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I have a CAN bus with one node acting as a master and several slaves. All nodes have a independent power supply. Is it possible to switch all nodes off and on from the master? The switch off can be realized over a CAN-message. But is there a way to power on Nodes over the CAN bus? It would be okay to switch all slave nodes on by powering up the bus and switching all off by commands to switch them all on again later.

switching can-nodes over can

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  • \$\begingroup\$ I don't understand your schematic. Are you saying that you are powering the transceivers directly from a battery with no regulator in between? And what is the weird connection between battery and CAN H+L? What's those switches supposed to be? MOSFETs? \$\endgroup\$ – Lundin Nov 9 '16 at 12:13
  • \$\begingroup\$ @Lundin In the end there is a regulator in between. The graphic is a simplification. The switch at the slave nodes is the question. "Is there a way to switch independent nodes via CAN on and off?" \$\endgroup\$ – Stani Nov 9 '16 at 12:55
  • \$\begingroup\$ And I asked you what is the switch? Is it an actual physical switch like you have drawn, or is it a MOSFET, BJT transistor, some switch IC or what? \$\endgroup\$ – Lundin Nov 9 '16 at 13:45
  • \$\begingroup\$ @Lundin It shall be an electrical switch. The Question is if there is a way to toggle this switch via can to control the node. \$\endgroup\$ – Stani Nov 9 '16 at 14:12
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Instead of switch on or off a node, Sleep function of the node MCU can be an option. If you send a specific message from master then the receiver can put itself into Sleep mode. Then if you send another message, it can wake up. But this requires a detailed programming.

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  • \$\begingroup\$ That is an option but better would be an total switch off since the slave nodes are powered by a battery wich should not be deeply discharged. So if the battery power of the node is low it shall be switched off completely. \$\endgroup\$ – Stani Nov 9 '16 at 11:24
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    \$\begingroup\$ @Stani In that case, You will need another node which can control switches for Nodes... Which is not a practical way! Better to use Sleep mode \$\endgroup\$ – Swanand Nov 9 '16 at 12:16

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