4
Creating Project Files—PLC to Devices
12
Siemens Energy & Automation, Inc.
4 Creating Project Files—PLC to
Devices
This chapter covers configuration of the DTU3005 for PLC
communications with Siemens devices. Once you have cre-
ated a PLC to Devices project (see
Chapter 3
), follow the
directions in this chapter to configure the project file. Then
see
Chapter 7
for directions on downloading the project to
the DTU3005. See also
Appendix D
for wiring diagrams for
your particular PLC, as required.
4.1
Application Description
The PLC to Devices application allows a PLC to control and
monitor up to 32 SEAbus devices or Siemens protective
relays. In this application, the DTU3005B initiates all com-
munications with both the PLC and the Siemens devices.
The DTU3005B uses an internal transfer table to transfer
data to the PLC. The transfer table contains a block of
selected real-time data parameters obtained from a device.
The DTU3005B unit acts as a master to the PLC, and con-
tinuously transfers the table data to the selected block of
registers on the PLC. A delay option is provided for each
device’s table entry to prevent unnecessarily slowing down
the scan time of the PLC as well as to give some device
data transfers higher priority than others.
No ladder logic is required on the PLC to use the basic fea-
ture of this application, which allows a limited amount of
information to be transferred between the PLC and the
devices. Ladder logic programming is required to use the
command block function. The command block is used to
send commands to the devices, such as operating or
releasing relays, or resetting energy counters. See
Section 4.11
for information on configuring this feature on
the DTU3005B. The format of the command registers for
each device are described in
Appendix E
.
The DTU3005B can automatically update diagnostic infor-
mation in the PLC. It allows the PLC to determine when a
device is not communicating. See
Section 4.10
for informa-
tion on enabling and configuring this feature. The format and
content of the diagnostic registers are described in detail in
Appendix F
.
4.2
Configuring the Project File
Once you have created or opened the project file, select
Edit
from the main menu to display the following menu
items:
•
Port 1 (PLC)
—allows you to select the model and con-
figure the communications settings for the PLC con-
nected to port 1.
•
Port 2 (Devices)
—allows you to configure communi-
cations settings for SEAbus devices or Siemens Pro-
tective relays connected to port 2.
•
Port 3 (Passthrough)
—allows you to select whether
port 3 is used as a passthrough to the devices or the
PLC.
•
Diagnostics
—allows you to indicate if you want the
DTU3005 to write communications diagnostic informa-
tion to the PLC.
