Figure 4.2.1: Modbus TCP data stream Re-printed with permission from MPE. DNP3 is a newer SCADA standard that has found a home mainly in the electric utilities. Only recently has it begun to move into waste water utilities. Benefits include the increased security provided by specialized security objects in the data stream as well as being Wi-Fi capable. DNP3 used the same modified 5-layer model. Along with the increased security measures, it has the capability to change the Modbus master-slave relationship to a master-master relationship. This allows messages to be sent and received by the device and the master control center. The functionality of DNP3 far exceeds that of Modbus, Modbus has 10 function codes that might be applicable to this device where DNP3 has closer to 20 function codes that are applicable. A Modbus to DNP3 gateway device has a detailed software design. The model that was chosen was the waterfall model figure 4.0.2. First off, it was a simple enough design process that wouldn’t slow down the development of the product by constant testing every step taken and yet it still provided a nice outline and flow overall. The design team could follow the waterfall life cycle step by step up to the maintenance which is where it would hand off the product to the sponsor, MP electronics. Figure 4.2.2: Waterfall lifecycle model Re-printed under a creative commons license The fact that this model had sequential progression through its steps allows one to easily work through the design process. While generally this method is considered more for hardware, the software team found that it would fit the project’s purposes quite well solely on the time factor. The team would not have the more than 4 months to code all the firmware for this project. The thought that anyone would have a working model and it would need an improvement in four months is just unrealistic. After that time frame, MP electronics would have the
Figure 4.2.1: Modbus TCP data stream Re-printed with permission from MPE. DNP3 is a newer SCADA standard that has found a home mainly in the electric utilities. Only recently has it begun to move into waste water utilities. Benefits include the increased security provided by specialized security objects in the data stream as well as being Wi-Fi capable. DNP3 used the same modified 5-layer model. Along with the increased security measures, it has the capability to change the Modbus master-slave relationship to a master-master relationship. This allows messages to be sent and received by the device and the master control center. The functionality of DNP3 far exceeds that of Modbus, Modbus has 10 function codes that might be applicable to this device where DNP3 has closer to 20 function codes that are applicable. A Modbus to DNP3 gateway device has a detailed software design. The model that was chosen was the waterfall model figure 4.0.2. First off, it was a simple enough design process that wouldn’t slow down the development of the product by constant testing every step taken and yet it still provided a nice outline and flow overall. The design team could follow the waterfall life cycle step by step up to the maintenance which is where it would hand off the product to the sponsor, MP electronics. Figure 4.2.2: Waterfall lifecycle model Re-printed under a creative commons license The fact that this model had sequential progression through its steps allows one to easily work through the design process. While generally this method is considered more for hardware, the software team found that it would fit the project’s purposes quite well solely on the time factor. The team would not have the more than 4 months to code all the firmware for this project. The thought that anyone would have a working model and it would need an improvement in four months is just unrealistic. After that time frame, MP electronics would have the
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