Rockwell Automation 1785-L20C_L40C, D17856.5.14 ControlNet PLC-5 Programmable Controllers User Manual User Manual

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Chapter 2

Planning to Use Your ControlNet

PLCĆ5 Processor

2-5

Features

Description

Operation

①

Because connections are opened and closed as needed, more can exist in a program as long as no more than this number are active at one time.

Using I/O Forcing Operations

ControlNet I/O forcing occurs in the same way as remote I/O forcing in
the PLC-5/20 and -5/40 processors. The processor performs the forcing
and transmits the forced data to the output- and input-image tables. You
can force any discrete I/O data placed in the I/O image; however, forcing
of non-discrete I/O data is not supported.

For detailed information on forcing, see PLC-5 Programming Software
Configuration and Maintenance, publication 6200-6.4.6.

Using Immediate DataĆTransfer Operations

ControlNet Immediate Data I/O transfers—Immediate Data Input (IDI)
and Immediate Data Output (IDO)—perform similarly to the remote-I/O
supported immediate I/O transfers—Immediate Input (INN) and
Immediate Output (IOT)—which the ControlNet system also supports.
The logic scan is temporarily interrupted while the most recent state of
one discrete input or output word is read from or written to the private
memory buffer.