Publication 1766-RM001A-EN-P - October 2008
500
Socket Interface Using CIP Generic Messaging
Read
The Read service reads data on a socket. You can specify a number of
bytes to receive. The Read service returns the number of bytes received.
For TCP, the Read service returns when any data is received, up to the
requested number of bytes. The Read service can return fewer bytes than
were requested. Your application might need to issue multiple Read
requests to receive an entire application message.
For UDP, the Read service completes when a datagram is available
MSG Configuration Parameters
To call this service, click "Setup Screen" in the MSG instruction and enter
the values displayed below.
Parameter
Value
Service Type
Read
Service Code
4D (hexadecimal)
Class
342 (hexadecimal)
Instance
0. Use a relay ladder instruction to move the returned
instance number from a CreateSocket service into the
MGx:y.TFN element of a MSG instruction
Attribute
0
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