BiDi OCPP 1.6J Charging Profiles with negative numbers for Bidirectional Chargers

[StefanRiedAV]

Hi,
CitrineOS is exactly what I was looking for.
Thanks for sharing and developing it. You are great!

We are currently running a POC with bidirektional charger.
(I know this is really cool finally in OCPP 2.1 with the DER definitions...)

Until this the vendors of bidi charges agreed to handle negative numbers in OCPP1.6J Charging Profiles.
I am wondering (before we invest a lot of testing time), if the citrineOS-core handles negative numbers end2end, of it I need to patch much in the core.

Anybody used it for bidi control already?

Thanks for your feedback.

Stefan

[yuvenus]

Hello @StefanRiedAV, yes, CitrineOS should be able to handle negative numbers for bidirectional charging. Please give it a try, thank you!

[StefanRiedAV]

this is great news. I will definitely try this out.

Unfortunately, some of the Bidi chargers prefer still OCPP 1.6J, and there is no handling of the ChargingProfile for OCPP 1.6J implemented in Citrine 1.8.x as far as I see.
So, I will try to get some OCPP2.0.1 chargers into the current project.

[StefanRiedAV]

folks, If anybody needs the legacy OCPP 1.6J SetChargingProfile urgently, and has no time to implement or change a running installation, here's a little "hack"

Due to the open and transparent architecture of Citrine, you can just blow the missing message in the RabbitMQ and it will be propagated to the Charger:

I used this little script

// publish-ocpp16-action.js
// npm i amqplib
const amqp = require("amqplib");

const RABBIT_URL = process.env.RABBIT_URL || "amqp://guest:guest@yourAMQPhost:5672";
const STATION_ID = process.env.STATION_ID;
const ACTION = process.env.ACTION;
const PAYLOAD_JSON = process.env.PAYLOAD_JSON;

const TENANT_ID = Number(process.env.TENANT_ID || "1");
const STATE = Number(process.env.STATE || "1");
const PROTOCOL = process.env.PROTOCOL || "ocpp1.6";

// Publish either to station queue (default) or an exchange (optional)
const TARGET_QUEUE = process.env.TARGET_QUEUE; // default rabbit_queue_1:<stationId>
const TARGET_EXCHANGE = process.env.TARGET_EXCHANGE; // if set, will publish to exchange instead
const TARGET_ROUTING_KEY = process.env.TARGET_ROUTING_KEY || "";

function newCorrelationId() {
  return String(Date.now());
}

function mustGet(name, value) {
  if (!value) throw new Error(`Missing required env var: ${name}`);
  return value;
}

function pretty(obj) {
  return JSON.stringify(obj, null, 2);
}

function printPublishPlan({ target, bodyObj, props, buf }) {
  const size = buf.length;

}

(async () => {
  mustGet("STATION_ID", STATION_ID);
  mustGet("ACTION", ACTION);
  mustGet("PAYLOAD_JSON", PAYLOAD_JSON);

  let payloadObj;
  try {
    payloadObj = JSON.parse(PAYLOAD_JSON);
  } catch (e) {
    throw new Error("PAYLOAD_JSON is not valid JSON.");
  }

  const correlationId = process.env.CORRELATION_ID || newCorrelationId();
  const timestamp = new Date().toISOString();

  // Envelope based on the CitrineOS router message you captured
  const bodyObj = {
    origin: "csms",
    eventGroup: "router",
    action: ACTION,
    context: {
      stationId: STATION_ID,
      correlationId,
      tenantId: TENANT_ID,
      timestamp,
    },
    state: STATE,
    protocol: PROTOCOL,
    payload: payloadObj,
  };

  // Headers (mostly strings like your sniff)
  const headers = {
    action: ACTION,
    correlationId: String(correlationId),
    eventGroup: "router",
    origin: "csms",
    state: String(STATE),
    stationId: STATION_ID,
    tenantId: String(TENANT_ID),
    timestamp: timestamp,
    protocol: PROTOCOL,
  };

  const buf = Buffer.from(JSON.stringify(bodyObj), "utf8");

  const props = {
    contentType: "application/json",
    deliveryMode: 2,
    headers,
    messageId: `poc-${correlationId}`,
    correlationId: String(correlationId),
  };

  // Print what we will publish
  const target = TARGET_EXCHANGE
    ? `exchange=${TARGET_EXCHANGE} routingKey="${TARGET_ROUTING_KEY}"`
    : `queue=${TARGET_QUEUE || `rabbit_queue_1:${STATION_ID}`}`;

  printPublishPlan({ target, bodyObj, props, buf });

  const conn = await amqp.connect(RABBIT_URL);
  const ch = await conn.createChannel();

  if (TARGET_EXCHANGE) {
    await ch.checkExchange(TARGET_EXCHANGE);
    ch.publish(TARGET_EXCHANGE, TARGET_ROUTING_KEY, buf, props);
    console.log(`✅ Published to ${target}`);
  } else {
    const queue = TARGET_QUEUE || `rabbit_queue_1:${STATION_ID}`;
    await ch.checkQueue(queue);
    ch.sendToQueue(queue, buf, props);
    console.log(`✅ Published to ${target}`);
  }

  await ch.close();
  await conn.close();
})().catch((e) => {
  console.error(e);
  process.exit(1);
});

and started it with this command:

#!/usr/bin/env bash
set -euo pipefail

# ===== Connection =====
export RABBIT_URL="amqp://guest:guest@yourAMQPhost:5672"

# ===== Target charger =====
export STATION_ID="stationID"
export TENANT_ID="1"
export STATE="1"
export PROTOCOL="ocpp1.6"
# Optional: override if you don't want default rabbit_queue_1:<stationId>
# export TARGET_QUEUE="rabbit_queue_1:${STATION_ID}"

# ===== Action =====
export ACTION="SetChargingProfile"

# ===== Charging profile params =====
# IMPORTANT: set transactionId to the currently active transaction on the charger/connector.
# connectorId must match the connector you want to limit.
export PAYLOAD_JSON='{
  "connectorId": 1,
  "csChargingProfiles": {
    "chargingProfileId": 101,
    "stackLevel": 0,
    "chargingProfilePurpose": "TxProfile",
    "chargingProfileKind": "Relative",
    "transactionId": 7,
    "chargingSchedule": {
      "chargingRateUnit": "W",
      "chargingSchedulePeriod": [
        { "startPeriod": 0, "limit": 10000 }
      ]
    }
  }a
}'

node publish-ocpp16-action.js

The power requirement can actually also be a negative number if you have a bidi charger

[StefanRiedAV]

here's my PR for the working implementation
citrineos/citrineos-core#528