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Excessive input lag on VNC - Unistream USC-B5-T24


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Hi All,

This is equal parts support request and bug / undesired behavior report. I am working on a system that has a couple of separate instruments on it - one using a custom embedded solution and one being driven off of the USC-B5. The user interface is a third dedicated, homebrew VNC viewer device that can maintain connections with the instruments and allow us to quickly switch between viewing each instrument, and send physical button presses to the instrument in question. Now, the two embedded chips communicate with each other very well over VNC - they are snappy, respond in < 50 ms with a very high frame rate, and the experience is very usable. The Unistream, however, is extremely slow to respond to any input. The screen updates quickly and works well on a display front, however, it takes about 600 ms for it to respond to any touch inputs. Once it actually recieves the touch input, it quickly processes and operates as intended, but it takes FOREVER (in PC terms, anyway) for the input to even register. This also occurs when using a PC based app as well like RealVNC or TightVNC.

Has anyone noticed this? is this a potential firmware issue or is it likely on my side?

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14 hours ago, Cara Bereck Levy said:

Does the touch on the VNC client check when Output on the PLC is active?

Hi Cara, 

Thank you for your reply. I'm afraid I don't follow your question - Which output are you referring to, and, from my understanding of the VNC protocol, I am not sure how the VNC client is supposed to check any tags within the PLC - can you give some more detail? 

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