ProSoft Technology MVI56-GEC - Manual (Page 78)

Reference MVI56-GEC ♦ ControlLogix Platform
User Manual Generic ASCII Ethernet Communication Module
Page 78 of 108 ProSoft Technology, Inc.
October 8, 2010
Up to 400 bytes of data can be sent in each block starting at word offset 3 in the
block. If the message to be sent to a server is longer than 400 bytes, multiple
blocks are required. If more than 400 bytes are required to send, the message
length field (Word Offset 2) should be set to a value of -1 and 400 bytes of data
should be placed in the block. When 400 or fewer bytes remain to be sent, the
message length field should be set to that value and the remaining data placed in
the block. The client or server will accept messages up to a length of 8192 bytes.
If a message longer than 8192 bytes is sent to a server, a transmit overflow error
will be recorded and the message will be sent when 8192 bytes are received.
The remaining part of the message will be sent as it is received.
Word offsets 203 and 212 request a new connection for one of the five clients in
the module. The format of this data area is shown in the following table.
Word Description
203 Client to utilized for connection (10 to 14)
204 Reserved for future use.
205 to 208 IP address of server to which connection will be made. Each word contains one of
the digits of a dotted notation IP address.
209 Service port in server to which connection will be made. This service must be
available in the server for the connection to succeed.
210 Swap Rx data bytes (0 = No, not 0 = Yes)
211 Swap Tx data bytes (0 = No, not 0 = Yes)
212 Client TimeOut value in milliseconds. The client will close the connection with remote
Server after the specified milliseconds once data transfer ceases between the client
and the remote Server. A value of 0 will keep the connection open indefinitely.
Ladder logic is required to transfer this data to the block when a connection is
required. The ladder logic should also clear the area after the connection is
requested. The example ladder logic present in this document presents code to
accomplish these tasks.