GPI on SC48
 

GPI on SC48

I made a box with 2 switches on it for an SC48 in a church. One button recalls the snapshot preset for their Wednesday Bible study service and the other button recalls the snapshot preset for the full band for rehearsal and Sunday service. I used the DB9 connector for the GPI contacts. But it is very annoying to find out that the only way that the switch works is open/closed. I just wanted a momentary action so if you press the button it does what it is programmed to do with one press. But because of the way the GPI contact works I have to have them double tap the switch to be sure it recalls the snapshot.

I was hoping to use this GPI for a GO and BACK buttons for theatrical use but it won’t work with the way the switches function. I will try the footswitch connectors to see if they behave the way I want. But it would really be nice if both the footswitch and the GPI on the DB9 behave or could be programmed to behave the same way. There is other functionality I want (with switches) where I don’t want to have to double tap to make it work.

Why are the GPI contacts programmed this way?

Re: GPI on SC48
 

Hi,

GP inputs are triggered by a state change, either by transitioning from open to closed, or vice versa. Same goes for the footswitch inputs, as they're essentially GP inputs with a different connector.

It's definitely possible using GPIO to have a single press of a momentary switch recall a specific snapshot, or trigger the next (or previous) snapshot. So maybe there's a simple solution here.

For example, to recall snapshot 1, create an Event as follows:

• Trigger = Input 1 (GPI Input 1), Closed
• Action = Recall Snapshot 001 <snapshot name>

Similarly, to recall snapshot two using a second switch wired to GPI 2 would be:
For example, to recall snapshot 1, you would create an Event as follows:

• Trigger = Input 2 (GPI Input 2), Closed
• Action = Recall Snapshot 002 <snapshot name>

Note that this assumes the switches are momentary, and normally open (so pushing the switch closes the contact and completes the circuit). If the switch is normally closed, simply change the triggers shown in the above examples from "closed" to "open".

It's also possible to do GO and BACK buttons for theatre this way, again requiring only a single press.

If you provide more info on how the events are set up (triggers, actions) we can work this further.

Sheldon

Re: GPI on SC48
 

I made a mistake.

I have never seen or should I say felt a switch that feels like a momentary switch actually be a push on push off switch before. I was in a rush (shows to do) to get this little box working to try and idiot proof this system for this church because I wasn’t going to be available for a few weeks to continue to hand hold their people. And it turns out I was an idiot for not testing the switch and properly reading the packaging the switch came in. I pushed the button on the switch in the store and it felt like a momentary switch.

This is a radio shack switch. I was looking for a quality switch but there aren’t any good electronic parts stores anymore. I wonder if there is a momentary automotive switch that would work and be of good quality?

Re: GPI on SC48
 

Cool, thanks for the update. Here's a trick that should work to provide single-press functionality, even with a latching (non-momentary) switch.

Basically, you set the event up with two triggers - switch opened and switch closed - so that the event fires every time the switch changes state:

• Trigger = Input 1 (GPI Input 1), Closed
• Trigger = Input 1 (GPI Input 1), Open
• Here's the trick: set the Trigger logic (top right corner of Trigger box) to "OR" - this way, the event is triggered when the switch is opened, or closed
• Action = Recall Snapshot 001 <snapshot name>

This should work, and save you having to wire another switch.

Sheldon