Intermittent RS485 Communication Loss in EM6436H Energy Meters

[Dineeesh]

We have installed 24 EM6436H energy meters connected in a serial loop via RS485 for data acquisition. Occasionally, some meters randomly go offline. The issue is temporarily resolved by disconnecting and reconnecting the auxiliary power supply. However, this workaround only restores functionality for a few days before the meters go offline again.

We are seeking a permanent solution to address this recurring communication issue.

[Charles_Murison]

Hello @Dineeesh ,

I would strongly recommend you reach out to your local technical support, se.com-> support->contact center -> Help and Contact Center.

Regards,

Charles

[Mehran_Mehrnia · Accepted solution]

Hi @Dineeesh 

As Charles mentioned, for further assistance, please reach out to the local tech support team.

Here are also some possible causes of the issue:

1- In Daisy chain wiring, please ensure Straight-line topology only. Loop or ring topology is not supported.

2- Since there are many devices, improper termination or biasing resistors can cause signal reflections or idle line voltage drift, leading to communication errors. 

To terminate a series, it is recommended to use a 120 W / 0.5 W resistor.
2- Long cable runs or poor shielding can introduce noise.
3- Please ensure all meters have unique Modbus addresses, and the same baud rate, parity, and stop bits across all devices and the master.

Best Regards,

-Mehran

L3 Expert Advanced metering