Category: Embedded Development

EDA Bug

I used a little trick on the 3-port Galvanic RSX as I connect to ground through the ground layer on layer 0. If you look at the area marked in green this is part of the ground, but the EDA don’t warn me that this is an iceland isolated from actual ground. I added a…

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Lab PSU 0-30V /10A – Part 7

Finally got the shunt resistors (red) and had to increase the width of the board due to their size. I have ordered the PCB’s so we should have them in ca 6 weeks time.

Lab PSU 0-30V / 10A – Part 6

This is the schematics for the regulator side of the Lab PSU. I am using the classic LM723 in this design which allow for current and voltage adjustments through potentiometers. T1 & T2 deliver a max of 15A each, but current will be limited by the shunt resistors R14 & R7 as well as R9…

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Distributed PLC Control Centre

Reviewing the design for a home automation system I realise that a PLC rack is not optional as a control system centre. The reason is that we will mainly be interested in central node processing and communication – we will not be interested in more classic PLC controls. Also we need these centrals to be…

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Lab PSU 0-30V / 10A – Part 5

As we log output voltage, current as well as few other things it would be nice to be able to display a real-time oscilloscope alike picture of these. This functionality is only available on PSU’s far more expensive, but is easy to achieve thanks to the Nextion displays. The illustration below is a draft of…

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Lab PSU 0-30V / 10A – Part 4

This metal box is not exactly the prettiest Project Box I have seen, but it cost 17.- USD including P&P and measure 250x190x110mm. I ordered one for testing because the more fancy alternatives cost closer to 100.- USD. What we now miss is the mains adapter with fuse, which is a 3.- USD component. We…

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Lab PSU 0-30V / 10A – Part 2

In part 1 I created an analogue linear regulator that can be used stand-alone as is. But, the drawback with a linear regulator is that it regulate by splitting voltage out between the load and the transistors. This means that if you short-cut the load you have 36V * 10A = 360W heating up the…

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