Estop Wiring

[norty303]

I will still need to run another cat5 to the stage box for the interlock portion.

Yep, nothing changes there.

I would really like to see this relay and how you plan to wire it up.

I will show you then, when i've done it

So you are splitting off the USB extender power supply to this relay and running contact wires to your estop button.

Basically, the 5v supply is connected to the coil of the relay (via some resistors/transistors for drive/current control). The relay is NO on all contacts, so 'safe' with power off.

The loop to the estop is in series with the 5v supply, so you hit the estop, you break the supply, and all relay contacts go open. The relay contacts connect to 4/17 for each projector. The projectors provide the 5v supply for their own safety loop, so you just need the relay to complete the circuit.

Using this setup you can repeat ad infinitum. Each 'device' generates a 5v loop 'backwards' to its control device, which simply needs to be completed somehow.
So working backwards from the end projector, you could have:

Projector <-- Projector <-- Projector <-- Stagebox <-- estop

Do you think long travel distances would effect the performance / reliability of the USB extender?

The USB extender is rated for up to 100m so it should be good for at least that.
The USB extender has NOTHING to do with the estop functionality, other than i tap off 5v from the PSU (which is purely for convenience as it sits at the same location. It could be any other 5v supply)

Equally, the cat5 used for the estop could be any other piece of 2 core cable. I just choose to use cat5 because its already on the loom and its cheap.

If pins 4 and 17 are used to detect if a DAC is present, and pull them out of the loop, how will the laser operate since i've broken that loop now?

You will have to test. I suspect the projector uses the interlock loop to see if a DAC is present in order to decide whether to switch on standalone mode, and the DB9 to determine if it's safe to display when under any control (DAC, standalone, DMX, etc).
If you have no interest in using the standalone mode then you could just tie 4/17 inside the projector so it thinks it's always connected to a DAC (again, you'll need to check how its actually wired)
The DB9 will ultimately control if you get any output. If it thinks it's always connected to a DAC, you won't get any output unless it IS connected to a DAC.

[JD3]

Attachment 44335

quick little relay circuit I made up. interlock wires will connect to the N/O pins of the Relays. RJ45 connector to carry the loop to the estop button.

look like that will work?

[norty303]

I can't really see it properly on my phone but that's the sort of idea. Note, you can get 4PST NO relays to simply things

[JD3]

Yea the software was kinda limited in what components I could use. Just grabbed a random relay out of the list.

[norty303]

Here's my board all finished and fitted. Thanks to DZ for finishing off my circuit diagram for me!

2x 100R resistors, 1x 100K resistor, 1x 2N2222 transistor, 2x diodes and 2x 4PST relays, and an evening burning my fingers on the iron!

I'm going to get some boards made up if I can find a footprint file for the relay. they were about £12 each which is still cheaper than 4x SPST. I wanted to use the relay sockets, to make switching them out easier in the event of a failure, but they were out of stock at the time.