Addressable Protocols

lilrags16 · December 31, 2014, 6:43pm

Retired STR-SG:

lilrags16:

Can someone explain how the SLC powers devices? I do understand the serial(?) system for data, just not how the heck it powers it…

I can only answer that for Mapnet, but the others are probably somewhat similar. If someone has looked at some other brands with a scope they can fill in that information.

The drawing below represents a Mapnet poll and answer of one device. The channel is powered by 36 volts DC. A poll begins with a sync pulse which is only a few milliseconds… Then the Mapnet card polls the device address. That data is only around 10 volts. The device responds by switching a resistor on and off which is sensed in the Mapnet card. So 99.99% of the time the devices have between 26 to 36 volts power available. Capacitors in the devices smooth out the variations in voltage to power the internal circuit.

Is MapNet an older protocol? I would love to make a addressable demo board.