Safety Considerations Guide for Trident v2 Systems - TUV ...

68 Appendix A Triconex Peer-to-Peer Communication
Examples of Peer-to-Peer Applications
Triconex Peer-to-Peer function blocks are designed to transfer limited amounts of data between
two applications. Therefore, you should use these function blocks sparingly in your
applications.
Ideally, you should control the execution of each SEND function block so that each SEND is
initiated only when the acknowledgment for the last SEND is received and new data is available
for sending. You can do this through effective use of the SENDFLG parameter in the SEND
function block and the STATUS output of the SEND function block, as shown in Examples 3 and
4.
The examples described in this section can be found in the Tdpeer.pt2 project included as part
of the TriStation 1131 software installation.
Example 1: Fast Send to One Triconex Node
This example shows how to send data as fast as possible from node #2 to node #3. Scan time in
both controllers is set to 100 milliseconds.
The example uses the following project elements:
• PEER_EX1_SEND_FBD (for sending node #2)
• PEER_EX1_RCV_FBD (for receiving node #3)
Example 2: Sending Data Every Second to One Node
This example shows how to send data every second from node #2 to node #3. Scan time in both
controllers is set to 100 milliseconds.
The example uses the following project elements:
• PEER_EX2_SEND_FBD (for sending node #2)
• PEER_EX2_RCV_FBD (for receiving node #3)
Example 3: Controlled Use of SEND/RECEIVE Function Blocks
This example shows how to use SEND/RECEIVE function blocks correctly, in a controlled way,
so that a limited amount of important data can be transferred between two applications when
new data is ready to be sent.
This example uses the following project elements:
• PEER_EX3_SEND_FBD (for sending node #2)
• PEER_EX3_RCV_FBD (for receiving node #3)
Safety Considerations Guide for Trident v2 Systems