FDX-08 Command Guide
14
2.2.4
Limit on the number of TCP-IP connections and port overload management
The FDX’s maintenance port supports a maximum of eight simultaneous connections (eight logical ports).
To maintain optimal system accessibility, it is advisable to issue “port-open” and “port-close” commands
before and after command or query strings are issued. This approach enables eight or more control devices to
be effectively interfaced simultaneously and without concern for communication errors.
[Table 2.3] Increasing connections
Your PC software
FDX-08
TCP-IP connection
→
(1 port occupied)
Send command (@xxx)
→
←
The command (@xxx) replied
TCP-IP close
→
(1 port released)
Note:
If no command is sent from the PC side to the FDX for 30 seconds, the FDX automatically disconnects from
that device. As a result, connection needs to be established again from the PC side after connection of the PC
is disconnected. (Since the number of ports in the FDX is eight, ports are occupied permanently if the PC is
turned off while connections are valid. To prevent this, the FDX disconnects connections if no communication
command is sent from the PC side.)
