Modbus to DNP3 Protocol Converter Group 24: Joshua Daly, CpE Daniel Doherty, CpE Mac Lightbourn, EE Joseph Wilkinson, EE

 Controllers like this one alternate which pumps in the lift station are active to maintain the desired flow rate and water level.  Other functions include ventilation control and alarms for high water or odor levels.  Many controllers are networked together and there is no industry-standard network protocol.

Modbus vs. DNP3 Project motivation: MPE needs to allow for communication between network nodes that are using these different protocols. CreatedMarket Difficulty of Implementation Equipment Costs Open Standard? Records time- stamped event sequences? Efficiency (bytes transferred for a given bandwidth) Modbus 1979 Widely used in all SCADA industries Low$100+NoWith DifficultyAverage DNP Sometimes used in water/ wastewater applications High $500- $3000 Yes Very High

Four-Semester Plan  Device Build  User Interface  Initialization Phase II  Network Communications  Security Phase I

Key Specs  Operates between -10 and 80 degrees Celsius  Protects against surges of 120 V  MCU clock has a backup battery that can power the MCU for 12 hours if power is lost  Sends alarm to master device when power is lost  Takes Ethernet input and gives Ethernet output  Allows user to view and change networking parameters  Logs 20,000 events, even when power is lost, with 98% fidelity  Records date and time of each event to millisecond accuracy  Notifies master device of all events with 95% fidelity

Four-Layer PCB Design

Choosing an MCU Microchip PIC32 TI Stellaris ARM Cortex M3 Freescale MC9S12NE64 Freescale MC9S12XDP512 Price/unit (bulk purchases)$1.58+$1.00+$6.93+$ Pins28, 36, or 4464, 100, 144, or or 11280, 112, or 144 Processor Speed80 MHz 16 MHz80 MHz Memory128 KB SRAM 256 KB SRAM, 32 KB Flash 64 KB Flash, 8 K RAM 512 KB Flash, 64 KB SRAM Special Considerations Cheap/free dev tools; extensive application notes Ethernet-ready Ethernet-ready with application notes; already widely used by the sponsor XGate coprocessor module; Non- multiplexed external bus interface; in same family as MCUs used by our sponsor

Ethernet Integration  Ethernet jacks include integrated magnetic isolation modules  Input and output both feature a dedicated Ethernet controller  Modbus input and DNP3 output interface with the MCU via SPI ports for high speed communications

ENC28J60 J NL

Noise Due to SPI Lines

 To reduce the noise, we took three measures 1. We placed pull-up resistors close to the microcontroller 2. We used large-value resistors for the pull-ups and large-value bypass capacitors 3. We isolated the MOSI and MISO lines with copper ground

Push Buttons and LEDs

Coding Environments  Visual Studio Used while PCB board was in development Familiar environment  Code Warrior Freescale MCU Optimization of.s19 file

Firmware Overview  Creation of data Structs to maintain parameters  Menu system Allows user to adjust stored parameters Strict requirements from the sponsor  Initialize all components on the PCB  Handle all button functionality

Firmware Challenges  Project requirements changed midway through  Integration of all parts on PCB  Delayed action based on buttons  Code must be well documented and easily modified

Data Storage  Stored in contiguous blocks  Storage requirements Factory defined User defined

Buttons  Required Guidelines  Button Functionality  Menu Navigation  Time Delayed press

Screen  Display Screen 3 7-segement displays  Mimic the current display used by MPE  Allows user to visually navigate and set parameters

Power Subsystem

Power Supply Requirements Takes in 24 V DC  This supply is shared with other components in the lift station control panel  This is a low voltage in comparison to other devices being used in industrial applications  The low voltage bypasses some of the testing requirements for meeting UL standards

Power Supply Requirements Surge Protection  Must handle currents up to 80 A  Must correct irregular voltages  Multiple devices are connected in a shunt configuration for combined benefits

Power Supply Requirements Type of DeviceLifetime-number of surges Response Time Transient Voltage Suppression Diode -1 ps Metal Oxide Varistor1000 surges1 ns Zener Diodeinfinite1 us Gas discharge tube20 surges5 us

Input Surge Protection

Power Supply Requirements Must be fed through a DIN rail mount  All devices in the lift station control panel attach to one rail  Mount also serves as chassis ground for added surge protection

DC/DC Converter  Voltage is stepped down to 3.3 V and then fed to the power plane  To conserve power, a passive switching regulator was chosen  Our configuration is a common circuit with extensive application notes

Financials ComponentPriceQuantityTotal Clock$2.344$9.36 Clock-Back Battery$4.281 Microcontroller$ Switching Regulator$3.751 Schottky Diode$0.551 TVS Diode$0.731 Inductor$3.561 LCD Driver$ Digit 7-Segment Display $2.911 Ethernet Controller$5.832$11.66 Ethernet Connector$4.732$9.46 Super-Red LED$1.082$2.16 Cyclone Pro Programmer $ Metal Oxide Varistor$0.561 Din Rail Connector$1.541 CaseDonated1 PCB$ Pin Connector$0.153$0.45 Resistor$0.0217$0.34 Capacitor$0.1220$2.40 Total $457.11