ProSoft Technology MVI71-GEC - Manual (Page 65)

MVI71-GEC ♦ PLC 5 Platform Reference
Generic ASCII Ethernet Communication Module User Manual
ProSoft Technology, Inc. Page 65 of 86
May 11, 2011
Each server has a state value in the status data area. This value is utilized by the
ladder logic to determine if a connection is present on server. The following table
defines the state status values used by each server:
State Value Definition
-1 Server is initializing and is being set up to listen.
0 The server is waiting for a client to establish a connection.
1 The server has established a connection with a client and can send or receive
data.
1000 The server has initiated a close operation on the connection.
1001 The server is waiting for the close on the connection to complete.
1002 The server is issuing an abort (reset) on the connection. The socket is forced
closed.
3000 The client is issuing the ARP command request and waiting for the response.
3001 The client has received the ARP response and has opened the socket.
Ladder logic should only direct messages to servers that have a state status
value of 1. The module will ignore all messages sent to servers with any other
state value.
When the ladder logic sends a message to a server, it can request that the
socket be closed after the message is sent. The server control word in the output
image is used for this purpose. Place a value of 1 in this register to gently close
the connection after the message is sent. If a value of 2 is placed in the register,
the server will abort the connection to force the socket closed (send a message
with the Reset Flag set to the client). Most applications will have the client close
the socket.