Safety network system and safety slave

• US 20040210620A1
• Filed: 06/07/2004
• Published: 10/21/2004
• Est. Priority Date: 06/22/2001
• Status: Active Grant

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Nakamura, Toshiyuki, Muneta, Yasuo
• Granted Patent: US 7,472,106 B2
• Time in Patent Office: Days
• US Class Current: 709/200
• CPC Class Codes: G05B 19/05 Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts
• CPC Class Codes: G05B 2219/14012 Safety integrity level, safety integrated systems, SIL, SIS
• CPC Class Codes: G05B 2219/24137 Non volatile memory to store program on power loss
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing

Abstract

A safety PLC 1 serving as a master and a safety slave 2 are connected through a safety network 3 to constitute a network system. The safety slave has non-safety information storing unit 26 for storing individual information and a state information of the connected safety device, the state information monitors a state of the operating safety device and a stored content is updated based on its monitored result. Then, when the non-safety information satisfying a fixed condition, at least the non-safety information satisfied the condition is transmitted to the safety PLC. That processing is performed by an MPU 23. Thus, unnecessary non-safety information is not transmitted.

Claims

1. A safety slave connectable to a safety network characterized by comprising:

a safety information transmitting function of transmitting safety information determining a safety state or not, corresponding to a demand transmitted from a safety controller through the safety network;

non-safety information storing means for storing non-safety information about the safety slave; and

a function of transmitting at least the non-safety information which satisfies a fixed condition to the safety controller when the non-safety information stored in the non-safety information storing means satisfies the fixed condition.

3. The safety slave according to claim 1, characterized in that transmission of the non-safety information is performed in one communication cycle based on the demand after other safety slaves finish the safety responses.

4. A network system comprising a safety controller and a safety slave according to claim 1, which are connected through a safety network, characterized in that information of the device output from the slave is transmitted to the controller.

5. The safety network system according to claim 4, characterized in that one communication cycle managed by the safety controller has a reception period for non-safety information after reception of a safety response from the safety slave.

2. A safety slave connectable to a safety network characterized by comprising:

a safety information transmitting function of transmitting safety information determining a safety state or not, corresponding to a demand transmitted from a safety controller through the safety network;

non-safety information storing means for storing non-safety information about the safety slave;

storing means for storing a condition for transmitting the non-safety information;

monitoring means for determining whether the non-safety information stored in the non-safety information satisfies the condition or not; and

determining means for determining a transmission timing based on a monitored result of the monitoring means.

6. A safety slave connectable to a safety network characterized by comprising:

a safety information transmitting function of transmitting safety information determining a safety state or not, corresponding to a demand transmitted from another node through the safety network;

non-safety information storing means for storing non-safety information about the safety slave; and

a function of transmitting at least the non-safety information which satisfies a fixed condition to the other node when the non-safety information stored in the non-safety information storing means satisfies the fixed condition.

7. A safety slave connectable to a safety network characterized by comprising:

a safety information transmitting function of transmitting safety information determining a safety state or not, when a transmission condition is satisfied;

non-safety information storing means for storing non-safety information about the safety slave; and

a function of transmitting at least the non-safety information which satisfies a fixed condition to the other node connected to the safety network when the non-safety information stored in the non-safety information storing means satisfies the fixed condition.