New in the Community? Get started here

Schneider Electric Exchange Community

Discuss and solve problems in energy management and automation. Join conversations and share insights on products and solutions. Co-innovate and collaborate with a global network of peers.

Register Now
Knowledge Base
Showing results for 
Search instead for 
Did you mean: 
Discover the Exchange Community Top members of July 
Discover the latest features your community has to offer: register to the webinar here

Field bus (Infinet or MSTP) will shut down as soon as device is connected


Infinet/MSTP was running fine until a device was added or replaced, after wiring in the new device it brings down the Infinet/MSTP field bus when powered up, disconnecting the new device from the bus makes the bus resume operation.

When the new device is connected the green (RD) LED goes solid instead of blinking and all communications to all devices on the bus stops, in some cases the master controller will reset.

Product Line

Andover Continuum, EcoStruxure Building Operation


  • Infinet devices
  • i2s
  • MSTP devices
  • b3s


Power lines reversed.

Continuum field devices (i1s, i2s and b3s) have their RS-485 communication lines connected to ground via an isolator as seen in the diagram below, if the LIVE and GND lines are inverted then LIVE is connected to the 485 communication lines instead of GND.

This will make the field bus electrically unable to communicate and in some scenarios can even cause hardware damage.


When powering 24VAC  devices off the same transformer make sure to continue the wiring chain LIVE to LIVE and GND to GND.

Tags (2)
No ratings