Method of detecting response time-out based on master-slave protocol

1. A response time-out detection method based on master-slave protocol architecture, which calculates the time required for a detection device functioning as a Modbus master to receive a response from a slave device in response to a Modbus request sent by the detection device based on Modbus communication protocol, the method comprising the steps of:

(a) start detection;

(b) said detection device sends a Modbus return query data function and subfunction code to said slave device, and records a request sent time;

(c) said slave device receives the Modbus return query data function and subfunction code sent by said detection device;

(d) said slave device determines whether or not to support the return query data function, and then proceeds to step (e) if yes, or step (f) if not;

(e) said slave device executes the return query data function and sends an accurate result response, and then proceeds to step (g);

(f) said slave device sends an exception response and then proceeds to step (g);

(g) said detection device receives the accurate/exception response from said slave device and records a response received time;

(h) calculate the response time-out based on said request sent time and said response received time;

(i) determine whether or not to run a next detection and return to step (b) if yes, or proceed to step (j) if not;

(j) calculate the precise response time-out from said response time-outs which are gotten from said slave device in response to a predetermined number of the Modbus requests; and

(k) end the detection;

wherein said master-slave communications architecture is one of Modbus RTU and Modbus ASCII.

2. The response time-out detection method based on master-slave protocol architecture as claimed in claim 1 , wherein the calculation of the precise responding time is done by obtaining one of the average time, maximum time and shortest time of the response time-out by means of a function.

3. The response time-out detection method based on master-slave protocol architecture as claimed in claim 2 , wherein the calculation of said precise response time-out includes the step of adding a time delay.

4. The response time-out detection method based on master-slave protocol architecture as claimed in claim 1 , wherein the calculation of the response time-out is done by means of the equation of RS M =TR M −TS M , in which RS M is the respond time-out; TR M is the time point at which said detection device received the respond from said slave device; TS M is the time point at which said detection device sent the request to said slave device.

5. The response time-out detection method based on master-slave protocol architecture as claimed in claim 2 , wherein obtaining the average time for the precise response time-out is done by means of a calculation through the equation of:

RS

F

=

Fn

⁡

(

RS

1

,

RS

2

,

…

⁢

,

RS

N

+

1

)

=

∑

M

=

1

N

+

1

⁢

RS

M

(

N

+

1

)

,

in which: Fn ( ) is a function; RS F is the precise response time-out of said slave device; RS 1 , . . . , RS N+1 are response time-out during the period.

6. The response time-out detection method based on master-slave protocol architecture as claimed in claim 2 , wherein obtaining the maximum time of the precise response time-out is done by means of a calculation through the equation of:

RS

F

=

Fn

⁡

(

RS

1

,

RS

2

,

…

⁢

,

RS

N

+

1

)

=

MAX

⁡

(

RS

1

,

RS

2

,

…

⁢

,

RS

N

+

1

)

,

in which: Fn ( ) is a function; RS F is the precise response time-out of said slave device; RS 1 , RS 2 , . . . , RS N+1 are response time-out during the period.

7. The response time-out detection method based on master-slave protocol architecture as claimed in claim 1 , wherein said precise response time-out is applicable to the formal communication period between said master device and said slave device.

8. The response time-out detection method based on master-slave protocol architecture as claimed in claim 1 , wherein said precise response time-out is applicable to the formal communication time period among a communication gateway, said slave device, and a remote device.

9. The response time-out detection method based on master-slave protocol architecture as claimed in claim 1 , wherein said detection device is one of a Modbus master device, a Modbus communication gateway, and an independent device having detection device function.

10. A response time-out detection method based on master-slave protocol architecture, which calculates the time required for a detection device functioning as a Modbus master to receive a response from a slave device in response to a Modbus request sent by the detection device based on Modbus communication protocol, the method comprising the step of:

(a) start detection;

(b) said detection device sends a Modbus read function code to said slave device, and records a request sent time;

(c) said slave device receives the Modbus read function code sent by said detection device;

(d) said slave device determines whether or not to support the read function, and then proceeds to step (e) if yes, or step (f) if not;

(e) said slave device executes the read function and sends an accurate result response, and then proceeds to step (g);

(f) said slave device sends a exception response and then proceeds to step (g);

(g) said detection device receives the accurate/exception response from said slave device and records the received time;

(h) calculate the response time-out based on said request sent time and said response received time;

(i) determine whether or not to run a next detection and return to step (b) if yes, or proceeds to step (j) if not;

(j) calculate the precise response time-out from said response time-outs which are gotten from said salve device in response to a predetermined number of the MODBUS requests; and

(k) end the detection;

wherein said master-slave communications architecture is one of Modbus RTU and Modbus ASCII.

11. The response time-out detection method based on master-slave protocol architecture as claimed in claim 10 , wherein the calculation of the precise responding time is done by obtaining one of the average time, maximum time and shortest time of the response time-out by means of a function.

12. The response time-out detection method based on master-slave protocol architecture as claimed in claim 11 , wherein the calculation of said precise response time-out includes the step of adding a time delay.

13. The response time-out detection method based on master-slave protocol architecture as claimed in claim 10 , wherein the calculation of the response time-out is done by means of the equation of RS M =TR M −TS M , in which RS M is the respond time-out; TR M is the time point at which said detection device received the response from said slave device; TS M is the time point at which said detection device sent the request to said slave device.

14. The response time-out detection method based on master-slave protocol architecture as claimed in claim 11 , wherein obtaining the average time for the precise response time-out is done by means of a calculation through the equation of:

RS

F

=

Fn

⁡

(

RS

1

,

RS

2

,

…

⁢

,

RS

N

+

1

)

=

∑

M

=

1

N

+

1

⁢

RS

M

(

N

+

1

)

,

in which: Fn ( ) is a function; RS F is the precise response time-out of said slave device; RS 1 , . . . , RS N+1 are response time-out during the period.

15. The response time-out detection method based on master-slave protocol architecture as claimed in claim 11 , wherein obtaining the maximum time of the precise response time-out is done by means of a calculation through the equation of:

RS

F

=

Fn

⁡

(

RS

1

,

RS

2

,

…

⁢

,

RS

N

+

1

)

=

MAX

⁡

(

RS

1

,

RS

2

,

…

⁢

,

RS

N

+

1

)

,

in which: Fn ( ) is a function; RS F is the precise response time-out of said slave device; RS 1 , RS 2 , . . . , RS N+1 are response time-out during the period.

16. The response time-out detection method based on master-slave protocol architecture as claimed in claim 10 , wherein said precise response time-out is applicable to the formal communication period between said master device and said slave device.

17. The response time-out detection method based on master-slave protocol architecture as claimed in claim 10 , wherein said precise response time-out is applicable to the formal communication time period among a communication gateway, said slave device, and a remote device.

18. The response time-out detection method based on master-slave protocol architecture as claimed in claim 10 , wherein said detection device is one of Modbus master device, Modbus communication gateway, and independent device having detection device function.

19. The response time-out detection method based on master-slave protocol architecture as claimed in claim 10 , wherein said read function code is one of a read coils function code, a read discrete inputs function code, a read holding registers function code, and a read input register function code.