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4.2.5 Extended Measurement Range
The measurement range in the normal start-stop operation mode is 10.7µs (R212) and 40µs (R312 & R322).
The SC-TDC-1100 devices come with an extended measurement range functionality, to cope with larger
measurement ranges .The reference measurement is switched on/off within the tdc_gpx3.ini file.
The corresponding entry in the tdc_gpx3.ini file is:
ReferenceMeasurement = X
X is either NO or YES.
The default setting is NO
.
X = NO switches the reference measurement off.
The extension of the measurement range is working in such a way, that start signals are internally counted
up to extend the global time axis. For this the TDC is operating with its internal start signal, while the
external start signal is given to one of the stop signals in addition to the regular stop signals. Time results
are then provided as reference results of the external start and the stop signals on basis of the internal
extended time axis.
Therefore one of the stop inputs of the TDC must be used to apply the external start signal, which reduces
the number of available stop inputs by one.
Additional changes in the tdc_gpx3.ini file must be made for the extended measurement range to function.
The corresponding entries in the tdc_gpx3.ini file to be made are:
Ext_Gpx_Start = NO
StartCounter = NO
StartPeriod = 0
It must also be defined in the tdc_gpx3.ini file which of the stop input channels provide the reference
signal for calculating the times of the other stop signals. The need of defining the reference channel also
allows to define different reference channels for the different stop channels.
The corresponding entry in the tdc_gpx3.ini file is:
ReferenceChannelX = Y
X corresponds to the specific number of the stop channel.
Y
defines the specific stop channel which is
used for stop channel X as reference channel. The channel numbering starts with 0. Single channels can
also be switched off in case that signals on that channel should not be measured itself, but only be used as
reference channel. In this case X can be set to -1.
The reading of this entry is: “the reference of channel X is channel Y”.
SC-TDC-1100 Series Manual | Surface Concept GmbH
