Connections

Section 8-1

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 con- nected 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 limited 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 communications load. Always abide by these restrictions when using 1:N mode.

Example for NT31/NT631(C) PTs

Priority

Registered

PTs per port

CPU Unit’s cycle time (ms)

Priority Not

Registered

PTs per port

CPU Unit’s cycle time (ms)

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