JP3842453B2 - Error canceling method and error canceling device for analog data transmission between controllers of construction machinery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for canceling an error in analog data transmission in a construction machine such as a hydraulic excavator that includes a plurality of controllers and transmits and receives analog data between the controllers.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is an electronic control system using a controller composed of a digital computer in operation control of, for example, a hydraulic excavator. This controller is disposed, for example, in the vicinity of the cab and has a function of controlling the operation of the working machine in the hydraulic excavator or the operation of the diesel engine related to the operation of the traveling body. Conventional hydraulic excavators do not require such a high function in terms of operation, and as a result, the control function of a controller using a digital computer is relatively simple. However, in recent years, there has also been a tendency for more precise control to be required for hydraulic excavators.
[0003]
In the case where various operations are controlled by a controller using a digital computer in a hydraulic excavator, in order to achieve a desired control state, a system configuration based on distributed controllers is proposed. For example, a configuration is conceivable in which a main controller is disposed in the vicinity of the cab and a dedicated controller for controlling only the fuel injection amount of the engine is disposed in the vicinity of the diesel engine. The engine-dedicated controller is preferably disposed near the diesel engine, but may be disposed near the cab. In the above, the main controller functions as a transmission side controller that provides necessary information for control to the sub controller, and the sub controller is positioned so as to function as a reception side controller that receives necessary information from the main controller.
[0004]
When data is transmitted between controls in a system configuration using the above-described controller distributed system structure, digital communication that does not depend on the voltage used in each controller can be used from the viewpoint of general transmission control. desired. However, using digital communication increases the cost because dedicated hardware is required. For advanced information transmission, its use can be considered, but for example when the main controller transmits necessary data to a simple controller that controls only the fuel injection amount of the diesel engine of a hydraulic excavator as described above, High costs are not realistic. In other words, when relatively simple data transmission is performed from the main controller to the sub-controller, data transmission by analog data is advantageous in terms of cost. In other words, when the amount of information necessary for the control operation of the controller is small as in the case where information corresponding to the engine speed is required as described above, it is advantageous in terms of cost to employ transmission by analog data.
[0005]
[Problems to be solved by the invention]
As described above, in the electronic control system of a hydraulic excavator, when data is transmitted from at least two controllers, that is, the main controller and the sub-controller, from the main controller on the transmitting side to the sub-controller on the receiving side, data transmission between the controllers is required. The following problems arise in the configuration configured to use analog data. In the main controller, data is handled as digital in the digital processing section, and this digital data must be converted into analog data by a D / A converter for transmission. On the other hand, since the sub-controller performs data processing with digital data in its digital processing section, the transmitted analog data must be converted into digital data by an A / D converter. In the transmitting main controller and the receiving sub controller, each D / A converter and A / D converter is supplied with a reference voltage from a reference voltage source, and a conversion operation is performed based on the reference voltage. Yes. Essentially, it is ideal that the reference voltages of the main controller and the sub-controller are completely the same, and if it is not the same, highly accurate information cannot be transmitted from the transmitting controller to the receiving controller. However, in actuality, when comparing the reference voltages of the transmission side controller and the reception side controller, the reference voltage in the sub controller on the reception side generally tends to decrease due to reasons specific to the circuit or due to ambient temperature characteristics. There is also a problem that an output error occurs. For this reason, conventionally, the circuit must be designed so that the output error of the reference voltage of the A / D converter in the receiving controller is as small as possible, and the ambient temperature in the transmitting controller and the receiving controller is further reduced. The circuit design is made so that the temperature characteristics caused by the above are as equal as possible.
[0006]
That is, the voltage source of the reference voltage supplied to the D / A converter of the transmission side controller and the voltage source of the reference voltage supplied to the A / D converter of the reception side controller are designed to be the same circuit. Circuit adjustment and the like had to be performed so as to minimize the voltage error between the two controllers.
[0007]
However, in at least two controllers installed on a hydraulic excavator, such adjustment is troublesome and has a problem that it easily varies depending on various environments. Furthermore, such adjustment was almost impossible if at least two controllers to be mounted were provided by different manufacturers.
[0008]
The above problem is not only a problem with a hydraulic excavator, but is a problem that can generally occur with a construction machine that operates in a similar environment and has a similar control system.
[0009]
An object of the present invention is to solve the above-described problem, and includes at least two controllers including a digital processing unit as an electronic control system in a hydraulic excavator or the like, and performs transmission with analog data between these controllers. When a D / A converter or an A / D converter is included, even if the reference voltage for the converter fluctuates and an error occurs, a construction machine that can easily solve the problem and correctly transmit analog data It is an object to provide an error canceling method and an error canceling device for analog data transmission between controllers.
[0010]
Another object of the present invention is to perform error analysis by performing failure analysis when a disconnection occurs in a signal transmission path between controllers, and the above-described error canceling method useful from the viewpoint of safety. An object of the present invention is to provide an error canceling device.
[0011]
[Means and Actions for Solving the Problems]
In order to achieve the above object, an error canceling method for analog data transmission between controllers of a construction machine according to the present invention is configured as follows.
A first error canceling method (corresponding to claim 1) includes a first controller (a main controller on the transmission side) including a digital processing unit (CPU circuit) and a D / A conversion unit in a construction machine, and a digital processing unit (CPU circuit). ) And a second controller (sub-controller on the receiving side) including an A / D converter, and transmit analog data from the D / A converter of the first controller to the A / D converter of the second controller It is a method applied to what is comprised by. Further, it is assumed that a first reference voltage source for supplying a reference voltage to the D / A converter is provided in the first controller, and a second reference voltage source for supplying the reference voltage to the A / D converter is provided in the second controller. The error canceling voltage is transmitted from the first reference voltage source to the digital processing unit of the second controller through the A / D converter, and the digital processing unit outputs the reference voltage output from the first reference voltage source and the second voltage This is a method of canceling an analog data transmission error caused by a difference between reference voltages output from a reference voltage source with an error canceling voltage (corresponding to a reference voltage described later).
In the above error canceling method, an error canceling voltage, that is, a reference voltage is sent from the first controller to the second controller, and a ratio conversion process is performed using this error canceling voltage, so that it occurs in the second controller on the receiving side. Thus, the difference caused by the fluctuation of the reference voltage is eliminated, the error of the data obtained on the receiving side is canceled, and correct data is obtained.
In the above method, the second error canceling method (corresponding to claim 2) is preferably a device in which the second controller controls the fuel injection amount of the diesel engine, and the first controller controls the fuel injection amount of the diesel engine. It is a device that sends information on the engine speed necessary for the operation as analog data. Since only simple data such as engine speed information is sent, transmission by analog data is most desirable in terms of cost.
In the third error canceling method (corresponding to claim 3), in the above method, the error canceling voltage is preferably obtained by dividing the reference voltage output from the first reference voltage source. In the second controller on the receiving side, the reference voltage tends to decrease from the original value due to its ambient temperature characteristics and the like, so it is desirable in terms of circuit design to transmit a low voltage value as an error canceling voltage by voltage division. .
According to a fourth error canceling method (corresponding to claim 4), in the above method, preferably, the digital processing unit of the second controller performs a ratio conversion process on the analog data by using the ratio of the error canceling voltage. The correct ratio of analog data is calculated. The analog data error caused by the transmission error is canceled at a ratio obtained with respect to the error cancel voltage, and correct digital data is obtained.
In order to achieve the above object, an error canceling apparatus for analog data transmission between controllers of a construction machine according to the present invention is configured as follows. This error canceling device is a device that implements the above-described error canceling method.
A first error cancellation device (corresponding to claim 5) includes a first controller including a digital processing unit and a D / A conversion unit, and a second controller including a digital processing unit and an A / D conversion unit. Applied to construction machines configured to transmit analog data from the D / A converter of one controller to the D / A converter of the second controller, and provides a reference voltage to the D / A converter in the first controller A first reference voltage source is provided, a second reference voltage source for supplying a reference voltage to the A / D converter is provided in the second controller, and the first controller is used for error cancellation from the first reference voltage source to the A / D converter. A circuit for sending a voltage is provided, and the digital processing unit of the second controller is configured to analyze the difference between the reference voltage output from the first reference voltage source and the reference voltage output from the second reference voltage source. Transmission error of Gudeta is configured to include a canceling means for canceling the error canceling voltage.
In the above configuration, the second error canceling device (corresponding to claim 6) is preferably a device for controlling the fuel injection amount of the diesel engine, and the first controller is a fuel injection amount of the diesel engine. It is a device that sends engine speed information necessary for control as analog data.
In the third error canceling device (corresponding to claim 7), in the above configuration, the circuit for sending the error canceling voltage is preferably a voltage dividing circuit.
In the fourth error canceling device (corresponding to claim 8), in the above configuration, the canceling unit preferably performs ratio conversion processing on the analog data using the ratio of the error canceling voltage, It is characterized by calculating a correct ratio.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
[0013]
The error canceling method or error canceling apparatus for analog data transmission between controllers according to the present invention is preferably a sub controller provided for controlling the fuel injection amount of the main controller 100 and the diesel engine 19 in the hydraulic excavator shown in FIG. Applies to analog data transmission between 200.
[0014]
The hydraulic excavator includes a lower traveling body 11 provided with a traveling hydraulic motor (not shown) and the like, and a turning device provided on the lower traveling body 11 and configured to be rotatable by a turning hydraulic motor (not shown). 12 and an upper swing body 13 as a work machine body mounted on the lower traveling body 11 by the swing device 12 so as to be swingable. Further, the upper swing body 13 includes a swing frame 14 having a skeleton structure, a driver's cab 15 provided on the front side of the swing frame 14, and a counter provided on the swing frame 14 at the rear side of the driver's cab 15. The weight 16 is composed of a working device 17 and a machine room 18. The working device 17 includes a boom 17A that is rotatably provided at the front portion of the revolving frame 14, an arm 17B that is rotatably provided at the distal end side of the boom 17A, and a bucket that is provided at the distal end side of the arm 17B. 17C, which are driven by a boom cylinder 17D, an arm cylinder 17E, and a bucket cylinder 17F, respectively. The machine room 18 is formed in a box shape, and a diesel engine 19 is provided in the box-like machine room 18. The diesel engine 19 is provided with a heat exchanger such as a cooling fan and a radiator attached to a rotation output shaft of the engine, a hydraulic pump (not shown), and the like.
[0015]
In the hydraulic excavator, pressure oil is appropriately applied from the hydraulic pump in the machine room 18 to the traveling hydraulic motor of the lower traveling body 11, the turning hydraulic motor of the turning device 12, and the cylinders 17D, 17E, and 17F of the working device. By supplying, operations such as traveling, turning, excavation, and various operations are performed. This hydraulic excavator is controlled by a control system composed of a digital computing unit (digital computer) in controlling the operation of a hydraulic valve for operating the working device 17 or the operation of the diesel engine 19. Furthermore, this control system is configured as a distributed control system by a main controller 100 having a function of executing various controls and a sub-controller 200 configured to perform only fuel injection amount control of the diesel engine 19. . Both the main controller 100 and the sub controller 200 include a digital processing unit (CPU circuit), and various control calculations are performed by digital processing. The sub controller 200 that controls only the fuel injection amount of the diesel engine 19 is configured to receive information on the engine speed transmitted from the main controller 100, and the engine speed information is received from the main controller 100 as analog data. 200.
[0016]
FIG. 2 shows only a part of the above-described control system mounted on the hydraulic excavator. The main controller 100 disposed in the cab 15 is a control device that mainly performs various controls, and is output from an operation device 21 (an assembly of operation means) such as an operation lever provided in the cab 15. An operation signal is configured to be input. For example, a detection signal from an engine speed sensor 22 attached to the diesel engine 19 is also input to the main controller 100. Furthermore, various sensors are provided in each part of the actual vehicle body or each part of the work device 17, and detection signals are input to the main controller 100 from these sensors. The main controller 100 performs various computation commands based on various command signals related to operations given from the operation device 21 and detection signals given from various sensors including the engine speed sensor 22, and various control command signals required. And generate data. These control command signals and the like are given to another control object 23. When viewed from the main controller 100, the sub-controller 200 is substantially a control target for providing necessary data. As described above, the sub controller 200 is an engine-dedicated controller for optimally controlling the fuel injection amount of the diesel engine 19. Since the information on the rotational speed of the diesel engine 19 is necessary for controlling the fuel injection amount, the sub controller 200 is configured to receive the engine rotational speed data transmitted from the main controller 100. The signal s1 transmitted from the main controller 100 to the sub controller 200 is analog data relating to information on the engine speed. The sub controller 200 receives the analog data s 1, generates a control command signal related to the fuel injection amount control of the diesel engine 19 using the engine speed information, and provides the control command signal to the diesel engine 19.
[0017]
FIG. 3 shows an example of the internal configuration of the main controller 100 and the sub controller 200 and the configuration of the transmission path 24 connecting them. FIG. 3 shows the first embodiment. In FIG. 3, the transmission line 24 is a single common cable. The main controller 100 on the transmission side includes a reference voltage V to the CPU circuit 101, the D / A converter 102, and the D / A converter 102. ₀ Reference voltage source 103 and reference voltage V ₀ Is divided by a voltage V smaller than that ₁ Is included. The CPU circuit 101 is a digital arithmetic processing unit. The CPU circuit 101 performs arithmetic processing for various controls and generates a control command signal. The CPU circuit 101 and the D / A converter 102 are connected by a bus line 105. This D / A converter receives the information on the engine rotational speed sent from the CPU circuit 101 through the bus line 105 as digital data, converts it into analog data, and transmits it to the sub controller 200 on the receiving side. Means. The operation of the digital / analog conversion in the D / A converter 102 is the reference voltage V output from the reference voltage source 103. ₀ It is done using. Reference voltage V ₀ Is divided into lower voltage V ₁ The voltage dividing circuit 104 for generating the voltage V ₁ Is given as a reference voltage. A terminal provided at the lower end of the D / A converter 102 is grounded. The lines drawn from the transmission side main controller 100 to the reception side sub controller 200 are a line 25 for sending analog data s1 relating to information on the engine speed, and a reference voltage V outputted from the voltage dividing circuit. ₁ Are a line 26 for transmitting the signal and a ground line 27. As described above, the lines 25, 26, and 27 are bundled as one transmission line 24 and connected to the receiving side sub controller 200.
[0018]
In the main controller 100, in practice, an input / output unit that receives an operation signal from the operating device 21, an input / output unit that receives detection signals sent from various sensors, and a control command signal to other control objects 23. Although an input / output unit and the like for sending are provided, they are not shown in FIG. 3 for convenience of explanation.
[0019]
On the other hand, the sub controller 200 on the receiving side controls the fuel injection amount by executing an A / D converter 201 that converts the analog data s1 sent from the main controller 100 side into digital data, a cancel method that will be described later, and the like. CPU circuit 202 for generating a control command signal for performing the operation, and a reference voltage V for A / D converter 201 ₀ A reference voltage source 203 is provided. The lower terminal of the A / D converter 201 is grounded. The reference voltage source 203 has substantially the same circuit configuration as the above-described reference voltage source 103, and ideally the reference voltage V having the same value. ₀ Is supplied to the A / D converter 201. The analog data s1 sent through the line 25 and the reference voltage V sent through the line 26. ₁ Is input to the A / D converter 201. Analog data s1 converted to digital data by the A / D converter 201 and the reference voltage V ₁ Is supplied to the CPU circuit 202 through the bus line 204. The ground line 27 is connected to the ground terminal of the A / D converter 201. In the CPU circuit 202, the reference voltage V input as described later. ₁ The reference voltage V output from the reference voltage source 203 using ₀ The fluctuation state is checked, the error due to the fluctuation is corrected, and the original correct engine speed data is extracted. Then, a control command signal for controlling the fuel injection amount is generated using correct engine speed data. The control command signal generated by the CPU circuit 202 is given to the diesel engine 19 as shown in FIG. 2, but the configuration of the input / output unit and the like is omitted in the illustrated example of FIG.
[0020]
In the configuration shown in FIG. 3, it is assumed that the reference voltage source 103 on the transmission side and the reference voltage source 203 on the reception side are substantially the same in terms of electrical circuits. Accordingly, the reference voltage on the transmission side and the reference voltage on the reception side are maintained at the same voltage value as long as there are no external fluctuations or environmental fluctuations and the ideal state in circuit design is maintained. However, in actuality, the sub controller 200 on the receiving side is arranged in a slightly bad environment, so that the reference voltage V ₀ Fluctuates. Usually, reference voltage V ₀ Changes in the direction of decreasing its value. Therefore, the reference voltage V of the transmission side main controller 100 ₀ When the analog data s1 obtained by the D / A converter 102 is converted into digital data by the A / D converter 201 of the receiving side sub-controller 200 using ₀ Since the value is lower than the original value, there is a state where it cannot be converted into correct digital data. However, in the configuration of the present embodiment, the reference voltage V from the main controller 100 on the transmission side with respect to the sub controller 200 on the reception side. ₁ The CPU circuit 202 converts the digital data obtained by the conversion by the A / D converter 201 into the reference voltage V ₁ Is corrected as an error canceling voltage to cancel errors caused by ambient temperature characteristics or the like, thereby obtaining correct digital data.
[0021]
Next, referring to the flowchart of FIG. 4, a method for canceling an error caused by transmission of the analog data s1 between the controllers executed by the sub-controller 200, and a configuration of the means for executing the canceling method (error canceling device) are described. explain. Here, in order to clarify the quantitative relationship, values in each part are defined. In FIG. 3, the digital value of the engine speed data output from the CPU circuit 101 on the transmission side is a, the analog data s1 value obtained by the D / A conversion of the D / A converter 102 is b, and the partial pressure The voltage dividing ratio of the circuit 104 is c, and the value of the reference voltage output from the voltage dividing circuit 104 is V. ₁ The resolution of the D / A converter 102 is 8 bits. The digital value of the engine speed data obtained by the A / D conversion of the A / D converter 201 on the receiving side and input to the CPU circuit 202 is obtained by d, and similarly obtained by the conversion of the A / D converter 201 on the receiving side. The reference voltage V input to the CPU circuit 202 ₁ The digital value of e is A and the resolution of the A / D converter 201 is 8 bits.
[0022]
Reference voltage V on the receiving side ₀ Varies depending on the ambient temperature characteristics, etc. ₀ It is assumed that the value is ′. Normal V ₀ 'Is the reference voltage value V ₀ To a smaller value. In the sub controller 200 on the receiving side, the reference voltage output from the reference voltage source 203 due to the ambient temperature characteristics or the like does not match the reference voltage of the reference voltage source 103 on the transmitting side. When the analog data s1 is A / D converted in 201, an error is included. In other words, the digital value d of the engine speed output from the A / D converter 201 of the secondary controller 200 is a control system composed of two controllers 100 and 200, and the engine from the main controller 100 to the secondary controller 200. A transmission error caused by transmitting the rotation speed information in the form of analog data s1 using D / A conversion or A / D conversion is included. An error canceling device realized by a program in the CPU circuit 202 cancels the transmission error by the following method and generates correct engine speed data.
[0023]
First, a relational expression related to D / A conversion in the main controller 100 on the transmission side is shown. ₀ And b = V between the digital value a of the engine speed and the value b of the analog data s1. ₀ / 256 × a (Expression 1) and reference voltage V ₀ And voltage division ratio c and reference voltage V ₁ V between ₁ = V ₀ / C (Expression 2)
[0024]
On the other hand, in the sub controller 200 on the receiving side, the analog data s1 (value b) and the reference voltage V ₁ Are respectively converted into digital values d and e by the A / D converter 201. Analog data s1 (value b), corresponding digital value d, reference voltage V ₁ And the corresponding digital value e, reference voltage V ₀ ′ Has the following relationship.
[0025]
[Expression 1]
d = b / V ₀ ′ × 256 (Formula 3)
e = V ₁ / V ₀ ′ × 256 (Formula 4)
[0026]
The CPU circuit 202 inputs the digital values d and e via the bus line 204. Step S11 shown in FIG. 4 is a step of taking in the digital values d and e sent from the A / D converter 201. A voltage division ratio c is stored in advance in a ROM (not shown) of the CPU circuit 201. Therefore, the partial pressure ratio c is taken out from the ROM (step S12). Step S13 is a calculation process (ratio conversion process) for canceling a transmission error included in the transmission data transmitted as the analog data s1, and calculating correct engine speed data. That is, the correct engine speed data can be obtained by the transmission data calculation value = d × 256 / (e × c) (Equation 5). Thus, the reference voltage (value V) output from the reference voltage source 103 on the transmission side is obtained by the transmission error canceling method realized in steps S11 to S13. ₀ ) And the reference voltage (value V) output from the reference voltage source 203 on the receiving side ₀ Even if a different state occurs, the digital value a of the engine speed data output from the CPU circuit 101 matches the calculated transmission data value.
[0027]
However, although the transmission error is 0 in the calculation, the quantization error of the D / A converter 102 and the A / D converter 201 and the voltage division error of the voltage dividing circuit 104 remain, so that the digital value a and the transmission data are calculated. There will be an error between the values. However, the error is very small as compared with the case where the process using the reference voltage as a reference is not performed.
[0028]
In the above embodiment, the reason why the reference voltage output from the reference voltage source 103 is divided as the reference voltage is that fluctuations in the reference voltage on the receiving side occur in a decreasing direction. In a normal design, for example, 3/4 voltage division is performed by the voltage dividing circuit 104.
[0029]
FIG. 5 is a diagram illustrating an example of specific contents of analog data transmitted between controls. In this example, the original reference voltage V ₀ Is 100 V (volts), while the reference voltage on the receiving side shown on the right side of the figure is V ₀ 'Shows a state where the voltage drops to 90V. As shown in the figure, the engine speed (rpm) is such that, for example, 2000 rpm corresponds to 100 V (100%), and 1000 rpm corresponds to 50 V (50%). Here, when the digital data a represents 1000 rpm, that is, when the digital data a is 50 V (50%) on the transmission side, the digital data a is converted into analog data s1 by the D / A converter 102, and the arrow 30 Thus, the digital data obtained by the conversion by the A / D converter 201 of the sub controller 200 is about 55.5 V (about 55.5%) because the reference voltage is 90 V. Therefore, if the cancel method of the present embodiment is not executed, the information on the engine speed is transmitted to the sub controller 200 as about 1111 r.pm.
[0030]
However, in the case of this embodiment, as described above, the reference voltage V ₁ That is, for example, 25 V divided by a voltage dividing ratio of 3/4 is transmitted in the same manner, and is obtained as a value of about 27 V by the A / D converter 201. Therefore, by using this value and comparing with the reference voltage 25V stored in the storage unit of the CPU circuit 202, the fluctuation of the reference voltage on the receiving side is calculated by the above ratio conversion processing, and the above 55.5V is calculated. It can be recalculated to the first correct value of 50V.
[0033]
In the above embodiment, the description is limited to the hydraulic excavator, but it is needless to say that the present invention can be applied to other construction machines having the same configuration and operating environment. Further, as an example, the relationship between the two controllers, the main controller 100 and the sub-controller 200, has been described. However, the number of controllers is not limited to two, and even when the control system is configured by a larger number of controllers. It is the same.
[0034]
【The invention's effect】
As is apparent from the above description, according to the present invention, in a construction machine such as a hydraulic excavator equipped with an electronic control system, the electronic control system is a control system including at least two digital controllers, and data transmission between the controllers is performed. Is configured to send the voltage to cancel the transmission error from the transmitter controller to the receiver controller, the transmission controller can always cancel the transmission error. You can always get the right data. In particular, when the receiving-side controller is a dedicated controller for controlling the fuel injection amount of a diesel engine, it is possible to accurately obtain information on the engine speed from the transmitting-side controller, and to control the appropriate fuel injection amount. It can be carried out. Also, the voltage for canceling the transmission error is generated by dividing the reference voltage from the reference voltage source provided in the controller on the transmission side to create a smaller value. It is particularly convenient from the viewpoint of changing in a decreasing direction, and a normal operating state can always be maintained. Furthermore, according to the configuration in which the error canceling voltage is received by the receiving side controller, there is an advantage that it is convenient in the subsequent failure analysis when the transmission line is disconnected.
[Brief description of the drawings]
FIG. 1 is an example of a construction machine and is a side view of a hydraulic excavator provided with two controllers.
FIG. 2 is a configuration diagram of a control system including two controllers.
FIG. 3 is an electric circuit diagram showing the configuration of the first embodiment.
FIG. 4 is a flowchart for implementing a method of canceling an error at a receiving controller resulting from the transmission of analog data between controllers.
FIG. 5 is a diagram illustrating an example of specific contents of analog data transmitted between controls.
[Explanation of symbols]
15 cab
17 Working device
18 Machine room
19 Diesel engine
100 Main controller
200 Secondary controller
24 Transmission path (cable)

Claims (8)

A construction machine includes a first controller including a digital processing unit and a D / A conversion unit, and a second controller including a digital processing unit and an A / D conversion unit, and the D / A conversion unit of the first controller Configured to transmit analog data to the A / D converter of the second controller;
A first reference voltage source for supplying a reference voltage to the D / A converter in the first controller; a second reference voltage source for supplying a reference voltage to the A / D converter in the second controller;
An error canceling voltage is transmitted from the first reference voltage source to the digital processing unit of the second controller through the A / D converter, and the digital processing unit outputs the reference output from the first reference voltage source. An analog data transmission between controllers of a construction machine, wherein a transmission error of the analog data caused by a difference between a voltage and the reference voltage output from the second reference voltage source is canceled by the error canceling voltage. Error cancellation method. The second controller is a device that controls the fuel injection amount of the diesel engine, and the first controller is a device that sends engine speed information necessary for controlling the fuel injection amount of the diesel engine as the analog data. An error canceling method for analog data transmission between controllers of a construction machine according to claim 1. 3. The error canceling method for analog data transmission between controllers of a construction machine according to claim 1, wherein the error canceling voltage is obtained by dividing the reference voltage output from the first reference voltage source. 4. The digital processing unit of the second controller performs a ratio conversion process on the analog data using a ratio of the error cancel voltage, and calculates a correct ratio of the analog data. An error canceling method for analog data transmission between controllers of the described construction machine. A first controller including a digital processing unit and a D / A conversion unit and a second controller including a digital processing unit and an A / D conversion unit are mounted, and from the D / A conversion unit of the first controller to the second controller A construction machine configured to transmit analog data to the D / A converter of
A first reference voltage source for supplying a reference voltage to the D / A converter in the first controller; a second reference voltage source for supplying a reference voltage to the A / D converter in the second controller;
A circuit for sending an error cancellation voltage from the first reference voltage source to the A / D converter in the first controller;
The digital processing unit of the second controller transmits the analog data due to a difference between the reference voltage output from the first reference voltage source and the reference voltage output from the second reference voltage source. An error canceling device for analog data transmission between controllers of a construction machine, comprising canceling means for canceling an error with the error canceling voltage. The second controller is a device that controls the fuel injection amount of the diesel engine, and the first controller is a device that sends engine speed information necessary for controlling the fuel injection amount of the diesel engine as the analog data. 6. An error canceling device for analog data transmission between controllers of a construction machine according to claim 5. 7. The error canceling apparatus for analog data transmission between controllers of a construction machine according to claim 5, wherein the circuit for sending the error canceling voltage is a voltage dividing circuit. 8. The controller of a construction machine according to claim 7, wherein the canceling unit performs a ratio conversion process on the analog data by using a ratio of the error canceling voltage, and calculates a correct ratio of the analog data. An error canceling device for analog data transmission.

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