not move, then serial data is represented the engine speed (step 160) that per minute zero changes, and the width of pwm signal is set to 1%.Begin to search rotating speed message (step 170) in step 110 through upgrading.

When this numerical data is represented the engine speed of non-zero, must judge that whether this rotating speed allows engine speed greater than the maximum that limits, and changes (step 180) such as per minute 3000 in this example.If like this, then the width of pwm signal is set to 100% (step 190).

If numerical data is represented the non-zero engine speed less than maximum permissible speed, then the width of pwm signal is scaled out into the appropriate percentage (step 200) by the limited proportion of this non-zero rotating speed and 3000.

No matter number percent is from step 160,170,180,190, still 200 generations, and the width of pwm signal all has this number percent.

Fig. 5 illustrates and makes microcontroller 50 be ready to read data value on the CAN bus of truck to prepare to produce detailed process Figure 80 of pwm signal.

Fig. 6 illustrates the detailed process Figure 90 for preparing pwm signal.As the part of initialization procedure, two timers (timer 2 and timer 3) have been disposed in microcontroller and oscillator (in the microcontroller outside) 50 inside.Timer 2 helps to be provided with the cycle of pwm signal; The sequential of oscillator is as making timer progressively accelerate to the multiplier of appropriate frequency.During each cycle that is provided with by timer 2, timer 3 operations are corresponding to the time span of predetermined value (500 circulations); This is provided with the time base of PWM.After 500 circulations have been finished, be used to be provided with the dutycycle of PWM from the definite in proportion then value of CAN bus collection; Select one of two integrators so that simulating signal to be provided, this simulating signal will be fed to radio transceiver 28 and wirelessly will be sent near personal digital assistant (PDA) (being the article 300 Fig. 8), display engine rotary speed data thereon from radio receiver.

As long as PDA 300 can move LabView (software that national instrument company sells), just numerical value ground and figure ground show data simultaneously.Demonstration 320 on the PDA is the electronic simulation pointers that are similar to the pointer of air-core gauge general on the instrument panel of motor vehicle.PDA 300 also has the ability that sends to module 10, and this ability makes parameters of interest to be changed.In order to realize this purpose, PDA has the control 310 of the table that is used to call the different parameters of interest such as engine speed, oil temperature, air-distributor pressure or the like.On PDA display 320, call this table, and utilize control to select interested special parameter.In case made this selection, the PDA control just moves so that this selection is sent to module 10.

PDA is undertaken by transceiver 54 with communicating by letter of microcontroller 50.Can use being used to such as bluetooth to set up any known technologies useful of communication.Independent cable is connected the diagnosis of 9 tunnel in module 10 and truck connectors.This cable comprises the termination resistor at the place, two ends as shown in Figure 7.

Claims

1. module that is used for the CAN message conversion is become simulating signal, described module comprises:

The lead-out terminal that one or more connector, described one or more connector are provided for connecting the input of described module and CAN bus and provide described simulating signal;

The microcontroller that comprises an algorithm, described algorithm is used for searching particular message on described CAN bus, and is used for converting described particular message to proportional pwm signal that output place at described microcontroller provides when described particular message occurs on described bus; And

The RC integrator, described RC integrator is connected to the described output of described microcontroller the lead-out terminal of described one or more connector that provides described simulating signal.

2. module as claimed in claim 1, it is characterized in that, described one or more connector comprises input terminal, and described input terminal also is connected to described module when the terminal of described one or more connector is connected to the CAN bus galvanic direct supply is provided.

3. module as claimed in claim 2 is characterized in that described module also comprises transceiver, and described microcontroller is connected to described CAN bus by described transceiver.

4. module as claimed in claim 3 is characterized in that, also comprises

Be connected described transceiver is connected to the cable of described CAN bus in described module-external and with described one or more connector of described module, the two ends of described cable between each bar electric wire have termination resistor, and described module is wired to described CAN bus by described.

5. module as claimed in claim 1, it is characterized in that, described microcontroller algorithm utilizes first timer and second timer to produce pwm signal, and described first timer is configured to limit the cycle of pwm signal, and described second timer is configured to limit the time base of described pwm signal.

6. module as claimed in claim 1 is characterized in that, also comprises

Be connected to the radio transceiver of described module, described radio transceiver is used for described decoding CAN message wirelessly is sent to the remote equipment that comprises the display of the described signal of demonstration on it.

7. module as claimed in claim 6 is characterized in that, also comprises

Transceiver, described microcontroller are connected with described radio transceiver by described transceiver so that described remote equipment can be arranged to described microcontroller to select one of specific in a plurality of message on the described CAN bus.

8. system that is used for the CAN message conversion on the motor vehicle CAN bus is become viewdata readable on the display comprises:

One or more connector, described one or more connector provide module to arrive described CAN bus and being connected to described vehicle power;

Described module comprises microcontroller, described microcontroller is by described vehicle power power supply and comprise an algorithm, described algorithm is used for searching particular message on described CAN bus, and is used for converting described particular message to signal that output place at described microcontroller provides when described particular message occurs on described bus;

First transceiver, described first transceiver are used for the described conversion of signals one-tenth of output place of described microcontroller is sent to the wireless signal of the equipment that comprises described display; And

Described equipment comprises second transceiver, and described second transceiver is used to receive described wireless signal and converts thereof into viewdata on the described display.

9. system as claimed in claim 8, it is characterized in that, described equipment comprises control, described control is used to select on the described CAN bus interested special parameter and makes selected parameter wirelessly be sent to described first transceiver from described second transceiver, and described first transceiver makes described selected parameters of interest be read and handle so that wirelessly send it back described equipment from described CAN bus by described microcontroller.