E Stop Installation

Could I get some comments on how to install a E-stop.
I'm totally new at this and I was looking for some
direction on the typical install and theory. I would appreciate your help.

Thanks-

K-

At risk of sounding like a smart arse, you should get hold of the standards relevant to the area your installation is going to be, because it's your neck if you take on safety task you don't understand. The Pilz website has good beginner information on it as well, so check that out.

I agree with Binaural, find rules and regs. READ OSHA.
Many makers of safety equipment have great tools on their web sites.
Study "Risk Assesment"

Here is another link from Omron/STI
http://www.sti.com/safety/index.htm

For more direct helps from the forumn members you may consider a decription of what you are trying to do, how the equipment operates, etc.

Hope this helps

In addition to the other information, I thought I would give my opinion.

Don't let anyone talk you into just using relays or a standard PLC for the system.

Do a risk assessment and don't do it by yourself. You should involve a safety person, maintenance person, and production person to guide you through tasks that they do.

Use good documentation for the system.

Be wary of safety items that use special programming unless all the maintenance people understand how to use them.

Put in good "diagnostics". I use a banner EZLight at every e-stop (green OK - flashing red tripped). I bring a mimicked input into the local plc for display on an HMI. I also have a map displayed on the HMI of the system showing the location and status of each e-stop.

Check your system out after the installation to make sure it works as designed (yes pull every e-stop and document what happens). Also help them develop a way to check every e-stop on a periodic basis.

On systems with inertial energy, make sure that the system is at zero potential before allowing a gate to be opened.

Keep in mind that on some systems, an improperly designed e-stop can cause more problems. Think of a person trapped by a moving system. As part of your risk assesment, you need to take that into consideration also.


The best advice is the same as the previous posters. Read the literature out there and learn all you can before you attempt this design.

As the others have said, PLEASE READ REGULATIONS on safety. Each application will call for differant amounts of safety. You need to ask yourself, "What do I want my safety's to disable?". Do you need to stop all operations? Or just specific ones? Your design could be as simple as killing control power to your I/O or as complex as sending a fault bit and having logic to check it's operation. Use your imagination but please do it all within regulation. There are too many unsafe engineers out there.

Thank you All for your input.
It is very helpful and appreciated.
I will consider your advise
and move on from there.
Also, thanks for suggesting
the Web-sites that were recommended. (I'll check'em out)

K-

I would add perhaps look at a similar system to the one you want to add to. How is that achieved?

Also, consider what energy sources you want to "Emergency stop". It could be that you also need to dump air pressure, on a machine with pneumatic cylinders but wouldn't want to do this if you had valves controlling liquids!!!

To help maintenance down the road, make sure all of the connection are easily accessible and are sturdy joints.

Nothing worse then having to open up every wire way in the machine looking for a loose amp plug that was buried in the wiring.

Also consider e-stop buttons that look dramatically different when pushed. Example: they stand up high, but when pressed go down flat. Or use lighted units.

Many maintenance calls have been solved by pulling out an e-stop that didn't get noticed because it looks almost the same when it is pressed as it did when it was out.

TheStarr said:

e-stop buttons that look dramatically different when pushed. Example: they stand up high, but when pressed go down flat. Or use lighted units.
.

Click to expand...

Many places I've seen use both feedback to the PLC and a lamp integrated into the button. Personally, I loathe, hate and despise hardware designers who make me delve into a cabinet to find out which blasted E-Stop has been pressed.

First you need to assess the level of risk. this will impact what type of e-stop you need.
A simple contact opening a fail to safe contactor or a dual contact cross monitored type
this will help the risk assessment
http://www.machinesafety.co.uk/content/view/91/188/

http://www.automation.siemens.com/fea/html_76/down_module.htm

this site also has some good manuals on E stop circuitry as well as a good explanation on various regulations and risk assessment

What are you intalling the E-stop on? One piece of equipment or a motor control center that will need to stop everything associated with it?
Just wondering.

I agree with brucechase description, also on a more serious note dont kill plc inputs kill power to the outputs ie safety relay monitors stop buttons power to outputs goes through safety relay. should be 3 contact blocks on e stop 2 n/c for e stop cct and one normaly open which you can use in a program to tell which e stop is pressed.

Try www.jokabsafety.com some great info here and a safety book you can download

This

At the risk of getting flamed I have to ask... Just what the heck are you doing asking how to configure an E-Stop on an Internet forum?

Clearly you are NOT an Elecrical Tradesman or Engineer and should NOT be playing around with things that you know NOTHING about. That is how people get killed.

My suggestion: Hire a professional or risk finding out what the inside of a Coronor's Court looks like.

Bah Humbug,
Muz