How should RemoteStartTransaction be implemented?

[lucianosilvi]

Hello, I'm trying to trigger remote start transactions, for that, using the example on the docs, I have: `class MyChargePoint(cp):

    @on(Action.BootNotification)
    def on_boot_notitication(self, charge_point_vendor, charge_point_model, **kwargs):
        return call_result.BootNotificationPayload(
            current_time=datetime.utcnow().isoformat(),
            interval=10,
            status=RegistrationStatus.accepted
        )

    # @on(Action.RemoteStartTransaction)
    def remote_start(self, id_tag, **kwargs):
        """
            Send remote start transaction to CP
        """
        return call.RemoteStartTransactionPayload(
            id_tag=id_tag
        )

I implemented other method that calls remote_start under certain conditions, however when this method is called (remote_start) nothing is sent to the CP websocket. Is this normal? How can I check if the remote start action was received by the Charger? I'm running both ends to simulate the behaviour (Central System and CP) to check everything works fine.

Thanks

[OrangeTux]

I'm sorrry for missing this completely. But you seem to return the wrong payload. Instead of using call.RemoteStartTransactionPayload you should use call_result.RemoteStartTransactionPayload.

[MrMika96]

Can you make an example of how to create remote_start_transaction on both central system and charge point? Because i have this on central system part:

    async def remote_start_transaction(self):
        request = call.RemoteStartTransactionPayload(
            id_tag='1'
        )

        response = await self.call(request)
        if response.status == RemoteStartStopStatus.accepted:
            print("Transaction Started!!!")

and this on charge point part:

@on(Action.RemoteStartTransaction)
def remote_start_transaction(self, id_tag):
    return call_result.RemoteStartTransactionPayload(status=RemoteStartStopStatus.accepted)

And charge point is receiving id_tag, but sending call_result somewhere else, i think

[OrangeTux]

Closed due inactivity. Feel free to reopen if needed.

[TehEckoz]

Hello, I have a question, when making a remote transaction, it asks me to pass 3 parameters, two of them optional.

The id_tag, connector_id and the charging_profile.

Indeed I see that by passing the id_tag ​​and the connector_id, it connects to the charger.

But if I have different charger points, how do I identify which charger is correct to select the connector_id?

[OrangeTux]

When you use this library to implement a CSMS, an instance of ChargePoint is created for OCPP that is opened at your CSMS.

If you want to set a RemoteStartTransaction to a specific charger, you need to find the corresponding instance ChargePoint. Use that instance to send a message to the charger.

See also this thread: https://github.com/mobilityhouse/ocpp/issues/263. That contains some code to send a Reset payload to a specific charger.

[TehEckoz]

Thanks for answering,

My question is the following, I understand that before calling remote start transaction we should identify the loading point where we will start the transaction.

How do I identify one charging point or another. Right now, having two charging points makes me turn on both.

[OrangeTux]

You need to find the right ChargePoint instance based on the id of the charger. For example, by using ChargePoint.id.

[TehEckoz]

Hello again,

This is what I am passing in my central_system, and I am running it by cmd with py central_system.py

But I don't really understand how to get the charging point

request = call.RemoteStartTransactionPayload(
                id_tag=id_tag,
                # connector_id=1,
                # charging_profile= 
                charging_profile={  
                                    "connector_id": 1,
                                    "csChargingProfiles": {
                                        "chargingProfileId": 1,
                                        "chargingProfileKind": "Absolute",
                                        "chargingProfilePurpose": "TxDefaultProfile",
                                        "chargingSchedule": {
                                            "chargingRateUnit": "W",
                                            "chargingSchedulePeriod": [
                                                {
                                                "limit": 2,
                                                "startPeriod": 0,
                                                }
                                                ],
                                                "duration":86400
                                        },        
                                        'stackLevel': 1

                                    },
                }

            )``

This is correct? If so, how do I have to call the charging point, or how should I obtain it so that I can execute the remote start transaction to a single specific charging point.

Thank you and sorry for the inconvenience.

[OrangeTux]

You must have some logic in your CSMS that creates a ChargePoint instance when a charger connects. Store that instance somewhere.

Next, in your code concerned with sending the request, retrieve the ChargePoint you stored earlier, build the request and execute await your_charger.call(...).

This comment might help you.

[TehEckoz]

I attach an image with what the cmd returns and with what I have put in code in start remote transaction and on_connect in central_system.py

[OrangeTux]

I'm lost. What is your question?

[TehEckoz]

It returns Rejected, I cannot identify a single load point before the remote start transaction

[TehEckoz]

In the CMD it returns the same thing twice, because it is collecting both charging points, I need to be able to visit only the one I choose or decide

[OrangeTux]

You connection handler contains

await asyncio.gather(cp.start(), cp.remote_start_transaction())

That instructs the handler to remotely start a transaction as a charger connects. If you don't want that, remove the cp.remote_start_transaction().

In that same connection handler, a ChargePoint instance is created. You should store that instance somewhere.

Next, in your code that triggers a remote start transaction you should retrieve relevant ChargePoint instance and call cp.remote_start_transaction() on it.

In this example that I linked earlier, the ChargePoint instances are stored in CentralSystem._chargers. The CentralSystem.reset_fun() iterates of the connected chargers and calls cp.reset() on the charger that matches a filter.

[TehEckoz]

Until now, when I pass only a single charging point (charging station). I execute remote start correctly.

But if I have more than one charging point (charging station), it makes me rejected from the second one.

This is what I have done, I don't know if it is correct. or it could be done another way.

async def remote_start_transaction(self):
        print('FUNC. REMOTE')
        results = []

        try:

            with pyodbc.connect('DRIVER={SQL Server};SERVER=X;DATABASE=X;UID=X) as connection:
                while True:
                    row = connection.execute("select top 1 id_tag, connector_id, charged_point_id from RemoteStart where valido = 1").fetchone()

                    if not row:
                        break  

                    id_tag, connector_id, charged_point_id = row

                    print('User: ', id_tag)
                    print('Connector: ', connector_id)
                    print('Charged Point:', charged_point_id)

                    request = call.RemoteStartTransactionPayload(
                        id_tag=id_tag,
                        connector_id=connector_id
                    )

                    print('RemoteStartTransactionPayload Request: ', request)

                    try:
                        response = await self.call(request)
                        print('Request Response:', response)

                        if response.status == RemoteStartStopStatus.rejected:
                            print('Rejected')

                        if response.status == RemoteStartStopStatus.accepted:
                            print("TRANSACTION START")
                            connection.execute("UPDATE RemoteStart SET valido = 0 where id_tag = ? and charged_point_id = ? and connector_id = ?", id_tag, charged_point_id, connector_id)
                            connection.commit()
                            print("¡COMPLETED!")
                            results.append(call_result.RemoteStartTransactionPayload(status=RemoteStartStopStatus.accepted))

                    except Exception as e:
                        print(f"Error in the call a self.call: {e}")

        except Exception as e:
            print(f"Error in the connex BBDD: {e}")

        if not results:
            print('NO REMOTES TRANSACCTION')

        return results

[TehEckoz]

In On_Connect I do this:

async def on_connect(websocket, path):
    charge_point_id = path.strip('/')
    cp = ChargePoint(charge_point_id, websocket)

    while True:
        print('CONSULT. REMOTE')
        cursor = pyodbc.connect('DRIVER={SQL Server};SERVER=X;DATABASE=X;UID=X')
        valido = cursor.execute("select count(valido) from remotestart where valido = 1").fetchone()[0]
        cursor.close()

        if valido > 0:
            cursor = pyodbc.connect('DRIVER={SQL Server};SERVER=X;DATABASE=X;UID=X')
            id_tag = cursor.execute("select top 1 id_tag from RemoteStart where valido = 1").fetchone()[0]    
            connector_id = cursor.execute("select top 1 connector_id from RemoteStart where valido = 1").fetchone()[0]
            chrg_point_id = cursor.execute("select top 1 charged_point_id from RemoteStart where valido = 1").fetchone()[0]
            cursor.close()

            if charge_point_id == chrg_point_id:
                await asyncio.gather(cp.start(), cp.remote_start_transaction())
            else:
                print('')
        else:
            print('0 TRANSACTIONS REMOTES')
            await asyncio.sleep(5) 
            continue  

        try:
            await asyncio.gather(cp.start())
        except websockets.exceptions.ConnectionClosed:
            connected.remove(websocket)
            print("Charge Point disconnected")

        await asyncio.sleep(5)