Hardy HI 6600 Series Modular Sensor System - Manual (Page 54)

HI 6600 Series Modular Sensor System User Guide
Page | 54
The EIP diagnostic parameters count the number of packets of various types received (in) or transmitted
(out).
TCP in 24
TCP out 22
UDP out 9
UDP in 9
UDP IO in 0
UDP IO out 0
PCCC in 0
PCCC out 0
TCP is used for most explicit or unconnected messages. The usual sort of EtherNet/IP connection is one in which packets
are sent and received at some specified RPI (requested packet interval). These packets are sent and received via UDP and
show up in the "UDP IO" count variables. It takes a few TCP packets to set up this connection, and these packets show up
in the TCP counters.
Finally, there are some older PLCs like the SLC and PLC-5 that lack a full implementation of EtherNet/IP, and cannot
support a cyclic connection. These PLCs sometimes use an older protocol called PCCC, and the PCCC variables count
the number of PCCC messages received or sent.