IPEX IoT Power Energy Controller Expansion Board

Story

The recently released IPEC (IoT Power Energy Controller and Monitor SDK), includes an expansion header (JST 6 Pin SH) . This IPEX (IoT Power Energy Controller Expansion), Board has been designed to interface to this, or can be used as a stand-alone development board.

My plan is to expand the IPEX range to offer different interfaces, all connecting into the IPEC, or able to be used as base development boards.

All IPEX boards will be stackable above, or below, an IPEC SDK Board. Up to FOUR IPEX-1 boards can be stacked - each with a different ADC address.

Board Purpose

Accurately monitoring Mains Power Energy Current and Power, with real-time import and export values, can be provided from the original IPEM board (using either the ATM90E32 or ATM90E36). IPEX takes this a step further by maintaining the IPEM main ATM90E32 functionality but also allowing additional sensors to be added and integrated easily. Solar Power Diverter use.

The purpose of this IPEX expansion board(s), is to allow for sensor inputs and output to be added.

Top Level

• Four ADC Inputs (Three Primarily). These go into a 16bit ADS1115 I2C ADC.
• One Fully Isolated On-Board AC or DC Current Sensor (ACS758 Series)
• Four DAC Outputs (Two Primarily). These can go via FET Voltage Level Shifters or OpAmp Voltage Gain/Followers.
• Stackable Boards. More inputs or outputs.

DC Current Monitoring

The main reason for including the ACS758 series, was to allow the DC battery supply current to be monitored on an Inverter / Solar Charge Controller. Thus, using the IPEC and IPEX boards together, makes a simple solution which will both monitor one, two or three, or split phase mains supply, plus the DC Current flow.

Solar Power Diverter

The reason for the DAC interface, is to allow the board to output PWM/MPPT/Modulated, based on the tracking of CT Clamp and Power values using the ATM90E32 values. So, the PWM or Output Voltage can track the varying mains current and used for Solar Power Diverter such as Immersion control, or Battery charge current.

Basic Specification

IPEX-1, is a DAC/ADC four channel Interface, with ACS758 Current Monitor. It includes the following features:

• IPEC Interface Header and Pass-Through Header, for cascading boards.
• - Interface is fully configurable
• - I2C Interface
• - 3V3 Power
• Four ADC inputs, to an ADS1115 16bit ADC
• - Inputs are fully configurable
• - Voltage Monitoring
• - Temperature Sensing
• ACS758 Fully Isolated, AC or DC, Current Sensor (100A)
• Four DAC Outputs, (via the below FET / OpAmp Drivers).
• - PWM Output - Tracking CT/Power
• - Fixed Voltage Output - Tracking CT/Power
• - MPPT or Modulated Output - Tracking CT/Power
• DAC FET Outputs for Voltage level Shifter, with Invert and Non-Inverted Outputs
• - FET Interface is fully configurable
• DAC Op-Amp Buffer Amplifier, with Low Pass Filters, Voltage Follower.
• - Op=Amp Interface is fully configurable
• DC-DC 5V LDO
• - DC Power Input Header
• - Power LED

Status (BETA)

The IPEX-1 board is in Beta Test Phase, with the board currently in SMT production for testing for testing Early July. Full production boards will then be available later in July.

Status Update 16th July 2023

The IPEC board has been going through bring up and testing. All is looking good so far and apart from a couple of minor improvements which has come out of testing, it look very positive.

Interfacing to the IPEX board worked without any issues and this enabled basic bring up testing of the DAC and ADC to move forward. The IPEX board will then be updated to make minor improvements, so expanding a couple of worthwhile features. Still pinning down the final PWM interface but ideas are on the bench.

The biggest amount of time has been spent on the firmware. Taken the IPEM base code, added automatic detection between IPEM, IPEC and IPEC with IPEX. Then a whole chunk of IPEC and IPEX interfacing code was spread on top.

Overall, I am pleased with progress and this IPEC board is looking to be a very versatile board - especially for those whom would like to delve further into Solar Power Diverters.

Already as seen in the below photo, the IPEC/IPEX board is interfacing to a High Power Motor controller to provide automated Batter Charge control based on surplus energy. This is working really well.

Using the IPEX DC Current Sensor, it is also possible to monitor the charging, as well as Solar Diverting.

Will pursue testing and code development over the next week and this should enable a line to be drawn in the current design.

Status Update 22nd July 2023

The below shows the PWM and DAC working together for MPPT.

The current clamp is connected to a variable ramping load and this is then used to test the IPEC board which is automatically outputting the DAC and PWM, based on the Power.

Further details will follow.

Updates code can be found on our GitHub.

The full specification list is available here.

Further details maybe also be found on our GitHub

Further Information

Additional information, and other technical details on this project, maybe found in the related repository pages.

Repository Folders

• Code (Code examples for Arduino IDE and PlatformIO)
• Datasheets and Information (Component Datasheets, Schematics, Board Layouts, Photos, Technical Documentation)
• Certification (Related Repository Project or Part, Certification Information)

Repository Tabs

• Wiki (Related Repository Wiki pages and Technical User Information)
• Discussions (Related Repository User Discussion Forum)
• Issues (Related Repository Technical Issues and Fixes)

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Dave Williams, Eastbourne, UK.

Electronics Engineer | Software Developer | R&D Support | RF Engineering | Product Certification and Testing | STEM Ambassador

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