阅读说明：本技术 飞机加油方法、系统、无线呆德曼以及可读存储介质 (Airplane refueling method and system, wireless deadman and readable storage medium ) 是由 杨军 尹波 董建 刘伟锋 骆德亮 何仲能 李辉 冯彧超 于 2020-12-23 设计创作，主要内容包括：本申请公开了一种飞机加油方法、系统、无线呆德曼以及可读存储介质,该飞机加油方法包括：响应于用户的第一输入指令,选择输入指令对应的控制器编号,并与控制器编号对应的控制器建立通信连接；响应于用户的第二输入指令,向控制器发送控制指令,以使控制器按照控制指令控制气动阀门的工作状态。上述方案,实现无线控制加油车给飞机加油的方式,使得加油操作人员可以在离加油车较远的距离进行加油。(The application discloses an aircraft refueling method, an aircraft refueling system, a wireless Dadaman and a readable storage medium, wherein the aircraft refueling method comprises the following steps: responding to a first input instruction of a user, selecting a controller number corresponding to the input instruction, and establishing communication connection with a controller corresponding to the controller number; and responding to a second input command of the user, and sending a control command to the controller so that the controller controls the working state of the pneumatic valve according to the control command. Above-mentioned scheme realizes the mode that wireless control tank service truck refueled the aircraft for refuel operating personnel can refuel at the distance far away from the tank service truck.)

1. An aircraft refueling method is characterized by being applied to a wireless deadman, wherein the wireless deadman is in communication connection with a controller installed on a refueling truck, the controller is connected with a pneumatic valve of the refueling truck, and the pneumatic valve is connected with a cylinder of an aircraft;

the aircraft refueling method comprises the following steps:

responding to a first input instruction of a user, selecting a controller number corresponding to the input instruction, and establishing communication connection with a controller corresponding to the controller number;

and responding to a second input command of the user, and sending a control command to the controller so that the controller controls the working state of the pneumatic valve according to the control command.

2. A method of refuelling an aircraft according to claim 1,

the step of establishing communication connection with the controller corresponding to the controller number includes:

sending a connection request signal to a controller corresponding to the controller number, wherein the connection request signal comprises a device code of the wireless modem;

receiving a reply message returned by the controller corresponding to the controller number, wherein the reply message comprises a connection password corresponding to the equipment code;

and establishing communication connection with the controller corresponding to the controller number according to the connection password.

3. A method of refuelling an aircraft according to claim 2,

the first input instruction is a controller number on a single-click display interface;

before the step of selecting the controller number corresponding to the input command in response to the first input command of the user, the aircraft refueling method further includes:

initializing the display interface;

searching all controllers within a communication range;

and displaying the searched controller codes of the controllers on the display interface.

4. A method of refuelling an aircraft according to claim 1,

the second input instruction is to press a switch of the wireless Dadaman;

the aircraft refueling method comprises the following steps:

and sending a control command for starting oiling to the controller in response to a second input command of the user so as to enable the controller to start the pneumatic valve.

5. A method of refuelling an aircraft according to claim 4,

the aircraft refueling method further comprises:

sending a control command to stop refueling to the controller to cause the controller to close the pneumatic valve in response to a third input command from the user;

wherein the third input instruction is to release the wireless Dadaman switch.

6. A method of refuelling an aircraft according to claim 4,

the aircraft refueling method further comprises:

judging whether the duration time of the second input instruction is greater than a preset time threshold value or not;

if so, sending a control instruction for starting oiling to the controller so as to enable the controller to start the pneumatic valve;

and if not, confirming that the second input instruction is misoperation.

7. A method of refuelling an aircraft according to claim 1,

the second input instruction is to close the switch of the wireless Dadaman;

the aircraft refueling method comprises the following steps:

sending a control command to the controller to initiate fueling in response to a second input command by the user to cause the controller to initiate the pneumatic valve;

judging whether a continuous refueling function is triggered or not within a preset period;

if not, sending a control instruction of stopping oiling to the controller so that the controller closes the pneumatic valve.

8. A method of refueling an aircraft as defined in claim 7,

before the step of sending a control command to the controller to stop refueling, the aircraft refueling method further comprises:

and before the preset period is finished, displaying a warning lamp for prompting and/or starting a warning buzzer.

9. A method of refuelling an aircraft according to claim 1,

the aircraft refueling method further comprises:

receiving refueling information returned by the controller;

and displaying the refueling information on a display interface.

10. An aircraft refueling system characterized in that it comprises at least:

the refueling truck is provided with a pneumatic valve for connecting an oil cylinder of the airplane;

the controller is arranged on the refueling truck and connected with a pneumatic valve of the refueling truck;

the wireless Dadman is in communication connection with the controller;

the wireless Dadman is used for responding to a first input instruction of a user, selecting a controller number corresponding to the input instruction, and establishing communication connection with a controller corresponding to the controller number;

the wireless Dadman is further used for responding to a second input instruction of the user and sending a control instruction to the controller;

and the controller is used for controlling the working state of the pneumatic valve according to the control command.

11. A wireless deadman, comprising a memory and a processor coupled to each other, the processor being configured to execute program instructions stored in the memory to implement the aircraft refueling method of any one of claims 1 to 9.

12. A computer readable storage medium having stored thereon program instructions, which when executed by a processor, carry out a method of refuelling an aircraft according to any of claims 1 to 9.

Technical Field

The application relates to the technical field of intelligent oiling control, in particular to an aircraft oiling method, an aircraft oiling system, a wireless deadman and a readable storage medium.

Background

The aviation gas station undertakes the oil supply guarantee task of the flight taking off and landing on the airport apron, and the basic oil filling operation flow is as follows: the dispatcher obtains the takeoff oil quantity of each flight of the airline company by means of telephone and the like and informs the aircraft refueler through the interphone; or the unit and the crew affairs input the takeoff oil quantity on the airplane oil quantity control panel; or the aircraft refueling personnel arrive at the site to inquire the unit and the crew personnel to obtain the takeoff oil quantity of the aircraft; an airplane refueling operator receives a refueling instruction which is issued by a dispatcher and contains a flight number, a machine position, a takeoff oil quantity and the like through automatic printing oil list equipment (MDT), and performs refueling operation on a designated airplane on a apron. In the process of airplane refueling operation, an airplane refueling operator controls the refueling amount by using a hand-held pneumatic control valve dead man (DEADMN), and when an oil-controlled system of an airplane reaches a set value of the takeoff oil amount, an oil way is automatically cut off, and refueling is stopped.

Because the aircraft refueling personnel need to hold the pneumatic control valve to control the refueling amount by a dead man, the range of motion of the aircraft refueling personnel is limited, the work of other aspects cannot be well considered, and other work details can be ignored in the refueling process.

Disclosure of Invention

The application at least provides an aircraft refueling method, an aircraft refueling system, a wireless Dadaman and a readable storage medium.

The first aspect of the application provides an aircraft refueling method, which is applied to a wireless deadman, wherein the wireless deadman is in communication connection with a controller installed on a refueling truck, the controller is connected with a pneumatic valve of the refueling truck, and the pneumatic valve is connected with a cylinder of an aircraft;

the aircraft refueling method comprises the following steps:

responding to a first input instruction of a user, selecting a controller number corresponding to the input instruction, and establishing communication connection with a controller corresponding to the controller number;

and responding to a second input command of the user, and sending a control command to the controller so that the controller controls the working state of the pneumatic valve according to the control command.

In some embodiments, the step of establishing a communication connection with the controller corresponding to the controller number includes:

sending a connection request signal to a controller corresponding to the controller number, wherein the connection request signal comprises a device code of the wireless modem;

receiving a reply message returned by the controller corresponding to the controller number, wherein the reply message comprises a connection password corresponding to the equipment code;

and establishing communication connection with the controller corresponding to the controller number according to the connection password.

In some embodiments, the first input instruction is a single click of a controller number on a display interface;

before the step of selecting the controller number corresponding to the input command in response to the first input command of the user, the aircraft refueling method further includes:

initializing the display interface;

searching all controllers within a communication range;

and displaying the searched controller codes of the controllers on the display interface.

In some embodiments, the second input instruction is to press a switch of the wireless dumman;

the aircraft refueling method comprises the following steps:

and sending a control command for starting oiling to the controller in response to a second input command of the user so as to enable the controller to start the pneumatic valve.

In some embodiments, the aircraft refueling method further comprises:

sending a control command to stop refueling to the controller to cause the controller to close the pneumatic valve in response to a third input command from the user;

wherein the third input instruction is to release the wireless Dadaman switch.

In some embodiments, the aircraft refueling method further comprises:

judging whether the duration time of the second input instruction is greater than a preset time threshold value or not;

if so, sending a control instruction for starting oiling to the controller so as to enable the controller to start the pneumatic valve;

and if not, confirming that the second input instruction is misoperation.

In some embodiments, the second input instruction is to close the wireless dumman switch;

the aircraft refueling method comprises the following steps:

sending a control command to the controller to initiate fueling in response to a second input command by the user to cause the controller to initiate the pneumatic valve;

judging whether a continuous refueling function is triggered or not within a preset period;

if not, sending a control instruction of stopping oiling to the controller so that the controller closes the pneumatic valve.

In some embodiments, prior to the step of sending a control command to the controller to stop fueling, the method of fueling an aircraft further comprises:

and before the preset period is finished, displaying a warning lamp for prompting and/or starting a warning buzzer.

In some embodiments, the aircraft refueling method further comprises:

receiving refueling information returned by the controller;

and displaying the refueling information on a display interface.

A second aspect of the present application provides an aircraft refuelling system comprising at least:

the refueling truck is provided with a pneumatic valve for connecting an oil cylinder of the airplane;

the controller is arranged on the refueling truck and connected with a pneumatic valve of the refueling truck;

the wireless Dadman is in communication connection with the controller;

the wireless Dadman is used for responding to a first input instruction of a user, selecting a controller number corresponding to the input instruction, and establishing communication connection with a controller corresponding to the controller number;

the wireless Dadman is further used for responding to a second input instruction of the user and sending a control instruction to the controller;

and the controller is used for controlling the working state of the pneumatic valve according to the control command.

A third aspect of the present application provides a wireless dumman, comprising a memory and a processor coupled to each other, wherein the processor is configured to execute program instructions stored in the memory to implement the aircraft refueling method of the first aspect.

A fourth aspect of the present application provides a computer readable storage medium having stored thereon program instructions which, when executed by a processor, implement the method of refuelling an aircraft of the first aspect described above.

According to the scheme, the wireless Dadaman responds to a first input instruction of a user, selects a controller number corresponding to the input instruction, and establishes communication connection with a controller corresponding to the controller number; and responding to a second input command of the user, and sending a control command to the controller so that the controller controls the working state of the pneumatic valve according to the control command. Above-mentioned scheme realizes the mode that wireless control tank service truck refueled the aircraft for refuel operating personnel can refuel at the distance far away from the tank service truck.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

FIG. 1 is a schematic flow chart diagram illustrating one embodiment of a method for fueling an aircraft as provided herein;

FIG. 2 is a detailed flowchart of the sub-step of step S11 shown in FIG. 1;

FIG. 3 is a block diagram of an embodiment of an aircraft fueling system provided herein;

FIG. 4 is a block diagram of an embodiment of a wireless Dadaman provided herein;

FIG. 5 is a block diagram of another embodiment of the wireless Dadaman provided herein;

FIG. 6 is a block diagram of an embodiment of a computer-readable storage medium provided herein.

Detailed Description

The following describes in detail the embodiments of the present application with reference to the drawings attached hereto.

In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular system structures, interfaces, techniques, etc. in order to provide a thorough understanding of the present application.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship. Further, the term "plurality" herein means two or more than two. In addition, the term "at least one" herein means any one of a plurality or any combination of at least two of a plurality, for example, including at least one of A, B, C, and may mean including any one or more elements selected from the group consisting of A, B and C.

Referring specifically to fig. 1, fig. 1 is a schematic flow chart of an embodiment of an aircraft refueling method provided in the present application. The execution main body of the aircraft refueling method disclosed by the embodiment of the disclosure can be a wireless Dadaman.

Advantages of the wireless dumman of the disclosed embodiments include, but are not limited to: the wireless operation distance can reach 30 meters, and the operation range can be adjusted in the receiver; the integrated system comprises all the dead man safety operations; a plurality of DELTA wireless systems can operate in the same area without interfering with each other; the wireless operation improves the operation efficiency and the safety, the length of a wireless cable is limited when the wireless cable moves around the refueling equipment, and a brake cable is not needed; no risk of false activation, each wireless handheld device has a unique code; the system is flexible and modularized, and the operation and maintenance are convenient; a timer is arranged in the handheld device, and an operator can operate the handheld device without risk; the timer warning lamp and the buzzer are integrally output; an external rewrite function; comprehensive interlocking is realized, and safe operation is ensured; the battery has long capacity, and can be used for more than 12 hours when fully charged; an intelligent charger is arranged in the receiver; and a unique coding system between the handheld device and the receiver is easy to maintain.

Specifically, based on the wireless dumman, the aircraft refueling method of the embodiment of the present disclosure may include the following steps:

step S11: responding to a first input instruction of a user, selecting a controller number corresponding to the input instruction, and establishing communication connection with a controller corresponding to the controller number.

Before the airplane refueling method disclosed by the embodiment of the disclosure is executed, a refueling operator needs to start the wireless deadman, so that the wireless deadman initializes a display interface on a display and initializes a communication function.

After the wireless deadman starts the communication function, all controllers in the communication range are searched, and accordingly, the refueling operator needs to open the communication function of the controllers.

It should be noted that the wireless dumman and the controller in the embodiments of the present disclosure may be in communication connection through wireless transmission technologies such as bluetooth and infrared. The wireless Dadman is stably connected with the controller in 30 meters, the operation range can be adjusted in the controller, and the wireless Dadman has good anti-interference and interference suppression functions. The connection is kept stable under the complex communication environment shielded by objects such as air park radio waves, radar waves, metal and the like.

The controller of the embodiment of the disclosure is a universal product of both DC12V and DC24V aviation fuelling vehicles, is a modular system, and has later-stage function expansion. The operation and maintenance are convenient, the design structure principle is advanced, the performance is stable and reliable, the operation is simple and convenient, the power consumption is small, the shock resistance is good, the shell dissipates heat, prevents drenching, and the mechanical strength is good.

The wireless Dadman battery of the embodiment of the disclosure has the advantages of long capacity, advanced design structure principle, stable and reliable performance, simple and convenient operation and low power consumption. Industrial grade shell, IP67 protection security level, it is good to prevent falling the shock resistance, and mechanical strength is good, long service life. The battery has a charging function, the standby endurance time exceeds 48 hours, the working time exceeds 8 hours, and the equipment normally operates within the range of-10 ℃ to 60 ℃.

The controller can continuously broadcast own controller codes through wireless transmission, and the searched controller codes are displayed on a display interface by the wireless Dadaman so that a refueling operator can view the connectable controller.

The refueling operator clicks the controller number on a display interface of the wireless Dadaman and inputs a first input instruction to the wireless Dadaman, so that the controller to be controlled and the corresponding refueling truck are selected, and the wireless Dadaman is in communication connection with the controller. Referring to fig. 2, fig. 2 is a flowchart illustrating a sub-step of step S11 shown in fig. 1.

Specifically, step S11 includes the following substeps:

step S111: and sending a connection request signal to a controller corresponding to the controller number, wherein the connection request signal comprises a wireless Darman device code.

The wireless deadman sends a connection request signal to the controller corresponding to the controller number selected by the refueling operator, wherein the connection request signal includes a device code of the wireless deadman. Due to the application scene in the airport, a plurality of wireless dummies work in the same area, and each wireless dummies has a unique equipment code, so that mutual interference can be avoided, and the risk of false activation is avoided.

Step S112: and receiving a reply message returned by the controller corresponding to the controller number, wherein the reply message comprises a connection password corresponding to the equipment code.

After receiving the wireless Darman connection request signal, the controller checks the validity of the wireless Darman device code. And after the verification is passed, replying a reply message to the wireless Ideman, wherein the reply message should comprise a connection password corresponding to the equipment code, and the connection password can be a matching code used for establishing communication connection.

Step S113: and establishing communication connection with the controller corresponding to the controller number according to the connection password.

The wireless deadman displays the connection password replied by the controller on the display interface, and the refueling operator confirms the controller to be controlled again, so that the connection password can be confirmed, and the wireless deadman establishes communication connection with the controller.

Step S12: and responding to a second input command of the user, and sending a control command to the controller so that the controller controls the working state of the pneumatic valve according to the control command.

After the wireless deadman is successfully connected with the controller, an oiling operator can control the controller through a hardware structure on the wireless deadman or an operation button on a display interface, so that the effect of wirelessly controlling the oiling vehicle is achieved.

Specifically, in one approach, the second input command from the fueling operator is to press a wireless deadman switch. Wireless staying deman is provided with the function of protection mechanism, refuels operating personnel and need continuously press wireless staying deman's switch and just can keep the fuel filling, prevents to refuel in-process personnel's error, has the function that can stop the operation loose hand.

When an oiling operator presses a switch of the wireless deadman, the wireless deadman sends a control instruction for starting oiling to the controller, so that the controller starts the pneumatic valve, and the oiling vehicle starts oiling to the airplane.

When the refueling operator loosens the switch of the wireless deadman, the wireless deadman sends a control instruction for stopping refueling to the controller, so that the controller closes the pneumatic valve, and the refueling truck stops refueling the airplane.

Through above-mentioned wireless transmission mode, wireless slow-witted demann can realize the work that wireless control refueled the vehicle and refuel to the aircraft, refuels operating personnel and can hand wireless slow-witted demann activity and be in the distance far away from the refueled vehicle.

In the above control method, in order to reduce the probability of the fueling operator performing an erroneous operation. The wireless Dadman also supports a misoperation detection function, and the specific process is as follows: judging whether the duration of the second input instruction, namely the duration of pressing the wireless Dadaman switch by the refueling operator is greater than a preset time threshold value; if so, sending a control instruction for starting oiling to the controller so as to enable the controller to start the pneumatic valve; if not, the second input instruction is confirmed to be misoperation.

In another mode, the second input instruction of the refueling operator is to close a wireless deadman switch or click a control button on the display interface. The wireless Dadman has the periodic timing continuous oiling function, the continuous oiling function is not triggered within three minutes, the warning lamp prompts in advance for ten seconds, and oiling is stopped immediately by the time.

When the oiling operator closes the switch of the wireless deadman or clicks the control button on the display interface, the wireless deadman sends a control instruction for starting oiling to the controller, so that the controller starts the pneumatic valve.

Then, in a preset period, such as three minutes, wirelessly and constantly judging whether to trigger the continuous refueling function; if not, sending a control instruction of stopping oiling to the controller so that the controller closes the pneumatic valve.

Further, before the preset period is finished, for example, ten seconds ahead, the wireless Dadman displays a warning lamp for prompting and/or starts a warning buzzer.

In the above-mentioned complete aircraft refueling in-process, wireless slow-witted demann can also receive the refueling information that the controller returned according to the cycle to on will refueling information show display interface, in order to supply to refuel operating personnel can in time look over the condition of refueling. Specifically, fueling information includes, but is not limited to: the number of refuels, the number of refuels target, the speed of refuelling etc.

In the embodiment of the disclosure, the wireless Dadman selects the controller number corresponding to the input instruction by responding to the first input instruction of the user, and establishes communication connection with the controller corresponding to the controller number; and responding to a second input command of the user, and sending a control command to the controller so that the controller controls the working state of the pneumatic valve according to the control command. Above-mentioned scheme realizes the mode that wireless control tank service truck refueled the aircraft for refuel operating personnel can refuel at the distance far away from the tank service truck.

It will be understood by those skilled in the art that in the method of the present invention, the order of writing the steps does not imply a strict order of execution and any limitations on the implementation, and the specific order of execution of the steps should be determined by their function and possible inherent logic.

With continuing reference to fig. 3, fig. 3 is a schematic diagram of an embodiment of an aircraft fueling system according to the present application. As shown in fig. 3, an aircraft fueling system 30 of an embodiment of the present disclosure includes at least:

the fuelling vehicle 31 is provided with a pneumatic valve (not shown) for connection to an aircraft cylinder.

And a controller 32 provided in the fueling vehicle 31 and connected to the air-operated valve of the fueling vehicle 31.

And the wireless modem 33 is in communication connection with the controller 32.

Specifically, the wireless modem 33 is configured to select, in response to a first input instruction of the user, a controller number corresponding to the input instruction, and establish a communication connection with the controller 32 corresponding to the controller number. A wireless modem 33, further configured to send a control instruction to the controller 32 in response to a second input instruction from the user; and the controller 32 is used for controlling the working state of the pneumatic valve according to the control command.

Referring to fig. 4, fig. 4 is a schematic diagram of a wireless dumman according to an embodiment of the present disclosure. Wireless dumman 40 includes a communication module 41 and a control module 42.

The communication module 41 is configured to, in response to a first input instruction of a user, select a controller number corresponding to the input instruction, and establish a communication connection with a controller corresponding to the controller number; and the control module 42 is used for responding to a second input command of the user and sending a control command to the controller so that the controller controls the working state of the pneumatic valve according to the control command.

Referring to fig. 5, fig. 5 is a schematic diagram of a wireless dumman according to another embodiment of the present disclosure. Wireless fideman 50 includes a memory 51 and a processor 52 coupled to each other, processor 52 being configured to execute program instructions stored in memory 51 to implement the steps of any of the above-described embodiments of the aircraft fueling method. In one particular implementation scenario, wireless dumman 50 may include, but is not limited to: the microcomputer and the server, and in addition, the wireless dumman 50 may further include a mobile device such as a notebook computer, a tablet computer, and the like, which is not limited herein.

In particular, processor 52 is configured to control itself and memory 51 to implement the steps of any of the aircraft fueling method embodiments described above. Processor 52 may also be referred to as a CPU (Central Processing Unit). Processor 52 may be an integrated circuit chip having signal processing capabilities. The Processor 52 may also be a general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. In addition, the processor 52 may be commonly implemented by an integrated circuit chip.

Referring to fig. 6, fig. 6 is a block diagram illustrating an embodiment of a computer-readable storage medium according to the present application. Computer readable storage medium 60 stores program instructions 601 capable of being executed by a processor, program instructions 601 for implementing the steps of any of the aircraft refueling method embodiments described above.

In some embodiments, functions of or modules included in the apparatus provided in the embodiments of the present disclosure may be used to execute the method described in the above method embodiments, and specific implementation thereof may refer to the description of the above method embodiments, and for brevity, will not be described again here.

The foregoing description of the various embodiments is intended to highlight various differences between the embodiments, and the same or similar parts may be referred to each other, and for brevity, will not be described again herein.

In the several embodiments provided in the present application, it should be understood that the disclosed method and apparatus may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, a division of a module or a unit is merely one type of logical division, and an actual implementation may have another division, for example, a unit or a component may be combined or integrated with another system, or some features may be omitted, or not implemented. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or units through some interfaces, and may be in an electrical, mechanical or other form.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed to by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, a network device, or the like) or a processor (processor) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.