knt2009 Posted February 14, 2015 Report Share Posted February 14, 2015 Hello, I am using a RS 485 MODBUS communication to controll the speed of the frequency converter (Commander SK from EMERSON). I did suceed to establish the communication between the PLC and the frquency converter, but afterwards I was not able to downlaod a new PLC program to the controller. Any communication between the programing PC and the PLC was no more possible. Can somebody give me some advise what to do? I was thinking about hardware reset or something like this. PLC type M91-2-R2C best regards, Miha Quote Link to comment Share on other sites More sharing options...
AlexUT Posted February 22, 2015 Report Share Posted February 22, 2015 Hi, Default communication settings for U90Ladder are 9600, 7, N, 1. MODBUS require 9600, 8, N, 1. Check if Break is disabled or not. Break signal reset communication settings to default to allow U90Ladder communication. You can change communication settings to 9600, 8, N, 1 and check again. Or enter Info mode and change to "SYSTEM->STOP ?" and stop program. This allow to restore communication. Quote Link to comment Share on other sites More sharing options...
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