Orbit Power Monitoring

(By: Pavan A. Desai)

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Goal: The overall goal of this project is to measure and monitor the power consumption across each node in the ORBIT test bed by effectively mapping each node to the proper breaker switch on the breaker board.

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Requirements:

• Mega Arduino Board (Need both Arduino hardware & software for processing purposes)
• Arduino Ethernet Shield (Need to connect the Arduino Board to different networks)
• ORBIT Power Sensing Platform (Need to measure power)
• PuTTY Pageant Software (Used to connect to ORBIT's "Grid Network" from ones PC to observe the collection of data)
• PuTTY SSKEY (Used to create a secure shell key for secure data communication, PuTTY Pageant will require it for all ORBIT network connections)
• Ruby (Will be needed to parse XML output)
  

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Overall Operation:

Figure 1: Full View

1) Total of 4 nodes are connected to one outlet.
2) 2-3 Outlets are connected to a single breaker switch.
3) On the breaker board there is a toroid connected behind each breaker switch.
4) A Brultech Micro-40 Donut Style toroid is used to scale down the current at a ratio of 40A to 26.23mA.
5) The ends of the toroid sensors are connected to the ORBIT Power Sensing Platform.
6) The ORBIT Power Sensing Platform is connected to the Arduino board and shield.

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Power Sensing Platform:

Figure 2: Sensor Board

Once the current is stepped down by the toroid, a 42Ω resister is used to convert the AC current into AC voltage at the entrance of the Power Sensing Platform. Then the AC voltage is converted to DC voltage by going through AD737JNZ chip with a average off-set of 3.364mV between the input and output of the chip. The voltage regulator is used to lower the voltage that powers the AD737JNZ chip to values of ± 2.5V from ± 3.3V. The inverting amplifier with a gain of 4.7 is used to convert the negative voltage value outputted from the AD737JNZ chip to a positive value because the Arduino does not accept negative inputs. Once the signal enters the Arduino analog pins, the Arduino will read the signal at the analog pin and output a resolution reading between 0 to 1023. The Arduino has a 10-bit analog to digital converter so it will map input voltages between 0 and 5 volts into integer values between 0 and 1023. Then the software part of this project will fix the off-set of the AD737JNZ chip and the scaling factor of the toroid along with adjusting the Arduino to covert the resolution readings to power readings.

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Procedure:

1: Connect the Arduino Board and Arduino Ethernet Shield to the ORBIT Power Sensing Platform. The Arduino board will be connected to the bottom of the ORBIT Power Sensing Platform and the Arduino Ethernet Shield will be place on the top of the ORBIT Power Sensing Platform as shown below:

Figure : Connection

2: Upload the following code to the Arduino board from the attachments: PowerSensingCode.ino

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Current Progress: