Assume that each heart beat requires a Publish event.

coupler/opc-ua-server/cli.h

@@ -149,6 +149,7 @@ void handleCLI(int argc, char **argv) {
     I2C_VIRTUAL_MODE = arguments.mode;
     I2C_BLOCK_DEVICE_NAME = arguments.device;
     HEART_BEAT_INTERVAL = arguments.heart_beat_interval;
+    PUBLISHING_INTERVAL = HEART_BEAT_INTERVAL; // we assume that each heart_beat leads to a publish event
     HEART_BEAT_TIMEOUT_INTERVAL = arguments.heart_beat_timeout_interval;
     NETWORK_ADDRESS_URL_DATA_TYPE = arguments.network_address_url_data_type;
     USERNAME = arguments.username;

coupler/opc-ua-server/keep_alive.h

@@ -27,7 +27,7 @@ static int HEART_BEAT_TIMEOUT_INTERVAL = DEFAULT_HEART_BEAT_TIMEOUT_INTERVAL;
 unsigned int HEART_BEAT_ID_LIST[] = {0, 0, 0, 0, 0, 0, 0, 0};
 
 // the interval for publishing messages$
-const int PUBLISHING_INTERVAL = 10;
+static int PUBLISHING_INTERVAL = 10;
 
 // a hard coded writer group, data set and publisher ID$
 // (should be same for publisher / subscriber)$

coupler/opc-ua-server/keep_alive_subscriber.h

@@ -217,7 +217,7 @@ static UA_StatusCode addSubscribedVariables(UA_Server *server, UA_NodeId dataSet
         /*monitor variable*/
         if (ENABLE_HEART_BEAT_CHECK) {
           UA_MonitoredItemCreateRequest monRequest = UA_MonitoredItemCreateRequest_default(newNode);
-          //monRequest.requestedParameters.samplingInterval = 100.0; /* 100 ms interval */
+          monRequest.requestedParameters.samplingInterval = PUBLISHING_INTERVAL;
           UA_Server_createDataChangeMonitoredItem(server, UA_TIMESTAMPSTORETURN_NEITHER,
                                                   monRequest, NULL, dataChangeNotificationCallback);
         }