Case 2: Connect Com Port 1 to other devices that support the Modbus TCP
(client/server) protocol via a switch or hub.
NOTE: Com Port 1 can communicate with any number of servers (slaves) using the Receive and/or Send
instructions. However, Com Port 1 can communicate with up to 4 servers at the same time. If the ladder
program has sent a message to 4 different servers and tries to send a message to another server, the
CLICK PLC unit disconnects the ο¬rst server and establishes a connection with the new server, maintaining
a total of 4 servers.
NOTE: Com Port 1 can communicate with up to 3 clients (masters). If a client attempts to establish
communication with Com Port 1 while it is communicating with 3 clients, the CLICK PLC unit replies with
an error to the forth client.
CLICK PLC Hardware User Manual, 6th Edition, Rev. F β C0-USER-M
4β18
Chapter 4: PLC Communications