From ffc6c0eb0a0bc45c982d2929f00c1129456c0b7b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?H=C3=A5kon=20L=C3=B8vdal?= Date: Tue, 27 Feb 2018 00:17:02 +0100 Subject: [PATCH] Update documentation --- Electrical/Board_003/README.md | 46 +++++++++++++++++++++------------- 1 file changed, 29 insertions(+), 17 deletions(-) diff --git a/Electrical/Board_003/README.md b/Electrical/Board_003/README.md index ec6788d1..e78fff28 100644 --- a/Electrical/Board_003/README.md +++ b/Electrical/Board_003/README.md @@ -1,46 +1,58 @@ # Overview -This board can be used to simulate a M-Bus master unit instead of +This board can be used to simulate a M-Bus master device instead of connecting to the real AMS unit, i.e. usable for test and development. It takes a 5 V TTL level input (serial) signal and converts it -to a M-bus level signal. It only supports sending. Based on -[MBus_USB.pdf](https://github.com/rscada/libmbus/blob/master/hardware/MBus_USB.pdf)1. -It depends on an external power source capable of delivering 25-40 Volt. -Most DC-DC boost/step-up converter modules2 should be fine for this. +to a M-bus level signal. It supports both sending and receiving. +Inspired by [MBus_USB.pdf](https://github.com/rscada/libmbus/blob/master/hardware/MBus_USB.pdf)1, +although significantly improved by using zener diodes so that it is +flexible and can work with any external power source between +21 and 42 Volt. Most DC-DC boost/step-up converter +modules2 should be fine for this. ![](MBus_Simulator.png?raw=true) ## BOM -* D1 13V zener -* Q1-Q3 NPN transistor -* Q4 PNP transistor -* R1 1k -* R2 6.8k -* R3 1 (optional, can be shorted instead) -* R4 150 -* R5 22k -* R6 220k +* 1 x zener diode [13V](https://www.elfadistrelec.no/en/zener-diode-017aa-13-on-semiconductor-1n5350bg/p/17006687) (note below) +* 1 x zener diode [4.7V](https://www.elfadistrelec.no/en/zener-diode-do-35-500-mw-vishay-bzx55c4v7/p/30030851) +* 1 x [BD136 transistor](https://www.elfadistrelec.no/en/power-transistor-to-126-pnp-45-no-brand-bd136-16/p/17130046) (most pnp bjt will probably work (with 40+ operating voltage)) +* 4 x [BC337 transistor](https://www.elfadistrelec.no/en/transistor-to-92-npn-45-800-ma-diotec-bc337-25bk/p/30012857) (probably any npn bjt will do (with 40+ operating voltage) +* 1 x resistor 82 ohm +* 1 x resistor 1k +* 1 x resistor 8.2k (you can use 10k if power supply is well above 21V) +* 5 x resistor 10k +* 1 x resistor 220k +* 4 x pin header 1x2 -Note for the zener. This board depends on the zener to operate below 1mA, -e.g. like 1N5350 whereas a BZX55 will probably not operate properly. + +Note for the 13V zener. This board design depends on the zener to +operate below 1mA, e.g. like 1N5350 (figure 8) whereas a BZX55 +(figure 9) will maybe not operate properly. ![](zener_ok.png?raw=true) ![](zener_not_ok.png?raw=true) -This could be accomplished by reducing the 22k resistor so that it +This limitation could be lifted by reducing the 8.2k resistor so that it draws enough current. ## Schematic ![](MBus_Simulator.schematic.png?raw=true) +[SVG version](MBus_Simulator.schematic.svg?raw=true) ## PCB ![](MBus_Simulator.B.Cu.png?raw=true) +[SVG version](MBus_Simulator.B.Cu.svg?raw=true) ![](MBus_Simulator.F.Cu.png?raw=true) +[SVG version](MBus_Simulator.F.Cu.svg?raw=true) +## Version history + +Rev A - Only transmit. Wrong design, does not work. +Rev B - Both transmit and receive. Should work (not tested yet). -------------