MHzDAQp01Channel mean and stddev values as counters

The attributes MeanValue and StdDevValue of the MHzDAQp01Channel class can be use as counters in Sardana.

The entry in the online.xml file looks like:

<device>
 <name>mhzdaqmean1</name>
 <tags>expert</tags>
 <type>counter_tango</type>
 <module>mhzdaqp01</module>
 <device>p01/mhzdaqp01channel/eh2.01/meanvalue</device>
 <control>tango</control>
 <hostname>haspp01eh2:10000</hostname>
</device>

<module> has to be mhzdaqp01</module> <device> has to contain not only the name of the Tango device but also of the Tango attribute that wants to be read (MeanValue or StdDevValue). The rest of the fields follow the general instructions for any other entry.