This is likely caused by Line Noise. To fix this, check the following:
- Verify that all units have proper RS485 connections and that no stubs are used on the RS485 lines preventing thorough data updates;
- Verify that all units have proper Beldon RS485 cabling;
- Verify that there are no in ground- loops (cable shield should be tied to one end only and that no shields are connected to the middle RS485 connector;
- All communication grounding; cable shields; are one-point tied to a quiet ground point;
- Verify that all communication hubs (for large aggregate communication equipment points) are mutually tied together with the appropriate AWG cable (14-12 AWG/Stranded) to a common building bond point as per NEC part 68 requirements;
- Ensure that all power grounds for these aggregate Hubs are tied to one common neutral point;
- Ensure that there are no stubs feeding from the Bus line;
- Verify that the RS485 lines are not too long (maximum of 1.2KM (for two nodes)- too <500M for more than 15 nodes);
- Verify that End-Of-the-Line ( EOL) connectors are connected at either end to reduce line noise when transmitting; and
- Verify that the IP network has no through-put issues.
Comments are closed.