#PROFINET
1 articles
Network / VPN
TCP Reaches State 4 but SentBytes Stays at 0 on Two PLCSIM Instances
I opened two PLCSIM instances so S7-1500 PLCs could communicate through TSEND_C and TRCV_C, but it did not work. I reported the wrong result twice because I had never measured anything. Only after adding diagnostic OBs to read STATUS and T_DIAG from the actual instances on both sides, along with a control link to a nonexistent partner, did I see that every failing link passed through the CPU's second PROFINET interface.