Meter data reading

[kundantirex]

Hi,
How can i send my meter data over cms after start transaction.
consider examples/ocpp16/quick_start_chargepoint example.
i want to send meter value after start charging, i it should send periodically as per mentions time interval in config .ini file.

[c-jimenez]

Hi,
To enable periodic sample meter values you need to configure the following 2 parameters in you your config.ini file:

• MeterValuesSampledData => List of meter values to send
• MeterValueSampleInterval => Interval in seconds of the meter values

Then the stack will automatically call the IChargePointEventsHandler::getMeterValue() method for each of the meter values configured in the MeterValuesSampledData config key at the interval configured in the MeterValueSampleInterval config key during the transactions.

[kundantirex]

Hi @c-jimenez,
After following these steps, do we need to manually call the getMeterValue() method after the transaction starts, or is it invoked automatically?
my code:
`} else if (j.contains("StartTransaction") && j["StartTransaction"].contains("idTag")) {
std::string tag = j["StartTransaction"]["idTag"];
AuthorizationStatus status = handleStartTransaction(*charge_point_ptr, connector_id_ref, tag);
response["StartTransactionResponse"] = {
{"idTag", tag},
{"status", AuthorizationStatusHelper.toString(status)}
};

            if (status == AuthorizationStatus::Accepted) {
                is_charging = true;
                charge_point_ptr->statusNotification(connector_id_ref, ChargePointStatus::Charging);
                std::this_thread::sleep_for(std::chrono::seconds(1));
                // handleSendMeterValues(*charge_point_ptr, connector_id_ref);
            }`

[c-jimenez]

Hi,
You dont have to call it, the stack will call it at the requested period.

[kundantirex]

Yes, but in my case, it's not working. That's why I thought I should call this function.

[c-jimenez]

Did you start the transaction using the startTransaction method of the IChargePoint interface ?

[kundantirex]

Yes, see
void handleStopTransaction(IChargePoint& charge_point, unsigned int connector_id,
const std::string& id_tag)
{
charge_point.stopTransaction(connector_id, id_tag, Reason::Local);
std::cout << "[TransactionHandler] Transaction stopped for connector " << connector_id << std::endl;
}

[c-jimenez]

Could you please zip your source code and share it to me so that I can investigate your issue?

[kundantirex]

Yes sure,
please check path /TestMessages,
in main.cpp i have creating API's using websocket. and after start transaction , meter value should send over cms. for now i have to check with static meter value.

testOCPP.zip

[c-jimenez]

I think that the main issue is here:

while (charge_point->getRegistrationStatus() != RegistrationStatus::Accepted) {
        std::this_thread::sleep_for(std::chrono::milliseconds(100));
    }

This waits forever until the charge point has been accepted by the csms.
But your websocket server simulating the csms is created after this loop.

[kundantirex]

another APIs is working correctly, only getting issue in this meter value.

[c-jimenez]

Ok I think I know what is missing: you didn't implement the following user callback properly (examples/common/DefaultChargePointEventsHandler.cpp):

/** @copydoc bool getMeterValue(unsigned int, const std::pair<ocpp::types::Measurand, ocpp::types::Optional<ocpp::types::Phase>>&, ocpp::types::MeterValue&) */
bool DefaultChargePointEventsHandler::getMeterValue(
    unsigned int                                                                        connector_id,
    const std::pair<ocpp::types::Measurand, ocpp::types::Optional<ocpp::types::Phase>>& measurand,
    ocpp::types::MeterValue&                                                            meter_value)

This method is automatically called by the stack for each configured meter value.
The stack will send the MeterValues message if both of the following conditions are met:

• The method returns true
• The meter_value.sampledValue array is not empty

You can take a look at the implementation done in the simu repo (https://github.com/c-jimenez/open-ocpp-simu) for an example on how to implement this callback.

[kundantirex]

Hey, there is an issue — even when the transaction hasn't started or has already stopped, the meter value is still being continuously sent to the CMS.