Add a Serial Remote I/O Master/Slave Module
In addition to the I/O located in the local base, adding remote I/O can be accomplished via a
shielded twisted-pair cable linking the master CPU to a remote I/O base. The methods of
adding serial remote I/O are:
• DL240 CPUs: Remote I/O requires a remote master module (D2–RMSM) to be installed in the
local base. The CPU updates the remote master, then the remote master handles all communication
to and from the remote I/O base by communicating to a remote slave module (D2–RSSS) installed
in each remote base.
• DL250–1 and D2–260 CPU: The CPU’s comm port 2 features a built-in Remote I/O channel. You
may also use up to 7 D2–RMSM remote masters in the local base as described above (you can use
either or both methods).
Remote I/O points map into different CPU memory locations, therefore it does not reduce
the number of local I/O points. Refer to the DL205 Remote I/O manual for details on
remote I/O configuration and numbering. Configuring the built-in remote I/O channel is
described in the following section.
The figure below shows one CPU base, and one remote I/O channel with six remote bases. If
the CPU is a DL250–1 or DL260, adding the first remote I/O channel does not require
installing a remote master module (use the CPU’s built-in remote I/O channel).
DL205 User Manual, 4th Edition, Rev. B
4–26
Chapter 4: System Design and Configuration
1
2
3
4
5
6
7
8
9
10
11
12
13
14
A
B
C
D
DL230 DL240 DL250–1 DL260
Maximum number of Remote Masters supported in the local
CPU base (1 channel per Remote Master)
none
2
7
7
CPU built-in Remote I/O channels
none
none
1
1
Maximum I/O points supported by each channel
none
2048
2048
2048
Maximum Remote I/O points supported
none
Limited by total references available
Maximum number of remote I/O bases per channel(RM–NET)
none
7
7
7
Maximum number of remote I/O bases per channel (SM–NET)
none
31
31
31
230
2
4
0
2
5
0
-1
2
6
0
ý
þ
þ
þ
Remote Slaves
Maximum of
7 remote bases
per channel
Remote Masters
Masters can go in any slot except next to CPU.
Allowable distance is from farthest slave to the remote master.
Maximum of:
7 per CPU base (DL250-1 & DL260)
(for DL250-1 & DL260 the bottom port of
the CPU can serve as an eighth master)
2 per CPU base (DL240)
