"The MicroLogix 1400 supports a maximum of 32 EtherNet/IP connections and
32 Modbus TCP connections, allowing a maximum of 32 outgoing and a
maximum of 32 incoming simultaneous connections with up to 64 other devices
or applications..."
Explicit messaging is by nature an unconnected data exchange (not counting against any limits); the user could choose a 'connected' state for said data transfer at configuration time if the application requires it though; the latter scenario will count against the maximum number of established connections.