Soluciones y Tecnologías de Control Embebido S.A.P.I. de C.V.
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Trigger control via USB
The interconnection of the previous section allows shots to be made at the user's request
by activating the "Soft-Trigger" button, but if said shots are to be made repeatedly, with a certain
frequency of the flash lamp being triggered, then it may be convenient for the control The DG-
3O1I is made from a PC, so that a control program repeatedly sends the trigger command via USB.
Fig. 28. Lamp control, Q-Switch and spectrometer from DG-3O1I-17 connected to a PC for repetition of the
trigger command with programmable frequency
The DG-3O1I-17 equipment is recognized by the PC via the USB bus as a serial port, for example
COM3 (the port number may vary and is automatically assigned by the PC).
The serial command (via USB) is to send the DG-3O1I-17 the ASCII character "S" followed by a
return character CR (decimal value 13). For example, in LabView, the section of code to send the
trigger command would read as follows:
Fig. 29. Serial trigger command formed in LabView
By sending this command repetitively and at regular time intervals, a certain flash lamp and Q-
Switch firing frequency could be configured (using the configuration from the equipment's own
display). Serial configuration corresponds to a speed of 9600 bps, 8 data bits, no parity and one
stop bit.