Add OPC-Ua nodes only if we have MOd-IOs configured over CLI.

coupler/opc-ua-server/server.c

@@ -89,16 +89,21 @@ static void addVariable(UA_Server *server) {
     /* 
      * Create all variables representing MOD-IO's relays
      */
+    int length = sizeof(I2C_SLAVE_ADDR_LIST) / sizeof(int);
+    if (length>=1) {
         // IC2-0
         addIntegerVariableNode(server, "i2c0.relay0", "I2C0 / Relay 0");
         addIntegerVariableNode(server, "i2c0.relay1", "I2C0 / Relay 1");
         addIntegerVariableNode(server, "i2c0.relay2", "I2C0 / Relay 2");
         addIntegerVariableNode(server, "i2c0.relay3", "I2C0 / Relay 3");
+    }
+    if (length>=2) {
         // IC2-1
         addIntegerVariableNode(server, "i2c1.relay0", "I2C1 / Relay 0");
         addIntegerVariableNode(server, "i2c1.relay1", "I2C1 / Relay 1");
         addIntegerVariableNode(server, "i2c1.relay2", "I2C1 / Relay 2");
         addIntegerVariableNode(server, "i2c1.relay3", "I2C1 / Relay 3");
+    }
 }
 
 /* Connect to variables to physical relays