Issue
Poor communications, communications failure or packet being corrupted
Product Line
Andover Continuum,EcoStruxure Building Expert,EcoStruxure Building Operation,Satchwell MicroNet,Satchwell Sigma,TAC INET,TAC Vista
Environment
- Communications networks, BACnet MSTP, LON FT10, Infinet, Modbus RTU, Ethernet
- EMC (Electromagnetic compatibility)
- VSD Variable Speed Drive, VFD Variable Frequency Drive, Inverter Drive
Cause
Electrical Interference from Inverter (variable speed drives or VSD)
Radiated or Induced RFI (Radio Frequency Interference)
Resolution
A VSD has the potential to create a large amount of electrical noise, to avoid causing issues it is vital they are installed as the manufacturer's instructions. (Other devices also have this potential)
Our systems are often used to control VSDs on fan motors, so if poor communications is found during the commissioning process, then try stopping all the fans in the area then re-testing the communications.
A recent example was seen where LON FT10 communication was working ok until some VSDs were started, at this point LON devices and Object went offline intermittently.
When all the VSDs were stopped the communication become completely stable.
It was then possible to find which VSD was causing the problem and correct the VSD installation.
In this case a LON analyzer would also have helped diagnose the issue.
