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Keeping GPIO output on for a long period

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Adam Liebreich-Johnsen
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I have a setup of four LS424s playing in sync as a lobby display in my office. They have no issues playing in sync. A while back we decided to simply powering the display on and off, so I got a GPIO controlled relay to power on the monitors and built the presentation so that it starts up on a blank event handler screen. I have a timeout set up so it goes to a superstate wherein is the videos that play in a loop. Every morning at 9:30 it goes to this superstate and sends GPIO on through output zero. It's supposed to stay on until 6:15PM(18:15 in the presentation), but it usually turns itself off far too early and I have to manaully send a UDP command to turn it back on.

 

Is there an issue keeping the GPIO current going for that long? What can I do to mitigate this issue? Unfortunately the relay is only programmable to turn on when it receives voltage through GPIO. I am using this power strip to control the monitors.

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    Bright Scripters

    This relay has outlet with reverse logic.
    You could try it and see if you get better result.

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    Adam Liebreich-Johnsen

    That's my current workaround. I was mainly wondering for future uses of GPIO. The test case in our lobby is just a demo for potential clients, but I was thinking about possible future deployments.

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    Stefan Reck

    Have you measured the actual control current draw of the power strip and checked whether or not its input is optically isolated? 

    To my knowledge the GPO ports on a BSP are current limited to driving a maximum of two standard LEDs in parallel and they are *not* optically isolated. This kind of control system is very susceptible to ground loops. In my experience doing anything other than going straight into an optocoupler or SSR with it is asking for trouble. 

    As an alternative you might look into a NETIO device. https://www.netio-products.com/en

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    Adam Liebreich-Johnsen

    So I arrived to the office late today after reversing the logic of the on/off command and plugging the monitors into the "Normally On" outlet, and I found that the lead player in the cluster had recently rebooted. According to the DWS it happened about 20 minutes before I arrived. So my question is, would it make sense to have a blank presentation that plays when the monitors are supposed to be off, and then a presentation with the videos playing, so if the player does crash and reboot it goes back to playing instead of blank?

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    Adam Liebreich-Johnsen

    >Have you measured the actual control current draw of the power strip and checked whether or not its input is optically isolated? 

    I'm not sure what you mean by optically isolated, but as far as I know the power strip's relay takes anything from 3 to 24v to trigger.

    >To my knowledge the GPO ports on a BSP are current limited to driving a maximum of two standard LEDs in parallel and they are *not* optically isolated. This kind of control system is very susceptible to ground loops. In my experience doing anything other than going straight into an optocoupler or SSR with it is asking for trouble.

    What is an optocoupler or SSR? Apologies, I'm not an electrician.

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    Stefan Reck

    https://en.wikipedia.org/wiki/Solid-state_relay

    https://en.wikipedia.org/wiki/Opto-isolator

    The basic premise is: avoid connecting the ground pin of the GPIO barrier strip to "foreign" ground paths. Microcontrollers like the BSP tend to get really annoyed if they have to carry stray currents between different ground potentials. GPO should only be used to drive LEDs (Optocouplers, SSR´s...), or maybe the GPI of another BSP nearby that is powered by the same circuit and fed by the same network switch.  

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    Adam Liebreich-Johnsen

    Okay, so I have determined that the BrightSign player itself is crashing and that's why the power relay is powered off. I bypassed that issue temporarily by just using two presentations, scheduled to be the "on" presentation when it's supposed to be on and the "off" when it's not. So if the player crashes, it will go back to the loop it's supposed to be playing. My issue now is, why is the player crashing?

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    Bright Scripters

    You could share the presentation here so we can take a look.
    Is it randomly crashing? Is there any pattern?
    Is the player on BSN? Is the player connected to a network at all?

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    Adam Liebreich-Johnsen

    Is there an option to upload files here? It says I can only upload images.

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