I am trying to read some tags using Rslinx server thru DH+ in microsoft excel. For this I have configured a topic for that particular PLC(AB PLC-5). I have kept the DDE configuration as told in the RSlinx manula for DDE support. I am able to read the data though at times I miss the data and the PLC communictaion is broken(This is shown as a red X mark over the PLC). what can be wrong with this. Is there anything to be taken care of while configuring the DDE topic for this. Please suggest a solution to this. It is urgent for me.