Rockwell Automation 1785-LTx,D17856.2.1 Classic PLC-5 Programmable Controllers Users Manual - Manual (Page 19)

Understanding Your System
Chapter 1
1-9
Use a Classic PLC-5 processor (except the PLC-5/10 processor) in adapter
mode when you need predictable, real-time exchange of data between a
distributed control PLC-5 processor and a supervisory processor. You
connect the processors via the remote I/O link (see Figure 1.3). You can
monitor status between the supervisory processor and the adapter-mode
PLC-5 processor at a consistent rate (i.e., the transmission rate of the
remote I/O link is unaffected by programming terminals and other
non-control-related communications).
Figure 1.3
AdapterĆMode Communication
1
Remote I/O Link
1771 I/O
DL40
Message
Display
Remote I/O Link
Supervisory
Processor
PLCĆ5
Processor
in Adapter
Mode
1 The following programmable controllers can operate as supervisory processors:
PLCĆ2/20t and PLCĆ2/30t processors
PLCĆ3t and PLCĆ3/10t processors
PLCĆ5/11, Ć5/15, Ć5/20, Ć5/25, and Ć5/30 processors as well as PLCĆ5/VMEt processors
PLCĆ5/40, Ć5/40L, Ć5/60, Ć5/60L, and Ć5/80 processors as well as PLCĆ5/40BVt and
PLCĆ5/40LVt processors
PLCĆ5/20Et, Ć5/40Et
PLCĆ5/250t
All PLCĆ5 family processors, except the PLCĆ5/10, can operate as remote I/O adapter modules.
2
2
The PLC-5 processor in adapter mode acts as a remote station to the
supervisory processor. The adapter-mode PLC-5 processor can monitor
and control its processor-resident local I/O while communicating with the
supervisory processor via a remote I/O link.
The supervisory processor communicates with the PLC-5/12, -5/15, or
-5/25 adapter with either eight or four I/O image table words.
A PLC-5 processor transfers I/O data and status data using discrete
transfers and block transfers. You can also use block-transfer instructions
to communicate information between a supervisory processor and an
adapter-mode processor. The maximum capacity per block transfer is
64 words.
Using the Classic PLCĆ5
Processor
as a Remote I/O Adapter