Remote terminal industrial control communication system
First Claim
1. An industrial control system comprising:
- a communication network over which messages are exchanged between devices connected to the network, wherein each message contains a source address indicating the device from which the message originated and a destination address;
a central processor which executes a control program to operate equipment connected to the industrial control system;
means for coupling said central processor to said communication network for the exchange of messages over the network; and
a plurality of remote terminal units for exchanging messages with said central processor, each of said remote terminal units comprising;
a) means, coupled to said communication network, for receiving messages,b) means for storing a first address and a second address,c) a first means for comparing the first address to the destination address contained in a message received from said communication network and producing a first indicia that the addresses are the same,d) a second means for comparing the second address to the source address contained in the message received from said communication network and producing a second indicia that the addresses compared by said second means are the same,e) means for responding to the received message in response to the presence of both the first and second indicia, andf) an interface for exchanging control data with the equipment, an exchange of data being in response to said means for responding to the received message.
1 Assignment
0 Petitions
Accused Products
Abstract
An industrial control system has a central processing unit and a plurality of remote terminal units coupled to a communication network. Data is exchanged among the network devices in the form of messages which contain a source address, which designates the network address of the device that sent the message, and a destination address. Each of the remote terminal units stores a first network address assigned to the unit, and second network address corresponding to the network address of the originator of messages to which the remote terminal unit is to respond. The remote terminal unit processes only those messages in which both the destination address matches the first network address and the source address in the message matches the second network address. Thus multiple devices can be assigned the same first network address as long as each such device responds to a different source address. This enables more devices to be coupled to the network than the maximum number of allowable network addresses. Similarly multiple central processing units can be coupled to the network with access to a given remote terminal unit being restricted by the second address to messages originating from only one of the central processing units.
210 Citations
12 Claims
-
1. An industrial control system comprising:
-
a communication network over which messages are exchanged between devices connected to the network, wherein each message contains a source address indicating the device from which the message originated and a destination address; a central processor which executes a control program to operate equipment connected to the industrial control system; means for coupling said central processor to said communication network for the exchange of messages over the network; and a plurality of remote terminal units for exchanging messages with said central processor, each of said remote terminal units comprising; a) means, coupled to said communication network, for receiving messages, b) means for storing a first address and a second address, c) a first means for comparing the first address to the destination address contained in a message received from said communication network and producing a first indicia that the addresses are the same, d) a second means for comparing the second address to the source address contained in the message received from said communication network and producing a second indicia that the addresses compared by said second means are the same, e) means for responding to the received message in response to the presence of both the first and second indicia, and f) an interface for exchanging control data with the equipment, an exchange of data being in response to said means for responding to the received message. - View Dependent Claims (2, 3)
-
-
4. An industrial control system comprising:
-
a communication network over which messages are exchanged between devices connected to the network with each device being assigned a network address, wherein each message contains a source address indicating the device from which the message originated and a destination address; a plurality of central processors each of which including means, coupled to said communication network, for the exchange of messages over the network, each of said central processors being assigned a unique address on said communication network; and a plurality of remote terminal units for exchanging messages with said central processor, each of said remote terminal units comprising; a) means, coupled to said communication network, for receiving messages, b) means for storing a first address and a second address; c) a first means for comparing the first address to the destination address contained in a message received from said communication network and producing a first indicia that the compared addresses are the same, d) a second means for comparing the second address to the source address contained in the message received from said communication network and producing a second indicia that the addresses compared by said second means are the same, and e) means for responding to the received message in response to the presence of both the first and second indicia. - View Dependent Claims (5)
-
-
6. A remote terminal unit, for an industrial control system that includes a communication network for the exchange of messages in which each message contains a destination address and a source address, a central processor which executes a control program to operate equipment connected to the industrial control system and which is coupled to the communication network, wherein the remote terminal unit comprises:
-
means, coupled to said communication network, for receiving messages from the central processor; means for storing a first address and a second address; a first means for comparing the first address to the destination address contained in a message received from said communication network and producing a first indicia that the compared addresses are the same; a second means for comparing the second address to the source address contained in the message received from said communication network and producing a second indicia that the addresses compared by said second means are the same; and means for responding to the received message in response to the presence of both the first and second indicia. - View Dependent Claims (7, 8, 9, 10, 11, 12)
-
Specification