docu: added block diagram and FAQ to EvseMode.md

doc/EvseMode.md

@@ -13,12 +13,14 @@ To convince the car, that a CCS charger is connected, several preconditions need
 * On the ethernet port of the HomePlug modem we connect a computer which handles the high level communication. This may be a Windows10 laptop or a Raspberry or similar.
 * We need a power supply for the HomePlug modem and the Arduino-charging-logic, e.g. an USB power bank.
 
+![image](EvseMode_BlockDiagram.jpg)
+
 ## Software
 
 ### Configuring the HomePlug modem as Charging Station
 
 The homeplug modem needs a special configuration, to support the features which are needed for a charging station. We need to write a special configuration file to it. This is necessary only once, the modem will store the settings non-volatile.
-Details in readme.md chapter "Configuration of the PLC adaptor"
+Details in readme.md chapter "Configuration of the PLC adaptor".
 
 ### Installing pyPlc and openV2Gx on the computer
 See [Raspberry installation manual](installation_on_raspberry.md) or 
@@ -31,3 +33,43 @@ On the laptop, just run `python pyPlc.py E`.
 ![image](foto_EvseMode_IoniqOutside.png)
 ![image](foto_EvseMode_IoniqTrunk.png)
 
+## FAQ
+
+### Q1: What is the purpose of the PP pin, and do I need to connect it?
+
+The car uses the ProximityPilot (or PlugPresent) to detect, that a plug has been inserted. We need to connect a 1.5kohms resistor between
+the PP and the ProtectiveEarth (PE), otherwise the car most likely does not initiate any communication. The resistor can be directly placed
+into the plug.
+
+### Q2: Where can I address questions or distribute my testing results?
+
+Discussion is ongoing in the OpenInverter forum https://openinverter.org/forum/viewtopic.php?t=3551 "Drawing power out of CCS port (V2x, inverse charging, bidirectional CCS)"
+
+### Q3: How can I configure pyPLC in EVSE mode?
+
+There are two ways:
+1. In the pyPlc.ini, set `mode = EvseMode`. Then just run pyPlc without any command line parameter: `python pyPlc.py` (on Windows) or `sudo python pyPlc.py` (on Raspberry).
+2. No matter which mode has been configured in the ini file, you can overrule the setting on command line, by providing the letter E (like Evse) as first
+command line parameter: `python pyPlc.py E`.
+
+### Q4: Is it possible to close the cars contactors using this simple setup?
+
+It depends. The car only will close the contactors, when it is convinced, that the precharge phase is done. This means, the car sees that
+the charger has setup the voltage to the same level as the battery voltage of the car. There are three ways, how the car could determine
+the voltage on the CCS: (1) By physical voltage measurement on the CCS inlet, or (2) by relying on the voltage which is provided by the
+charger (it is called EvsePresentVoltage), or (3) by evaluation both methods (1) and (2) together.
+
+Each vehicle type has a certain behavior, some examples are collected in the OpenInverter forum (link above).
+
+### Q5: Can I use a BeagleBone instead of the Raspberry?
+
+Yes. Each linux computer which has an Ethernet port to connect the TPlink should work.
+
+### Q6: Can I use an other modem, e.g. YellowBeet or RedBeet?
+
+Yes. Just the following things need to be considered: The board must be integrated into the linux computer so that a (virtual) ethernet port is
+present. This interface name must be configured in the pyPlc.ini, so that pyPLC uses the correct interface. And the correct configuration of the modem must be used: A modem which is configured as PEV (car) will not work as EVSE.
+
+### Q7: Besides the Python version (pyPLC), is there an embedded solution available?
+
+Not at the moment. The embedded CCS solutions on ESP32 or STM32 are implementing the PEV (car) side only (https://github.com/uhi22/ccs32, https://github.com/uhi22/ccs32berta, https://github.com/uhi22/ccs32clara)