Stf 8300M and external trigger

Discussion in 'STF Series CCD Cameras' started by Murat, Apr 13, 2017.

  1. Murat

    Murat Standard User

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    Thanks for the reply Doug

    "Although the user manual for the STF-8300M doesn't talk about triggering, the latest STF-8300M firmware and drivers do support external trigger. The application software does also have to support it. I know MaxIm DL does.
    Trigger I/O is on the I2C port. Although it's not in the STF manual, it's described in the STT manual on page 41:
    http://diffractionlimited.com/wp-content/uploads/2016/04/stt_manual_080112b.pdf"

    Tell me, now, please, what are the signal parameters for the opening of the shutter?

    Best regards,
    Murat
     
  2. Doug

    Doug Staff Member

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  3. Murat

    Murat Standard User

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    Dear Doug!
    According to your instructions, I updated the driver and firmware for my camera STF-8300M. I am giving the external trigger signal to the input according to the scheme on page 41 (ground - pin 5, signal - pin 6). However, the camera does not work by the signal of the external trigger. Tell me, please, what could be wrong?
     
  4. Murat

    Murat Standard User

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    Everything is OK!
     
  5. Doug

    Doug Staff Member

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    You have to set the software to use external trigger mode, and then start an exposure from the software. Only then will the trigger work.
     
  6. Murat

    Murat Standard User

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    Dear Doug,
    Tell me, please, and what should be the pulse duration? I have a pulse of +5 volts, 8 microseconds. Sometimes the camera does not immediately trigger the pulse. There is a delay.
     
  7. Doug

    Doug Staff Member

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    Make sure you have the latest firmware installed in the camera. The original version had too much delay, so we improved it.

    Pulse should probably be a millisecond to be safe.
     
  8. Murat

    Murat Standard User

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    Dear Doug,
    I'm sending a signal to the camera for a few milliseconds. The camera is triggered by this signal. I measure the gate opening delay and this time is about 100 ms. However, sometimes there are cases when the camera does not respond to the signal, but operates "at its discretion." What could be the reason for this?
     
  9. Doug

    Doug Staff Member

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    Did you make sure you have the updated firmware? Doesn't sound like it.
     
  10. Murat

    Murat Standard User

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    I have the latest firmware version. I am sure about that. Today I updated everything again. The signal 1 pps comes to the camera. This signal is linked to the scale UTC. For example, the signal came in at 12: 30: 25,000 (Exposure start time). When the camera is triggered as it should, the shutter release time is 12: 30: 25.100 (Actual exposure start time). Sometimes the camera gives different values Actual exposure start time: 12: 30: 25.450, 12: 30: 24.720 and so on. Can you explain why this happens? Can where that contact is absent? Maybe something happened in the camera circuit? Can you show a circuit for triggering the camera shutter by an external signal?
     
  11. Murat

    Murat Standard User

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    Dear Doug,
    Can the temperature affect the operation of the camera from an external trigger? Yesterday the camera at external trigger did not react (the temperature was about 8 degrees Celsius), but today the camera operates from an external trigger normally (temperature about 15 degrees Celsius).
     
  12. Doug

    Doug Staff Member

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    No, the temperature would not have an effect. Are you sure you don't have an intermittent electrical connection? Did you connect both the trigger input and ground?
     
  13. Colin Haig

    Colin Haig Staff Member

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    Other thought - you mention "1pps" above - are you trying to send a trigger every seccond ? Of are you gating your trigger to be accurate to a 1pps GPSDO or some other timestamp?
     
  14. Murat

    Murat Standard User

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    Yes, I send a signal "1pps" from the GPS receiver to the camera every second. This is necessary to accurately bind to the time scale UTC with an accuracy of several milliseconds.
    If I start the camera without an external trigger, the opening time of the shutter is unknown and it is not stable.
    Sometimes it happens that I see on the oscilloscope on the connector to the camera a normal signal (+5 Volts, 50 ms), but the camera does not work. Sometimes it happens that the camera is waiting for an external trigger, if it is absent, sometimes the camera does not wait for an external trigger, but it works, although there is no real external trigger.
     
  15. Colin Haig

    Colin Haig Staff Member

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    I'm wondering if the exposure time, shutter latency, download time, and recovery tme are > 1 second. In other words, maybe the camera triggers on the first pulse from the GPS, and then another pulse arrives before it has finished cycling, so that one may be ignored or the camera may trigger after it has recovered.
     
  16. Doug

    Doug Staff Member

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    Colin is right, a cycle time of 1 second is a little fast. It is comparable to the download time of the camera, unless you are using subframing or binning.
     

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