# #TwoMinuteTeardown: Corporate Systems Engineering SSHAAC00-S041911 # Corporate Systems Engineering SSHAAC00-S041911 Electric utilities can employ ["load shed" devices](http://corporatesystems.com/?page_id=64) throughout their grid to manage load. These devices are usually found on air conditioners, water heaters, pool pumps and other large electrical loads. Typically they'll offer you a small financial incentive to allow the utility to cycle your device off for short periods of time during peak demand events. The Corporate Systems Engineering SSHAAC00-S041911 is one such device. As you might expect from a single purpose device, the internals are pretty straightforward. There is a modem/radio side to communicate with the utility, and a power switching side to understand and control the load. This unit fell into my hands after it was taken off an air conditioner during a service call. {{
}} A bit counter intuitively, the entire assembly is attached to the lid of the enclosure and not the main body. This will start to make more sense when looking at a few other details below. {{
}} The purple and grey wires ran off to a CT clamp that was installed around one of the AC compressor lines. {{
}} Small patch style antenna (`WPANT10170-S2B`) for the radio attached to the side of the 'lid' with a sticky pad. {{
}} Taking a closer look at the main PCB and going in no particular order. {{
}} {{
}} The PCB has cutouts for a few different LEDs, not all are populated in this unit. {{
}} {{
}} There really isn't much to see on the bottom of the main PCB. **Big** traces for the mains side of things, lots of clearance around everything else and a lot of ground plane stapling/via-stitching on the low voltage side of things. {{
}} Both the transformer and the single relay are `Zettler` parts. The caps are `Nichicon`. No expense spared it seems! {{
}} {{
}} {{
}} The ARM seems to do house keeping... although it's probably overkill for what this device needs to do. The 'tall' pin headers are where the modem module mates. {{
}} Speaking of the modem module... {{
}} {{
}} {{
}} {{
}} ## ICs In - roughly - the order they appear in the photos above. ### Power ```text 324 MZJF150 ``` The [LM324](https://www.st.com/en/amplifiers-and-comparators/lm324.html) quad op-amp. For what, exactly, I'm not sure. ```text ATMEL M90E26-YU 2249 2249W66 ``` The [M90E26](https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-46002-SE-M90E26-Datasheet.pdf) is a _very_ accurate single phase energy metering IC. ```text Zettler AZ943-1CH ``` [AZ943-1CH](https://www.azettler.com/pdfs/az943.pdf) is the 'dry contract' wired in series with the thermostat to switch the AC compressor on/off. ```text L2207 LTV827 ``` [Lite-On LTV-827](https://datasheet.octopart.com/LTV-827-Lite-On-datasheet-7282434.pdf) optoisolator. This is almost certainly for isolating the `M90E26` from the rest of the low voltage side of things. ```text MIC 69153YME ``` [Microchip MIC69153](https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/MIC69153-Single-Supply-VIN-LOW-VIN-LOW-VOUT-1.5A-LDO-DS20006019A.pdf) is power conditioning for the housekeeping MCU. ```text 0AD8 L22676 ``` [Texas Instruments LM22676](https://www.ti.com/lit/gpn/LM22676-Q1) is power supply for the low voltage side of things. ```text 32F100 RDT6B GQ277 93 ``` [ST STM32F](https://www.st.com/en/microcontrollers-microprocessors/stm32f100-value-line.html) is the main housekeeping MCU. ```text 95M01RP K109K ``` [ST M95M01](https://www.st.com/en/memories/m95m01-r.html) is flash memory for the MCU. ```text PZGM TI 268 ``` [Texas Instruments TPS7A8300](https://www.ti.com/lit/ds/symlink/tps7a8300.pdf) is another power conditioning IC. ### Modem The modem module appears to be `Itron` [OWS-NIC511-06](https://fccid.io/OWS-NIC511-06). As far as I can tell, `Itron` acquired `Silver Spring Networks` who originally developed the module. The PCB has quite a few unpopulated footprints and design features; each customer/region(?) gets a slightly different configuration based on their needs. At least in _this_ configuration, it uses 915MHz ISM band and a mesh technology that Itron calls [`OpenWay`](http://corporatesystems.com/?page_id=47). I'll defer you to the excellent work of [@RECESSIM](https://www.youtube.com/@RECESSIM) for some details on smart meters and mesh networks. ```text Silver Spring Networks 130-0117-01 Rev 8.0 VQ239257 GW00E 07 E ``` Appears to be ["endpoint security module"](https://csrc.nist.gov/CSRC/media/projects/cryptographic-module-validation-program/documents/security-policies/140sp3445.pdf). ```text ESMT M14D128168A AZY2 -2.5 BI P2A2509 216 ``` [DDR 2 memory](https://www.esmt.com.tw/upload/pdf/ESMT/datasheets/M14D128168A(2Y)_operation%20temperature%20condition%20-40~95%C2%B0C.pdf) ```text RFFM SSN1 VZ7K ``` I can't find anything definitive on this one but it's clearly a front end module for the RF side of things. ```text Atmel 86RF215 ``` Atmel [AT86RF215](https://www.microchip.com/en-us/product/at86rf215) Sub-GHz / 2.4GHz Transceiver and I/Q Radio ```text SiGe 2435L 24OCM ``` [SkyWorks SE2435L](https://www.skyworksinc.com/products/front-end-modules/se2435l) is a power amplifier for the 902-928MHz ISM band.