View single post by mattbrain
 Posted: Friday Feb 16th, 2018 04:17 pm
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mattbrain



Joined: Tuesday Jun 12th, 2007
Location: United Kingdom
Posts: 185
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The RPi CM3 has 4Gb of built in flash which would store the operating system, code and configuration. I am currently working on having the O/S and code mounted in read only mode and considering different options for storing configuration data (including both central server and local options). The USB ports are for capability expansion and future proofing.

From a PSU perspective, we are currently running some tests. It is anticipated that the existing PSU would be able to provide enough current for the base RPi UCM provided the host panel PSU (Comfort or Slave) is not already unduly loaded (e.g. isn't powering other slaves or UCMs). The CM3 will utilise around 700ma @ 5v which is around 350ma @ 12v allowing for some losses in the voltage regulator. The additional support hardware (UCM, Ethernet and USB hub) will also consume additional current but should be within a reasonable tolerance so long as current hungry USB devices aren't plugged in (hard disks, wifi adapters etc).

If we do chose to utilise the USB for power hungry devices, we may need to up the PSU, provide a separate PSU for the UCM or use a powered hub but this needs to be considered in the context of the whole Comfort system, ease of integration and other PSU tolerances within the existing platform - and Chiu and his team have far more knowledge than me on those requirements.

Incidentally, during testing I was running last week, I had a test Comfort main board, 1 UCMEth, 1 UCMRPi, 1 Keypad and 2 PIRs running on a standard backup battery for a couple of hours whilst i investigated some issues. During this period I didn't experience any power related issues so don't anticipate (at this point) that most standard installs without additional peripherals will require changes to the PSU.

Thanks,

Matt

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