CTI 2572-A, Installation And Operation Manual

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CTI 2572-A Installation and Operation Guide V1.3 59
The S
OURCE
E
LEMENT
specifies the 505 PLC Tag Name. We want to read a 16 bit unsigned integer
into a 32 bit signed Control Logix tag, so we will use the tag type VE. Since we want to start reading
at V memory location 501, the complete Tag Name is VE501.
We want to read a block of 100 registers, so the N
UMBER OF
E
LEMENTS
will be set to 100.
The D
ESTINATION
E
LEMENT
specifies the Control Logix tag that will store the results of the read
message. This is the tag we defined earlier. Since this is an array, we will specify that first value
returned will be stored in array element 0. Additional values will be stored in subsequent array
elements.
Communication Tab
The Communication Tab is used to specify the message routing and destination IP address.
The path specifies the route from the controller to the destination. In this case, we will send the
message to the backplane (1), to the Ethernet module located in slot 3, out the Ethernet port (2), to the
2572-A module whose IP address is 192.184.177.225.
The C
ACHE
C
ONNECTIONS
box is checked to keep the TCP connection established after the message
is completed. If you don’t check this box, the Control Logix will close the TCP connection after each
message transaction is complete. Continually opening and closing the TCP connection adds
unnecessary overhead and reduces performance.