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Monitoring Configuration
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The Overview device has an autogenerated scene for tuning the
monitoring configuration. An example is shown in :numref:`Fig. %s <fig-monitoring_config>`.
The monitored variables are grouped according to the device node they belong to 
(i.e, *Inputs*, *Internals*, *Outputs*).

.. _fig-monitoring_config:

.. figure:: _images/vars_in_config_scene.png
   :scale: 50 %
   :align: center

   Scene to show which properties are disabled from the monitoring by the users.

To include a variable to a monitoring Overview it should be added (by CTRLS) to the
hardcoded configuration of that device, along with the proper monitoring type class
for that. The monitoring classes currently available in the overview device are described
here below together with their available settings:

* *AnalogueElement*:

  monitors a float to be above a *Signal Threshold* value; tolerance to this
  condition is provided by allowing a deviation down to a an absolute value
  below (*Max Negative Deviation*) the threshold. The deviation is given in
  as percent value of the threshold,

* *AdcElement*:

  similar to the *AnalogueElement* case, except that it monitors the maximum signal
  of an array,
 
* *AnalogueAbsRangeElement*:

  monitors a float to be above a *Signal Threshold* value; a tolerance to this
  condition is provided by allowing deviations up to an absolute value
  above (*Max Positive Deviation*) and below (*Max Negative Deviation*) the threshold,

* *AnalogueRangeElement*:

  similar to the *AnalogueAbsRangeElement* case, except that the deviation range is
  given as percent of the threshold value,

* *UIntegerElement*, *DoubleElement*, *StringElement*:

  monitors an unsigned 64-bits integer, double or string to have a configurable
  *Reference* value,
  
* *UIntegerLimitsElement*:

  monitors an unsigned 64-bits integer to be within configurable
  "Min Value" and "Max Value" values,

* *BooleanElement* (*FalseBooleanElement*):

  monitors a device variable which is expected to be True (False),

* *StateElement*:
  
  monitors a device state which is expected to be in a typical running condition
  (at the moment, device class dependent).

Analogue values are typically fluctuating due to different kind of conditions,
such as due to the environment (e.g. thermal noise in the acquisition line) or
to the physical process generating the signal (as for the amplified pulse-probe
laser). To avoid fluctuations giving rise to warnings, moving averages are considered
for that kind of variables. The size of the those average samples
*Moving Average Size* is tunable by the users up to 20. Setting the size to one
disables the running avarage feature.

It is the responsability of the user to choose the proper monitoring class for
a specific variable, and to tune its corresponding settings.
 
In the configuration scene, for each variable its quality state Boolean *isOk*
is displayed close to the corresponding device Id, as well as its key name in the
monitored device.
By default its monitoring is enabled, but the user has the possibility directly
from the scene (or from the device configuration editor) to disable it by unsetting
the corresponding *Is Monitored* Boolean (*isMonitored* key).
Every change of this Boolean results in the immediate update of the list of not
monitored properties. Disabling the monitoring of a property turns immediately
its *isOk* state to True.

A change of the Boolean *isOK* triggers the evaluation of the grouping node
state it belongs to; the node *isOK* state will be False if at least one
monitored variable in the node is in a bad state.
A change of the node *isOk* value triggers the evaluation of the
device *isOk* Boolean, as described in :numref:`Fig. %s <fig-isok_propagation>`:

.. _fig-isok_propagation:

.. figure:: _images/isOk_propagation.png
   :scale: 50 %
   :align: center

   Evaluation of the Overview device monitoring Boolean *isOK* state.


At the bottom of the scenes two slots (buttons) are present to help configuring the
monitoring:

* *Update References*

  The references are updated reading from the running system the current
  value of the monitored properties; e.g., when monitoring a temperature sensor
  (via the class *AnalogueRangeElement*) the current reference value will be set
  as the new reference,

* *Save Config Log*

  The monitoring configuration is saved online, and whenever the Overview device restarts
  that configuration will be set back to it.

In the device configuration editor of the main Overview device (and also
directly in the LAS main overview scene) the extra slots
*Save System Config* and *Update System References* save the online configuration
and retrieve the references recursively through the entire system,
respectively.

In the LAS environment the so-called *slave* experiment in the two-laser-beamlines
systems is the experiment which does not receive the pulse-probe laser synchronized to
work with the XFEL x-rays; when this is the case
some specific devices will not operate within the nominal running 
parameter values (e.g. having only background signal in the diagnostic cameras),
and thus the corresponding Overview devices will have the state *isOk* unset.
In this situation those devices have to be disabled (enabled) in the monitoring when the
instrument switch from *master* to *slave* (and vice-versa) operational mode is done
(typically in the morning and the evening). This is implemented automatically by the Overview
device after inserting (by CTRLS) those devices in a special list in the Overview configuration.