4 BASIC CONCEPTS
4.4 Adjustment auto function
In the
PICOSCALE auto functions are complex configuration processes that, once triggered, au-
tomatically perform a sequence of internal routines to optimize the system performance. The
adjustment auto function performs certain procedures to achieve high accuracy of position data
and must be run once before measurement. It has three states:
• Disabled
By default the auto function is disabled.
• Manual Adjustment
In this state you have to adjust the targets that reflect the laser back into the sensor head
in order to get the highest possible signal quality. Once satisfied, the user must start the
automatic adjustment routine to complete the adjustment.
• Automatic Adjustment
In this state the device performs internal signal optimization routines to improve the accu-
racy of the position data. After this procedure, the activated channels will generate valid
position data and you can start measuring.
4.5 Events
In some situations events might occur that require further attention or reactions by the user.
To avoid that the status of the device has to be permanently checked, the
PICOSCALE offers a
notification system that you may configure to your needs. By default, the most important alerts
are enabled.
For example, a beam interrupt event is produced if the probe beam is disturbed such that the
signal quality has fallen below a certain level. If at some point the signal quality is sufficiently high
again, a beam restored event is sent. This information is important as you have to check if the
position data are still valid. Within the Advanced Trigger module, this event can be used as trigger
source which can be forwarded to a GPIO pin, for example. This way, you may react to unforeseen
incidents in the experimental setup and stop moving parts, for example.
4.6 System filters
Most
PICOSCALE data sources are subject to low pass filtering before they are provided to other
internal modules. Compared to depricated
PICOSCALE firmware versions
1
, this has the advan-
tage that the following modules can operate with filtered data:
• Calculation System. Data are filtered before they can be processed in the module
• Advanced Trigger. Triggers can be set up to react on filtered data
• Digital Differential Interface. Filtered data can be output via the AquadB or SD protocol
1
In previous firmwares – older than 1.4.3 – the filters were implemented in the stream generator module. Therefore, only
data that were actually streamed via USB or Ethernet were subject to low pass filtering. If data sources were used within
the Calculation System, Trigger System etc or output via AquadB interface, the data were suffering increased noise.
26
PicoScale User Manual
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