Siemens DTU3005-B - Manual (Page 7)

1
Introduction
Siemens Energy & Automation, Inc. 3
1.4.2 Modbus Master to SEAbus
The DTU3005 unit can be configured as a Modbus
(RTU) slave. In this configuration, a Modbus master
device (usually a SCADA system) is connected to port
1. The Modbus master uses the DTU3005 to monitor
and/or control Siemens ACCESS devices. A typical
Modbus application is shown below in Figure 1.5. The
passthrough port (port 3) can be used to connect to a
supervisory computer running WinPM software. It can
also be used to connect to a second, independent
Modbus Master device. This is shown in Figure 1.6.
Up to 32 DTU3005B units can be daisy chained using a
cable connected to port 1 of the three units. Each
DTU3005B device should have a different Modbus
device number. A daisy chained configuration is
shown in Figure 1.7.
Figure 1.5 Modbus Master to SEAbus
Figure 1.6 Two Independent Modbus Master Devices
to SEAbus
1 2 3
DTU3005B
Up to 32
ACCESS Devices
Acting as a Modbus
(RTU) slave. Data
is requested by
supervisory software.
Supervisory Software
on Modbus Master
RS-485
1 2 3
DTU3005B
Up to 32
ACCESS Devices
Acting as a Modbus
(RTU) slave. Data
is requested by
supervisory software.
Acting as a Modbus
(RTU) slave. Data
is requested by
supervisory software.
Supervisory Software
on Modbus Master
Independent Modbus Networks
Supervisory Software
on Modbus Master
RS-485