homepage/legacy/posts/2014-01-18.01/article.html

define(`TITLE', `Another (better) MBus-Master, Part 3')
define(`DATE', `2014-01-18')
define(`CONTENT', `
Hardware has been extended by means to measure the current on the MBus and by a over current sensing, which will be extended to over current protection soon.


<a href="http://a385e-5.de/wp-content/uploads/2014/01/Foto-e1390078985461.jpg"><img src="http://a385e-5.de/wp-content/uploads/2014/01/Foto-e1390078985461-300x225.jpg" alt="Foto" width="300" height="225" class="alignnone size-medium wp-image-356" /></a>

<a href="http://a385e-5.de/wp-content/uploads/2014/01/MBusMaster2-1.png"><img src="http://a385e-5.de/wp-content/uploads/2014/01/MBusMaster2-1-300x220.png" alt="MBusMaster2-1" width="300" height="220" class="alignnone size-medium wp-image-355" /></a>



<blockquote><strong>Well, it seems, that this way of over current signaling to the MCU does not work properly. In the first design, the input of the comparator was directly the lower end of the shunt resistor, which worked. So, the differentiator is required of current measurement, but is not usable for over current signaling. Needs some more work.</strong></blockquote>



The both blue LEDs show activity on RX and TX, the red LED signals over current.

The whole development setup:

<a href="http://a385e-5.de/wp-content/uploads/2014/01/20140118-200610.jpg"><img src="http://a385e-5.de/wp-content/uploads/2014/01/20140118-200610-300x225.jpg" alt="20140118-200610.jpg" width="300" height="225" class="alignnone size-medium wp-image-351" /></a>

Power supply:

<a href="http://a385e-5.de/wp-content/uploads/2014/01/20140118-200600.jpg"><img src="http://a385e-5.de/wp-content/uploads/2014/01/20140118-200600-300x225.jpg" alt="20140118-200600.jpg" width="300" height="225" class="alignnone size-medium wp-image-350" /></a>

Load simulation:

<a href="http://a385e-5.de/wp-content/uploads/2014/01/20140118-200526.jpg"><img src="http://a385e-5.de/wp-content/uploads/2014/01/20140118-200526-300x225.jpg" alt="20140118-200526.jpg" width="300" height="225" class="alignnone size-medium wp-image-348" /></a>

Wave form of a simple communication:

<a href="http://a385e-5.de/wp-content/uploads/2014/01/20140118-200623.jpg"><img src="http://a385e-5.de/wp-content/uploads/2014/01/20140118-200623-300x225.jpg" alt="20140118-200623.jpg" width="300" height="225" class="alignnone size-medium wp-image-352" /></a>

(Yellow is the voltage on the bus, blue is the control signal of the sample-hold-device.)

The test client:

<a href="http://a385e-5.de/wp-content/uploads/2014/01/20140118-200540.jpg"><img src="http://a385e-5.de/wp-content/uploads/2014/01/20140118-200540-300x225.jpg" alt="20140118-200540.jpg" width="300" height="225" class="alignnone size-medium wp-image-349" /></a>

And finally, some communication with the master:

<a href="http://a385e-5.de/wp-content/uploads/2014/01/Bildschirmfoto-2014-01-18-um-22.13.50.png"><img src="http://a385e-5.de/wp-content/uploads/2014/01/Bildschirmfoto-2014-01-18-um-22.13.50-300x241.png" alt="Bildschirmfoto 2014-01-18 um 22.13.50" width="300" height="241" class="alignnone size-medium wp-image-364" /></a>
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