1 Introduction
1.4.2Modbus 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.
Supervisory Software
on Modbus Master
DTU3005B
1 2 3
Acting as a Modbus (RTU) slave. Data is requested by supervisory software.
Up to 32
ACCESS Devices
Figure 1.5 Modbus Master to SEAbus
Independent Modbus Networks
Supervisory Software | Supervisory Software | |||||||||
on Modbus Master | on Modbus Master | |||||||||
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DTU3005B
1 | 2 | 3 |
Acting as a Modbus |
| Acting as a Modbus |
(RTU) slave. Data |
| (RTU) slave. Data |
is requested by |
| is requested by |
supervisory software. |
| supervisory software. |
Up to 32
ACCESS Devices
Figure 1.6 Two Independent Modbus Master Devices to SEAbus
Siemens Energy & Automation, Inc. | 3 |