Logix5000 Controllers General Instructions - SLAC Confluence

186 Input/Output Instructions (MSG, GSV, SSV, IOT)Access The MESSAGE ObjectYou can access the MESSAGE object through the GSV/SSVinstructions. Specify the message tag name to determine whichMESSAGE object you want. The MESSAGE object provides aninterface to setup and trigger peer-to-peer communications. Thisobject replaces the MG data type of the PLC-5 processor.Attribute Data Type Instruction DescriptionConnectionPath SINT[130] GSVData to setup the connection path. The first two bytes (low byteand high byte) are the length in bytes of the connection path.SSVConnectionRate DINT GSVRequested packet rate of the connection.SSVMessageType SINT GSVSSVPort SINT GSVSSVTimeoutMultiplier SINT GSVSSVUnconnectedTimeout DINT GSVSSVSpecifies the type of message.Value: Meaning:0 not initializedIndicates which port the message should be sent on.Value: Meaning:1 backplane2 serial portDetermines when a connection should be considered timed outand closed.Value: Meaning:0 connection will timeout in 4 times the update rate(default)1 connection will timeout in 8 times the update rate2 connection will timeout in 16 times the update rateTimeout period in microseconds for all unconnected messages. Thedefault is 30,000,000 microseconds (30 seconds).To change a MESSAGE attribute, follow these steps:1. Use a GSV instruction to get the MessageType attribute and saveit in a tag.2. Use a SSV instruction to set the MessageType to 0.3. Use a SSV instruction to set the MESSAGE attribute that you wantto change.4. Use a SSV instruction to set the MessageType attribute back tothe original value you obtained in step 1.Publication 1756-RM003I-EN-P - January 2007