====== Raspberry Pi OPC DAQ ======

Create firewall service for OPC UA
   > sudo nano /etc/firewalld/services/opc.xml
      <?xml version="1.0" encoding="utf-8"?>
      <service>
         <short>OPC</short>
         <description>OPC</description>
         <port protocol="tcp" port="4840"/>
         <port protocol="tcp" port="4843"/>         
         <port protocol="tcp" port="51210-51211"/>   
         <port protocol="tcp" port="61210-61211"/>    
         <port protocol="tcp" port="62540-62553"/>                    
      </service>
   > sudo chmod 640 /etc/firewalld/services/opc.xml
   > sudo firewall-cmd --permanent --add-service=opc
   
Create firewall service for Node Red
   > sudo nano /etc/firewalld/services/nodered.xml
      <?xml version="1.0" encoding="utf-8"?>
      <service>
         <short>nodered</short>
         <description>Node Red</description>
         <port protocol="tcp" port="1880"/>
      </service>
   > sudo chmod 640 /etc/firewalld/services/nodered.xml
   > sudo firewall-cmd --permanent --add-service=nodered
   
=== Node Red ===
   > bash <(curl -sL https://raw.githubusercontent.com/node-red/linux-installers/master/deb/update-nodejs-and-nodered)
   > node-red-start