TroubleshootingCommunicationTroubleshooting communication errorsIf a communication error occurs, check the following:1. Check that the gateway and the ventilation units are powered2. Check whether the Data+ and the Data- wires have been switched3. Check that each ventilation unit has its own unique Modbus address in accordance with the templateprovided4. Check that there is activity on LED1 at Ethernet plug 2 on the gateway (the activity must be regular)5. Check that the gateway is connected to the internet (can you access the internet with a computervia the Ethernet cable for the gateway)6. Check that all ventilation units are grounded correctly.Modbus networkData+ and Data- refer to ground in each individual control system, which, through the control system,is connected to protective earthing (PE). The voltage between Data+/Data- and the reference (PE) iscalled the common mode voltage. The common mode voltage / the potential difference betweenground points must not exceed 5Vrms AC and DC.At the gateway, ground connected up to PE ground and. wired to each junction box, but as a rule are notconnected to the control, as this has its own PE ground connection. Check the voltage difference fromthe grounded shield to the frame of the steering. If it exceeds 5Vrms, check if the controller isconnected to PE ground via the supply cable. If the voltage is not lowered below 5Vrms via the groundwire, the frame wire is connected from the cable between the connection box and the controller. Nowthe screen and the power line will provide the potential equalization between the control and thegateway. The frame and screen are brought together at the gateway and in the junction box in order tohandle a slightly larger ground loop current.Nilan MultiLink (English) BY NILAN15