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"Negative Acknowledgement" when Reading Registers in the EGX100 Diagnostic Webpage when communicating to devices using PowerLogic Protocol - Protocol Errors on Serial Port in Diagnostics Statistics

The user receives a "Negative Acknowledge" message when attempting to read registers through the EGX100 Read Device Registers webpage. This occurs when reading registers from devices connected that use PowerLogic protocol. These devices include Series 100, 200, 2000 Circuit Monitors (CM2000, CM100, CM200), Series 600 Power Meters (PM600), Digital Relays (DR), and PowerLogic Interfaces (PIF3 and PIF85).


This is a list of possible causes but are not limited:

- attempting to read a register which does not exist in a particular device

- incorrectly configured dipswitch biasing on the EGX100 RS485 port


Check to see that the correct register is being read and that the dipswitches are configured according to the diagram above.

  • Date Created: May 29, 2008
    Last Revised: June 26, 2008
    Original Author: AV
    All content © 1992-2008 Schneider Electric
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