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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Local Node Slave not starting heartbeat","articleBody":"Hello,\n\nI am finding an issue, where, my master, on the startup, creates the network, adds the node, etc. and then, when I pass from INITIALIZING, to PRE-OPERATIONAL state, the slave, doesnt begin the heartbeat. I've checked the nmt module, and it should do It, but the thing is that It does not.\n\n```\n  def _startup(self, bms) -\u003e None:\n    bms.nmt.state = 'PRE-OPERATIONAL'\n    time.sleep(1)\n    bms.nmt.state = 'OPERATIONAL'\n    time.sleep(1)\n```\nHere, i set the bms (slave), state to pre-operational. The sleep is because if not, or it does not set it, or im not able to print it on the slave.  Adding the sleep, I can see that it sets it to PRE-OPERATIONAL. In fact, I see that it goes from initialized, to pre-operational, to operational. \n\nHowever, the thing is that when I check if I recieve the heartbeat, in the next code snippet, well, i don't receive It. Seems like the start_heartbeat method doesn't launch.\n```\n\n  def nmt_manager(self, bms) -\u003e None:\n    \"\"\"Monitoriza el estado del BMS mediante heartbeats.\"\"\"\n    logger.info(\"Iniciando monitorización de NMT (Heartbeat)...\")\n    while True:\n      try:\n        # Esperar heartbeat (timeout un poco mayor que el intervalo esperado de 1s)\n        bms.nmt.wait_for_heartbeat(timeout=2.0)\n        logger.info(f\"Heartbeat recibido. Estado BMS: {bms.nmt.state}\")\n      except Exception as e:\n        logger.warning(f\"No se ha recibido heartbeat del BMS: {e}\")\n\n```\n\nAlso, the heartbeat doesn't start, if, when starting the slave (a bms simulator, on the same machine), I do this:\n\n```\n    self.node = canopen.LocalNode(self.BMS_NODE_ID, self.DICT_EDS)\n    # Forzar el intervalo de heartbeat a 1000ms (1s) directamente\n    self.set_value(0x1017, 1, 500, \"Intervalo de heartbeat\")\n    self.network.add_node(self.node)\n```\n \n\nI know, that the start_hearbeat method is launched, either on passing from INITIALIZED from PRE-OPERATIONAL, or, via writing the producer heartbeat time(1017h). And i know that the write is a callback, but, doesn't work if the writing it's made before the node added to the network?\n\nTo make the heartbeat work, I had to do this:\n\n```\n  def _startup(self, bms) -\u003e None:\n    bms.nmt.state = 'PRE-OPERATIONAL'\n    time.sleep(1)\n    bms.sdo[0x1017].raw = 500\n    bms.nmt.state = 'OPERATIONAL'\n    time.sleep(1)\n```\n\nAdding the writing of the record 1017 on startup.\n\nMy setup is local, using vcan on my own linux. But can virtual channel seems to work perfectly fine.\n\nWriting this because I don't know if it's a bug, or I am wrong somewhere. ","author":{"url":"https://github.com/jfernandezbzigor","@type":"Person","name":"jfernandezbzigor"},"datePublished":"2025-12-04T10:17:41.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/620/canopen/issues/620"}