Is there a way to tell the history manager to listen on a e.g. serverTimestampChange? I did only find the addDataChangeListener() for the UaVariable, so how could I track values in the history, where the data hasn’t changed?

We use the codegenerator. How can we force a reset of the sourceTimestamp there?

The idea is to have several values collected at a fixed sampling rate. E.g. 30ms. If one value doesn’t change in some timespan, we nevertheless want a datapoint because elseway the time-dimension is not constant between different collected values.

Does anybody have a solution for this?

Hi Bjarne,
sure:
private final ScheduledExecutorService simulator = Executors
.newScheduledThreadPool(Runtime.getRuntime().availableProcessors());
simulator.scheduleAtFixedRate(this, 0, 25, TimeUnit.MILLISECONDS);

in the run() method, which is called every 25 milliseconds:
updateAxisAngles();
updateTorques();

The method looks like:
public void setAllAxisAngle(JointPosition axis) throws StatusException {
Axis axis = AddressSpace.getAxisNode();

// Be careful not getting an out of bounds error
ArrayList newValues = new ArrayList();

for (int i = 0; i < axis.getAxisCount(); i++)
newValues.add(axis.get(i));

Double[] newValuesAr = new Double[newValues.size()];
axis.setValues(newValues.toArray(newValuesAr));
}

updateTorques works the same

and axis.setValues is generated by the jave codegenerator. I tried to change the implementation as explained in the last post, but without success. In the end i get a different number of axis and torques…

Thanks,
lg manu

Hi,
ok on client side I use python-opcua. And i do a

for node in nodes_to_watch:
node_history = node.read_raw_history(starttime=starttime, endtime=endtime)

Start and endtime do not change. And finally I get a different number of history elements for the two nodes. I would agree with you, if this would just be a difference of one, then maybe we were reading exactly between writing the one and the other node on server side. But when recording longer time, the numbers diverge by 200 or so.

lg

Hi Bjarne,
The requirements for the history data:
– It must not survive a restart
– We have to collect data from a device at a fix time interval e.g. 25ms. For every timestep several nodes are written. E.g. one node (an array of 7 axis values) another node an array of (6 force values).

The code is mainly from the example server. So at the history manager listener there is for onReadRaw:

ValueHistory history = variableHistories.get(node);

if (history != null) {
List values = new ArrayList();

int firstIndex = continuationPoint == null ? 0 : (Integer) continuationPoint;

Integer newContinuationPoint = history.readRaw(startTime, endTime, numValuesPerNode.intValue(),
returnBounds, firstIndex, values);
historyData.setDataValues(values.toArray(new DataValue[values.size()]));

return newContinuationPoint;
}

return null;

In ValueHistory we have:
public Integer readRaw(DateTime startTime, DateTime endTime, int maxValues, boolean returnBounds, int firstIndex,
List history) {
int i = 0;
boolean startTimeDefined = startTime.compareTo(DateTime.MIN_VALUE) > 0;
boolean endTimeDefined = endTime.compareTo(DateTime.MIN_VALUE) > 0;

if (startTimeDefined || !endTimeDefined)
for (DataValue value : values) {
DateTime t = value.getSourceTimestamp();

if (t == null)
t = value.getServerTimestamp();

final int compareToEnd = endTimeDefined ? t.compareTo(endTime) : -1;

if ((compareToEnd > 0) || (!returnBounds && (compareToEnd == 0)))
break;
else {
final int compareToStart = t.compareTo(startTime);

if ((compareToStart > 0) || (returnBounds && (compareToStart == 0))) {
if (i >= firstIndex)
history.add(value);

i++;

if (history.size() == maxValues)
return i;
}
}
}
else
for (int j = values.size() – 1; j >= 0; j–) {
DataValue value = values.get(j);
DateTime t = value.getSourceTimestamp();

if (t == null)
t = value.getServerTimestamp();

final int compareToEnd = t.compareTo(endTime);
if ((compareToEnd > 0) || (!returnBounds && (compareToEnd == 0)))
continue;
else {
if (i >= firstIndex)
history.add(value);

i++;

if (history.size() == maxValues)
return i;
}
}

return null;
}

and readAtTimes() is:
public DataValue[] readAtTimes(DateTime[] reqTimes) {
if (reqTimes == null)
return null;

DataValue[] values = new DataValue[reqTimes.length];

for (int i = 0; i < reqTimes.length; i++) {
DateTime t = reqTimes[i];

// Stepped interpolation used to get values
DataValue v = getValue(t);
values[i] = new DataValue(v == null ? null : v.getValue(),
v == null ? new StatusCode(StatusCodes.Bad_NoData) : v.getStatusCode(), t, UnsignedShort.ZERO, null,
null);
}

return values;
}