CONTROLLER, CONTROL SYSTEM, AND CONTROL METHOD

• US 20150304193A1
• Filed: 04/02/2013
• Published: 10/22/2015
• Est. Priority Date: 04/18/2012
• Status: Active Grant

• Current Assignee: Yokogawa Electric Corporation
• Original Assignee: Yokogawa Electric Corporation
• Inventors: ISHII, Yousuke, YAMAJI, Masato, TAKEKAWA, Masahiro
• Granted Patent: US 10,187,279 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G05B 19/4185 characterised by the network communication
• CPC Class Codes: G05B 2219/33192 Radio link, wireless
• CPC Class Codes: G05B 2219/40151 Time delay, problems caused by time delay between local and remote
• CPC Class Codes: H04L 43/0852 Delays
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route
• CPC Class Codes: H04L 67/125 involving control of end-device applications over a network
• CPC Class Codes: H04L 67/62 Establishing a time schedule for servicing the requests

Abstract

A controller for using a first data item transmitted via a network to generate a second data item for controlling an entity to be controlled over the network, wherein the controller is characterized in being provided with: an adjustment unit for adjusting, with respect to the maximum delay time permissible on the network, the time by which generation of the second data item is started using the first data item after the first data item has been received; and a delay compensation unit, designed using a model of the entity to be controlled and the maximum delay time permissible on the network, for compensating for the delay of the first and second data items that can be generated using the network.

Claims

1. A control device that uses first data, transmitted thereto via a network, to generate second data for controlling a controlled object via the network, comprising:

an adjustment unit that considers a maximum delay time tolerated by the network, and adjusts a time from a reception of the first data until a start of generating the second data using the first data; and

a delay compensation unit that is designed using a model of the controlled object and the maximum delay time tolerated by the network, and compensates delays in the first and second data that can occur in the network.

2. The control device according to claim 1, wherein

the first data contains first time information indicating a time at which the first data was generated or transmitted, and

the adjustment unit adjusts a timing so that the second data is started to be generated at a timing when a period of time, which is obtained by subtracting a difference between a time indicated by the first time information and a time at which the first data was received from the maximum delay time tolerated by the network, has elapsed from a point at which the first data was received.

3. A control system that controls a controlled object via a network, comprising:

a control device that uses first data, transmitted thereto via a network, to generate second data for controlling a controlled object via the network, the control device including;

an adjustment unit that considers a maximum delay time tolerated by the network, and adjusts a time from a reception of the first data until a start of generating the second data using the first data; and

a delay compensation unit that is designed using a model of the controlled object and the maximum delay time tolerated by the network, and compensates delays in the first and second data that can occur in the network; and

a field device having a timing adjustment unit that considers the maximum delay time tolerated by the network, and adjusts a timing of a manipulation of the controlled object based on the second data transmitted from the control device.

4. The control system according to claim 3, wherein

the first data contains first time information indicating a time at which the first data was generated or transmitted, and

the adjustment unit adjusts a timing so that the second data is started to be generated at a timing when a period of time, which is obtained by subtracting a difference between a time indicated by the first time information and a time at which the first data was received from the maximum delay time tolerated by the network, has elapsed from a point at which the first data was received.

5. The control system according to claim 3, wherein

the second data contains second time information indicating a time at which the second data was transmitted, and

the timing adjustment unit adjusts a timing so that a manipulation of the controlled object is performed at a timing when a period of time, which is obtained by subtracting a difference between a time indicated by the second time information and a time at which the second data was received from the maximum delay time tolerated by the network, has elapsed from a point at which the second data was received.

6. The control system according to claim 3, wherein the maximum delay time tolerated by the network includes:

a first maximum delay time tolerated for data transmitted to the control device; and

a second maximum delay time tolerated for data transmitted from the control device.

7. The control system according to claim 3, further comprising:

a management device that sets the maximum delay time tolerated by the network with respect to the control device and the field devices.

8. The control system according to claim 3, wherein

the timing adjustment unit adjusts a timing so that a manipulation is performed when a period of time Tx, shown in Equation (1) below, has elapsed from time t12 when the second data was received at the field device,

Tx=Td−

(t12−

t11)  

 

(1)

where Td is the maximum delay time tolerated by the network, t11 is a time at which the second data was transmitted from the control device, and t12 is a time at which the second data was received at the field device.

9. The control system according to claim 3, wherein

the adjustment unit adjusts a timing so that a setting-value is generated when a period of time Ty, shown in Equation (2) below, has elapsed since time t22 when the first data was received at the control device,

Ty=Td−

(t22−

t21)  

 

(2)

where Td is the maximum delay time tolerated by the network, t21 is a time at which the first data is generated at or transmitted from the field device, and t22 is a time at which the first data is received at the control device.

10. The control system according to claim 3, further comprising:

a setting-value generator that uses the first data from the field device to generate a setting-value for controlling the controlled object, at a timing adjusted by the adjustment unit.

11. The control system according to claim 3, wherein

the delay compensation unit is designed using a model element that is a model of a fluid motion characteristic of a fluid which is the controlled object, and a delay element where the maximum delay times tolerated by the network are set, in addition to a controller, and

the delay compensation unit compensates error between the fluid motion characteristic of the fluid which is the controlled object and the model element, by feeding back a difference ‘

Y-Y’

′

between present measurement data ‘

Y’

measured by the field device and data ‘

Y’

′

output from the delay element of the delay compensation unit.

12. A control method that uses first data, transmitted thereto via a network, to generate second data for controlling a controlled object via the network, comprising:

considering a maximum delay time tolerated by the network, and adjusting a time from a reception of the first data until a start of generating the second data using the first data; and

compensating delays in the first and second data that can occur in the network by using a model of the controlled object and the maximum delay time tolerated by the network.

13. The control method according to claim 12, wherein

the first data contains first time information indicating a time at which the first data was generated or transmitted, and

the control method further comprising adjusting a time so that the second data is started to be generated at a timing when a period of time, which is obtained by subtracting a difference between a time indicated by the first time information and a time at which the first data was received from the maximum delay time tolerated by the network, has elapsed from a point at which the first data was received.

14. The control method according to claim 12, further comprising:

considering the maximum delay time tolerated by the network, and adjusting a timing of a manipulation of the controlled object based on the second data transmitted from the control device.

15. The control method according to claim 12, wherein:

the second data contains second time information indicating a time at which the second data was transmitted, and

the control method further comprising adjusting a timing so that a manipulation of the controlled object is performed at a timing when a period of time, which is obtained by subtracting a difference between a time indicated by the second time information and a time at which the second data was received from the maximum delay time tolerated by the network, has elapsed from a point at which the second data was received.

16. The control method according to claim 12, wherein the maximum delay time tolerated by the network includes:

a first maximum delay time tolerated for data transmitted to the control device; and

a second maximum delay time tolerated for data transmitted from the control device.

17. The control method according to claim 12, further comprising:

adjusting a timing so that a manipulation is performed when a period of time Tx, shown in Equation (1) below, has elapsed from time t12 when the second data was received,

Tx=Td−

(t12−

t11)  

 

(1)

where Td is the maximum delay time tolerated by the network, t11 is a time at which the second data was transmitted, and t12 is a time at which the second data was received.

18. The control method according to claim 12, further comprising:

adjusting a timing so that a setting-value is generated when a period of time Ty, shown in Equation (2) below, has elapsed since time t22 when the first data was received,

Ty=Td−

(t22−

t21)  

 

(2)

where Td is the maximum delay time tolerated by the network, t21 is a time at which the first data is generated at or transmitted, and t22 is a time at which the first data is received.