Automation Direct D2-DCM, User Manual

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Introduction
5 5
Data Communications Module, 2nd Edition, 2/03
Applications
The D2–DCM can be used as a network interface for applications that require data to
be shared between PLCs, or between PLCs and an intelligent device (such as a host
computer). The D2–DCM can be configured as either a master or slave station and
allows you to upload or download virtually any type of system data including
Timer/Counter data, I/O information, and V-memory information.
Request
Direct NET Slaves
Slaves respond to the master’s request
Response
PC or D2–DCM
master can
communicate with
Direct NET Slaves
Direct NET Masters
Issue requests to slave stations
Using a D2–DCM as a Network Master
The DL205 D2–DCM can be used with a
D2–240/250–1/260 CPU to serve as a
network master. Your CPU must have
firmware V1.8 or later.
It cannot be used
with a DL230 CPU. (A master is the
network station that initiates requests for
data from other stations on the network).
You simply use special RLL instructions (RX
and WX) inside of your RLL program to
initiate the data exchange. The D2–DCM
takes communication requests issued by
the PLC program instructions and
automatically converts these requests into
network commands that read data from or
write data to another network station.
Possible Slaves
D D2–240/250–1/260 CPU (bottom
port)
D
D2–240/250–1/260 w/ D2–DCM
D
D3–330 or D3–330P w/ DCU
D
D3–340 (either port)
D
D4–430 (bottom port)
D
D4–440 (bottom port)
D
D4–450 (phone jack or bottom port)
D
Any DL405 CPU w/ D4–DCM
The PLC program is really very simple and only requires a few instructions. Appendix
A provides an overview of the instructions. Or, see the
Direct NET Manual for network
details.
Using a D2–DCM as a Network Slave
The D2–DCM can also be used with a
D2–240/250–1/260 CPU to serve as a
network slave station.
It cannot be used
with a DL230 CPU. In this case, the
D2–DCM “listens” to the network for any
messages that contain the D2–DCM’s
address. The D2–DCM deciphers the
network commands, carries out the
request to read or write data, and sends
confirmation and/or information to the
master station.
Possible Masters
D
D2–240/250–1/260
w/ D2–DCM
D
D3–340 CPU (bottom port)
D Any DL405 CPU w/ D4–DCM
D
D4–450 CPU (bottom port)
D
Host computer w/ Direct SOFT
DSData Server
As a Direct NET
Interface