Rockwell Automation 1771-KA2 Communication Adapter Module - Manual (Page 19)

Station Hardware
Chapter 2
2-9
The interaction between a KA2 module and its station processor occurs in
memory control. The station KA2 can read data from and write data into
processor memory, based on various user-programmed commands.
Commands that originate at a station communication adapter module can
control only data table areas of processor memory. Commands generated
by a computer that is connected to the Data Highway through a
communication controller module (cat. no. 1771-KE/KF) can control
both data table and user program memory areas.
Note that the processor continues to execute the user program and to
control output devices, whether or not the station communication adapter
module is in operation. Thus, disconnection of the Data Highway cable or
faulted operation of the communication adapter module does not cause
shutdown of the station processor.
A-B designed the 1771-KA2 module to fit in a Bulletin 1771 I/O chassis
assembly (cat. no. 1771-A1,-A2,-A4). This chassis houses Mini-PLC-2,
Mini-PLC-2/05 and Mini-PLC-2/15 programmable controllers. With one
of these controllers, you can use any unoccupied I/O slot for
communication adapter modules.
With PLC-2/20 and PLC-2/30 programmable controllers, use a Bulletin
1771 I/O chassis as an I/O rack. In this case, the 1771-KA2 module can
be installed in any chassis slot except the one furthest left. This left-most
slot must be occupied by a PLC-2 I/O adapter module (cat. no. 1771-AL
or 1771-AS), shown in Figure 2.6, or a backplane jumper board assembly
(cat. no. 1771-EY).
A Bulletin 1771 I/O chassis is usually mounted within an enclosure. We
recommend proper grounding of this enclosure because it minimizes the
effect of noise from the surrounding industrial environment. (Grounding
procedures for the Bulletin 1771 I/O chassis are described in publication
1772-6.6.3).
I/O Chassis