Omron CQM1H-SCB41 Operation Manual page 132

Overview of NT Links
3. The Programming Console functions of the PT (Expansion Mode) cannot
be used when connected to Serial Communications Board ports. They can
be used only by connecting to the peripheral port or RS-232C port on the
CPU Unit. This is true in both 1:1 and 1:N mode.
4. When using 1:N-mode NT Links, set a unique unit number for each PT
connected to the same PC. If the same unit number is set for more than
one PT, malfunctions will occur.
5. The number of PTs that can be connected to one port in 1:N mode is lim-
ited by the CPU Unit's cycle time when a Serial Communications Board is
used, as shown in the following diagrams. Although some communications
will be possible even if these restrictions are exceeded, communications
errors will occur depending on the PT operating conditions and communi-
cations load. Always abide by these restrictions when using 1:N mode.
Example for NT31/NT631(C) PTs
Priority
Registered
PTs per port
Priority Not
Registered
PTs per port
CPU Unit's cycle time (ms)
CPU Unit's cycle time (ms)
Section 8-1
117