E-stop over Ethernet

Hi All,
I thought I remember a manufacturer (or several) beginning to offer modules that allow you to send E-stop button status over a switched Ethernet network, alongside normal TCP traffic. My Google-foo is weak tonight, and I cannot for the life of me remember where I read about it.

I work in the entertainment industry, and I'm often in need of a remote e-stop or several; those positions and numbers change depending on the production. My facility is awash in CAT-5 wiring, and if I can use it, so much the better. It would make the bean counters happy too, as we'd need no infrastructure wiring changes.

What I'd love is to have a series of "remote" modules that look at an e-stop mushroom (or several), and send that status to a base unit. I'd configure that base unit to see the remotes I need, and it would provide a safety-rated relay output that interfaces with the normal e-stop system. It should also e-stop on disconnection of / damage to a cable. As a bonus, if the remote modules drew less than 30W at 24vdc, I could power them from Power-Over-Ethernet, making things a single-cable solution (external POE extractor is fine). Single cable solutions make our stagehands happy.

Key to this being successful is that the system has to be pretty flexible and easy to reconfigure. Each production has different needs, numbers of e-stops, and locations. We do rotating rep here, so the afternoon show isn't the same as the evening show, etc... Plug-and-play would be nice, and the ops shouldn't need a computer science degree to set up each show once it's configured and programmed.

I can imagine a PLC based solution with external hardware watchdog modules babysitting the PLCs and tripping an e-stop if anything decides to stop working, but that brings up all sorts of roll-your-own questions and concerns. If there's a ready-made and tested solution, so much the better. Custom designed may be what I need however, based on all of the above requirements; I imagine that any off-the-shelf system might not be so easy to reconfigure on the fly. After all, how often do you need to add and remove e-stops in a manufacturing plant?

Thoughts?


Thanks!


-rpoet

An interresting challenge.

You could use a safety PLC from Siemens with remote I/O stations fitted with safety inputs for your estop buttons. You could programme the system for say 10 remote stations over ethernet and so long as they are powered and on the network somewhere then it will function. Failure/removal of any station would trip the system.

For the system to be viable, each remote estop would have to be programmed for the same functionality. Each production would require a risk assesment that identified the safety devices required and conformity would need to be verified each time the ssytem was re-configured physically.

You also need to check that your infrastructure would support Profi-safe; you may need to replace switches. I wouldn't recommend mixing profi-safe with general IP traffic because if a timely response is not recieved from each configured station then the whole system will go int estop. A web cam being plugged in could swamp your network for example.

Nick

AB has a safety PLCs in the Control and Compact Logix line. The L43S is the one I use most often. You can use Safety Point I/O which can remote mount to an ANET card. One of the really cool features is that you can mount standard I/O on the same ANET drop.

Here is some info on the ones I tend to use.

http://ab.rockwellautomation.com/Programmable-Controllers/Compact-GuardLogix-Controllers-with-Safety

Beckhoff has Ethernet safety IO. I believe you have to use ethercat instead of Ethernet/ip.

As above mentions a whole host of suppliers nowadays provide safety PLC's which allow safety signals over communication lines.

This is achieved by the safety equipment overlaying handshaking over the network to each IO, if the network is lost the PLC and the IO react by performing pre-determined actions.

the programable safety relay range rather than the Safety PLC have progressed to E/net remote I/P points as wel as single wire types.
AB, Sick, Jocab and Pilz all have equipment in that range.
Understand this is not really plug and play as the programming for any safety system prevents easy changing. They are designed to be setup once and not moved around.
just wondering how important the safety is for the entertainment - what is it you are doing

go to www.pilz.com and download the demo software
look at the remote modules available.

Any safety system cannot be flexible in a sense that it would be easy to change its configuration via software. By definition, once the working configuration is tested and debugged, it is stored in flash memory, and it is intentionally hard to change it - just because it is safety.

So in your case you would need to design for as many E-Stop buttons as it may be needed in the future (50? 100?) and to come up with some method of hardware-plugging the unused ones. Of course this all costs money.

iant said:

just wondering how important the safety is for the entertainment - what is it you are doing

Click to expand...

Here's a partial list of effects we're doing this season:

-10' x 10' elevator that rides from the trap room to the stage, sometimes with actor(s) and scenery

-rolling "moon roof" for above to close the hole while the elevator is down

-several other smaller elevators, some with moon roofs and some without

-propane fire effect riding the elevator up to stage level while lit

-moving band platform that tracks up and down stage with musicians and instruments on top (several)

-sliding doors (think grocery store entrance doors)

-flying hats (yes, that's a thing this season)

-magic candles that disappear into the stage deck on command

It's always a good thing to be able to stop anything that's moving on stage. We're the only industry that opens holes in the floor, moves heavy things over people's heads, and suspends people from cables, all while in the dark. We make OSHA twitch sometimes


-rpoet

Look into Profinet, it is the most comparable network available which can use "standard" Ethernet routers and switches. For E-Stops or other safety related I/O use something like VersaSafe http://www.ge-ip.com/download/versasafe/13209/3668/

rpoet said:

Here's a partial list of effects we're doing this season:

-10' x 10' elevator that rides from the trap room to the stage, sometimes with actor(s) and scenery

-rolling "moon roof" for above to close the hole while the elevator is down

-several other smaller elevators, some with moon roofs and some without

-propane fire effect riding the elevator up to stage level while lit

-moving band platform that tracks up and down stage with musicians and instruments on top (several)

-sliding doors (think grocery store entrance doors)

-flying hats (yes, that's a thing this season)

-magic candles that disappear into the stage deck on command

It's always a good thing to be able to stop anything that's moving on stage. We're the only industry that opens holes in the floor, moves heavy things over people's heads, and suspends people from cables, all while in the dark. We make OSHA twitch sometimes


-rpoet

Click to expand...

This can be handled with remote E-stop circuits. The part that puckers me is the elevators. Its not just a matter of stopping them you also need them to stay where you stopped them. I am confused however. Stages are not that big, why the desire for ethernet? Why not use a hard wired system, are the elevators being moved around?

rpoet said:

...I work in the entertainment industry, and I'm often in need of a remote e-stop or several; those positions and numbers change depending on the production. My facility is awash in CAT-5 wiring, and if I can use it, so much the better. It would make the bean counters happy too, as we'd need no infrastructure wiring changes...

...What I'd love is to have a series of "remote" modules that look at an e-stop mushroom (or several), and send that status to a base unit. I'd configure that base unit to see the remotes I need, and it would provide a safety-rated relay output that interfaces with the normal e-stop system...

...Key to this being successful is that the system has to be pretty flexible and easy to reconfigure. Each production has different needs, numbers of e-stops, and locations. We do rotating rep here, so the afternoon show isn't the same as the evening show, etc... Plug-and-play would be nice, and the ops shouldn't need a computer science degree to set up each show once it's configured and programmed...

...If there's a ready-made and tested solution, so much the better...

Thoughts?

Click to expand...

Hi,

My initial thought is that you may be in the wrong Forum?

I would try looking for theater automation based companies that can provide the "ready-made and tested solution" that you are looking for. Your industry is very unique.

Having looked at your list of requirements, and while knowledgeable in safety matters, I personally would not like to be trying to design a PLC based safety system for your business.

I've highlighted key points you've made in your opening post before attempting to look for a solution for you. One company I found is www.creativeconners.com based in Rhode Island.

They specialize in theatrical scenic automation and also do remote emergency stops using a system called "Showstopper". They don't use Ethernet, but instead use 5-pin XLR plug/sockets, which as you know, are more common in theaters and the musical business. It connects to your PC using USB.

They also sell a software system called "Spikemark", which can be used to program your many different scene settings and cues. You can then call up the cues from the showstopper base unit. You can also load previous or next cue from the Showstopper.

The base unit E-Stop, or any Remote E-Stop activation stops all driven scenery for the current cue dead.

You daisy chain remotes, using XLR leads, until you reach the last remote, which is simply terminated using an XLR plug.

There is also a "Stagehand" unit which can be connected to the Showstopper. I'll let you read for yourself. Go to the bottom of the home page and under "Products", select "Control".

I don't know what regulations they conform to? You'd have to ask, but they do consultations.

I've attached a PDF of the very simple manuals for the Showstopper base unit and Showstopper remote unit.

Hope it helps.

G.

Clay B. said:

This can be handled with remote E-stop circuits. The part that puckers me is the elevators. Its not just a matter of stopping them you also need them to stay where you stopped them. I am confused however. Stages are not that big, why the desire for ethernet? Why not use a hard wired system, are the elevators being moved around?

Click to expand...

When an e-stop is struck, motor power is dropped to the servo controllers, as well as the brake circuits. This locks the elevators right where they are. Recovery is a four-step process; release the e-stop mushroom(s), reset the power distro (restores power to the servo controllers, re-enable the servo(s), continue the cue to completion (or jog manually as necessary to clear the obstruction).

Ethernet is everywhere in our theater buildings. Hard wiring would be ok if nothing ever moved, but or productions last a max of 10 months. Further, since we rep all of our shows, needs change between shows; rep means that 3-4 productions constantly rotate through each performance space. Our stagehands build and break down shows' sets twice a day.

Elevators do get moved around all the time. Many are self-contained units that drop into a hole in the deck when the show is put in. Power and control (in the form of Ethernet) gets connected and away we go.


-rpoet

Geospark said:

Hi,

My initial thought is that you may be in the wrong Forum?

I would try looking for theater automation based companies that can provide the "ready-made and tested solution" that you are looking for. Your industry is very unique.

Having looked at your list of requirements, and while knowledgeable in safety matters, I personally would not like to be trying to design a PLC based safety system for your business.

I've highlighted key points you've made in your opening post before attempting to look for a solution for you. One company I found is www.creativeconners.com based in Rhode Island.

They specialize in theatrical scenic automation and also do remote emergency stops using a system called "Showstopper". They don't use Ethernet, but instead use 5-pin XLR plug/sockets, which as you know, are more common in theaters and the musical business. It connects to your PC using USB.

They also sell a software system called "Spikemark", which can be used to program your many different scene settings and cues. You can then call up the cues from the showstopper base unit. You can also load previous or next cue from the Showstopper.

The base unit E-Stop, or any Remote E-Stop activation stops all driven scenery for the current cue dead.

You daisy chain remotes, using XLR leads, until you reach the last remote, which is simply terminated using an XLR plug.

There is also a "Stagehand" unit which can be connected to the Showstopper. I'll let you read for yourself. Go to the bottom of the home page and under "Products", select "Control".

I don't know what regulations they conform to? You'd have to ask, but they do consultations.

I've attached a PDF of the very simple manuals for the Showstopper base unit and Showstopper remote unit.

Hope it helps.

G.

Click to expand...

Thanks Geospark,

Actually, we do all our own fabrication and controls for our automation in-house, as our production schedule doesn't allow us to use outside vendors. We have our own machine shop and electronics shop, along with the more usual-for-theater metal and carpentry shops.

We use Parker DC servo systems, and write our own control software specific to what we need. Creative Conners' gear isn't up to the task of what we do. It's nice kit, but doesn't have the capabilities for our productions.

I've already designed an e-stop system using XLR cables for connection. It works great, but isn't easily expandable across multiple floors of our theater spaces due to infrastructure issues. The buildings are already wired for CAT-5, so I'm looking into leveraging it to add what we need.


-rpoet

As an example, attached is a picture of the control rack for the automation in one of our theater spaces. We have two other theaters with similar setups. All of the rack-mount enclosures were designed and built in-house.

Bottom left of the rack is the power distro. Bottom right is a 4-controller cabinet for an elevator, and all the other cabinets are single-controller units that can be used individually, or ganged as needed for multi-motor effects.


-rpoet