Showing results for 
Search instead for 
Did you mean: 

Andor External Trigger Buffer Problem?

Hi there,


I am using Andor Zyla 5.5 model, but I think the problem I encountered is more general in high speed camera models. I used the following settings: Rolling Shutter, 0.005 Exposure time, External Trigger, Overlap ON, Full Frame(5M pixels). The problem exists as well in the example in Andor's labview SDK example(circular buffer, live mode) as well, fps is ~100.


When I use the Software Trigger, everything works fine. But when I use Internal or External Trigger, the Camera is "frozen" after  continuing display for a while. In fact the acquisition is 'Frozen' since same thing happens even if I removed anything other than download from the Then I looked into the acquisition loop, it seems like camera run out of input buffer queue so it has to wait until some buffer space is queued back from output buffer queue. The strange thing is in either circular buffer mode or live mode, it always queue back the buffer when it is buffer is not used, maybe there are other reasons so that the loop is too slow hence it cannot catch up? I assigned sufficient buffer with the (attached)


Further investigate into the issue, I measured time in the acquisition loop, in Cycle mode 'Fixed' it's about ~10ms which is reasonable for a 100fps, but in Cycle 'Continuous' mode, it is about ~100ms. Every other settings are exactly the same. However, even in 'Fixed' mode, the acquisition stops after a while(run out of input buffer queuem again). It's just so confusing to me which step actually delays the looping time? I tried using queue instead of local variables but still no luck.


The other thing I don't understand is the and (attached). I understand its outputs which are just buffer(addresses to the memory location), but why the input buffer is a digital number or char? is it because since the output is the actual buffer, so the function pass in the address to the buffer as input? 


I have attached respective files, I would appreciate any help in camera buffer management or experienced users with Andor cameras. Thank you in advance! I appreciate any of your help!


Kind regards,


0 Kudos
Message 1 of 4

I found a forum discussion that might help :


Take a look of it

0 Kudos
Message 2 of 4
Thanks for replying. It's not problem with external trigger itself I think. Since the fire output as well as arm output from camera synchronized with the triggering pulse train I used. The program seems to be functioning well. Its just the buffer that prevents it from running for more than 30 seconds live.
0 Kudos
Message 3 of 4

Hi, were you able to resolve this issue?

0 Kudos
Message 4 of 4