This is a very basic C++ library for Arduino, Implementing SEMP "Simple Energy Management Protocol" from SMA Right now it works for Esp8266 only, due to the internal usage of Esp8266WebServer. Something that i will probably never address...

Installation

To install this library, just place this entire folder as a subfolder in your Arduino/lib/targets/libraries folder.

When installed, this library should look like:

Arduino/lib/targets/libraries/uSEMP (this library's folder) Arduino/lib/targets/libraries/uSEMP/uSEMP.cpp (the library implementation file) Arduino/lib/targets/libraries/uSEMP/uSEMP.h (the library description file) Arduino/lib/targets/libraries/uSEMP/keywords.txt (the syntax coloring file) Arduino/lib/targets/libraries/uSEMP/examples (the examples in the "open" menu) Arduino/lib/targets/libraries/uSEMP/readme.txt (this file)

Dependencies

• ESP8266WiFi
• ESP8266mDNS
• ESP8266SSDP
• ESP8266WebServer ( will change to AsyncWebserver )
• uHelper: https://github.com/hessenud/uHelper.git - some helper components

NB: after fooling around with this library i've gained a better idea what i really want and need from a SEMP Library. That means I will completely overhaul this library and make a new version. This version will be interface incompatible but with clearer separation responsibilities and will be more re-usable outside Arduino...

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Usage

After this library is installed, you just have to start the Arduino application. You may see a few warning messages as it's built.

To use this library in a sketch, go to the Sketch | Import Library menu and select uSEMP. This will add a corresponding line to the top of your sketch:

#include <uSEMP.h>

To stop using this library, delete that line from your sketch.

The Library lets you create a SEMP Device with it's own EM Gateway

uSEMP( const char* i_udn_uuid,const char* i_deviceID, const char* i_deviceName, const char* i_deviceType
		, const char* i_seviceSerial, const char* i_vendor, unsigned i_maxConsumption
		, bool i_interruptible=true, bool i_acceptOptional=true
        , bool i_absoluteTimeStamps=false, ESP8266WebServer* i_server, unsigned i_port );

The constructor needs a pointer to a webserver and its port used for serving SEMP requests

uSEMP* g_semp = new uSEMP(...);

void setCallbacks( unsigned long (*i_getTime)()
        , void (*i_sigEmS)( EM_state_t )
        , void (*i_sigEoP)( ) ) 

The SEMP object requires a few callbacks:

• a "time()" function to get access to the device's timebase. This is needed for generating planning requests.
• a "signalEMState" callback for feedback of EM Control to the device application "setPwr"
• a "end-Of-Plan" callback so signal the end of an active plan

To make itself known to the Energy Manager (EM) the device uses SSDP. The Arduino ESP8266SSDP Library is somewhat limited but still usable, as long as you overwrite the Schema. The uSEMP class provides a makeSsdpScheme() method. I haven't found a satisfying way to put that inside the SEMP Library. This is something i will target someday...

...

SSDP.setSchemaURL( ssdpcfg.descriptionURL); //< this 
...
const char* ssdpScheme = g_semp->makeSsdpScheme( &ssdpcfg);
http_server.on(String("/") + ssdpcfg.descriptionURL, HTTP_GET, [ssdpScheme]() {
  http_server.send(200, "text/xml", ssdpScheme ); 
});

Now the device is effectivly started after the SEMP Service and SSDP is started

	void startService( );   
	g_semp->startService(); 
	SSDP.begin();

When operational you may request energy, and update the actual energy-request (plan)

/**
 *  request energy
 *  @param  i_now		timestamp in seconds ( e.g. unix time seconds since 1970... )
 *  @param  i_req 		requested energy in [Wh]
 *  @param  i_optional		optional energy in [Wh]
 *  @param  i_est		earliest start time in seconds (absolute timestamp like i_now)
 *  @param  i_let		latest end time in seconds (absolute timestamp like i_now)
 *
 *  @return handle to created plan, -1 if creation failed
 */
int requestEnergy(unsigned i_now, unsigned i_req, unsigned i_optional, unsigned i_est, unsigned i_let );


/**
 *  request time
 *  @param  i_now       timestamp in seconds ( e.g. unix time seconds since 1970... )
 *  @param  i_minOnTime       requested minumum on time in[s]
 *  @param  i_maxOnTime   requested maximum/optional on time in[s]
 *  @param  i_est       earliest start time in seconds (absolute timestamp like i_now)
 *  @param  i_let       latest end time in seconds (absolute timestamp like i_now)
 *
 *  @return handle to created plan, -1 if creation failed
 */
int requestTime(unsigned long i_now, unsigned i_minOnTime, unsigned i_maxOnTime, unsigned i_est, unsigned i_let );



/**
 *  update runtime/ energy (differentially )
 *  @param  i_now		timestamp in seconds ( e.g. unix time seconds since 1970... )
 *  @param  i_req 		change of required  energy in [Wh]
 *  @param  i_optional		change of optional  energy in [Wh]
 */
void updateEnergy(unsigned i_now, int i_req, int i_optional);

An energy plan is updated using updateEnergy

 g_semp->updateEnergy( now, -1, 0);  // reduces required energy of the actual energy request by 1Wh
 
 g_semp->getPlan(2)->updateEnergy( now, -1, 0);  // reduces required energy of the plan 2 by 1Wh
 
 g_semp->deleteEnergyRequest( 2);  // delete energy request 2

ToDo:

• seperate energy/time requests from planing request to the EM
• better separation/organization of responsibilities => new API
• there is too much application in this library (update Energy..) limiting an application this way