PRECITEC CHRocodile CLS0.2, Руководство по эксплуатации

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5.2 Detailed Commands Description
5.2.1 DNLD Command
Short description:
Clients use this command to request a spectrum from the device. Since acquiring spectra can
take up several sample periods, a DNLD request from the client causes the device to first
respond with a DNLD response that does not contain any spectrum data. It just acknowledges
the request. Later, when the spectrum is available, the device sends one or more command
packets (“update” packet) containing the real spectrum data. Data packets may arrive in the
meantime, i.e. between the response and the spectrum. Update packets are structured exactly
like command (response) packets, only with the “update” flag set.
Currently, DNLD command does not function for ASCII command connections.
5.2.2 ETR Command
This command groups several functions related to encoder triggering.
WARNING: The settings will not be saved in the EEPROM by the $SSU command.
The encoder trigger is implemented as a state machine. In the idle state, it waits for the
encoder counter of the selected axis to pass the start position (in either direction)
where it generates the first trigger event. Then the trigger interval value is added to the
current position and when this position is reached, the next trigger event is generated.
This step is repeated until the stop position is encountered.
The generation of trigger events is now stopped. If Triggering during return movement
is selected, the state machine waits for the stop position to be passed once again and
generates trigger events similarly to the forward movement (the trigger interval is now
subtracted instead of added) until the start position is reached. The state machine then
goes back to the idle state. If no Trigger during return movement is selected, the state
machine waits for the start position to be passed over (during return movement) and
then passes to the idle state.