E-STOPs hard wire code

I know I have seen this topic covered in the past. Is there code or law on hard wiring the E-STOPs. I did a large PLC job last summer, and my boss refused, saying didn’t want to pay the extra.

Thanks for any info, I have been out of the loop 6 months with hospital stays and bed ridden ect. And some legal issue has risen while I was away

Thanks

There are Standards that describe how E-Stops should be wired/used.

Typically, there is a string of E-Stop buttons or switches that control a master-power relay. That relay should NOT affect the power-status of the PLC (especially in larger processes). It should affect the pertinent outputs... but not the PLC.

Each possible E-Stop "cause" should be wired, individually, to an input on the PLC. Then, if an E-Stop action occurs, an HMI, if one is used, can indicate exactly which E-Stop caused the stoppage. If no HMI is available, at least you can go into the program and find out which specific E-Stop device was activated.

How many times have you run around looking at all of the E-Stops trying to find the "one".... or the "two".... or...

that is basically what I did, made them run the e-stops to individual inputs, so on the touch screen it will show wich e-stop was pushed, and location of the e-stop

but all they do set the program to stop the run cycle. I wanted them also shut control power feedeing motor starters, so no matter what all would stop. that some of the e-stops were wired normally open, and others was wired normally closed. I believe that with normally open if the wire or something get loose we will not get signal to shut down the line

I believe there is code stating that the e-stops must stop the control power to the motor starters, at least stop the power feeding the outputs

So my question is this just common sense, or ae there actually codes on this.

Up until recently yes e-stops should always be hard-wired To a SAFETY RELAY that requires redundant contacts and provides error checking.

If he doesn't want to pay the extra, ask him how much his fingers and arms and legs and LIFE are worth if an e-stop system fails that is not up to snuff. Let alone trying to live with himself if anything happens to SOMEONE else because of his CHEAPNESS! I believe you could prove that an employee is costing the Co. tons more out and hurt or dead than working with a safe machine.



NO EXCEPTIONS!!!!
(except)i know. i know.

AB now has a system that uses device-net network for e-stops in the control logix family. The system is approved. I believe they are working on control net system also. It comes down to a whole new set of "messages" "safety net".
I have not used the system yet but the safety is controlled by a special proccesor. And is fully approved for use by certain sanctioning bodies.

I'm sure it not cheaper that the standard method.

Drewcrew6

Depending on the machine, you may need a category 1 to category 4 E-stop circuit.

Cat 1 is similar to the basic E-stop circuit.

Cat 4 is more complex. It uses a safety relay that has two channel monitoring of two N.C. contacts from each of the E-stop buttons. The safety relay controls two other relays(K1-K2), each one having one aux contact wired in series with the other back to the safety relay for monitoring. It's similar to a light curtain circuit.

Sorry if that's confusing.

thanks for the info, was checking on things. Since i finished the job, bailed them ot of really situation. After my last attack, and they had the job finished, I WAS NO LONGER NEEDED. Come to find out, all the extra time I put in, while I out on dissability. I was promised I would get compisated for all my time, since I was on disabilty, they coudnt pay me a regular check. Now finding out my boss covered the whole thing out, and claimed he designed the program. So right now middle of attorney and such.

SD_Scott said:

.....It uses a safety relay that has two channel monitoring of two N.C. contacts from each of the E-stop buttons. The safety relay controls two other relays(K1-K2), each one having one aux contact wired in series with the other back to the safety relay for monitoring. It's similar to a light curtain circuit.

Click to expand...

Actually, this is cat 3 and his usually satisfactory for OSHA purposes. A single fault in the safety circuit should not lead to the loss of the safety function and, where practical, should be detected.

Cat 4 shall detect a fault in the circuit and multiple faults in the circuit must not lead to the loss of the safety function.

I am going to be harsh...very harsh

I have noticed a few things.
1. Your grammar and spelling is horrendous, which means a lack of education/accreditation which puts you in a bad position regardless of ability.
2. If on disability and you worked then MORE than "your boss" should be aware of the situation, if that was the case and you were not compensated then you are in a situation you can not win in.
3. If doing electrical/control work, in the US, then you should have a copy and be familiar with NEC and NFPA code...which is legal by state or federal standards (OSHA). If not familiar...ie do not understand Category 1 to 4 etc then you should not be doing it.

NOTE: A PLC alone should NEVER control the ESTOP...study the categories to learn the proper method based on situation.

It all depends.

To whom are you being harsh?

rsdoran said:

....
NOTE: A PLC alone should NEVER control the ESTOP...study the categories to learn the proper method based on situation...

Click to expand...

A safety PLC can.

A PLC output can be used to attempt a reset on a safety relay similar to a manually operated push button. What is not acceptable is for a PLC to disable a function in a safety circuit; example would be muting.

rsdoran said:

I have noticed a few things.
1. Your grammar and spelling is horrendous, which means a lack of education/accreditation which puts you in a bad position regardless of ability.
2. If on disability and you worked then MORE than "your boss" should be aware of the situation, if that was the case and you were not compensated then you are in a situation you can not win in.

Click to expand...

Let he is without sin cast the first stone.

My grammar & spelling sux ***, but I'd bet my last bagload of $$$$$$$ the people who surround me respect me, even though I don't go off like an *** at the slightest provocation.

We also have to watch terminology..A lot of people refer to a regular stop button (That has a mushroom head on it) as an Estop..It all depends on what its controlling..From what you said about "starters" i assume motors are involved so to answer your question.."Yes" there is code preventing a normal PLC from controlling an Estop..The other thing is an Estop should never be wired Normally open..It should be fail safe..If a wire becomes disconnected that circuit shuts down..

As for working while on disability and getting paid after you are back at work is called "cheating the system!!"..Yes its done but i wouldn't want to stand up in court and admit i did it!!

Ron..I agree with what you say about most things, However i don't think a personal attack was warranted..

D

It was not a personal attack, just an observation...I am also without education/accreditation therefore have been "screwed" in numerous situations BUT I do not ALLOW people to "SEE" that disability through grammar and/or spelling....regardless of ability it can show a lacking in capability.

NOOOO a safety PLC does not...look again at what is necessary...ie it is not ALONE, note what you stated;

A PLC output can be used to attempt a reset on a safety relay similar to a manually operated push button. What is not acceptable is for a PLC to disable a function in a safety circuit; example would be muting.

Click to expand...

Personally I am not worried about sin, that is a relative term...I drink, fornicate, and on occasion smoke but rarely if ever have bad grammar or spell words wrong.

Again it was not an attack, it was too point out some issues. The main issue doing PLC/control work AND NOT BEING familiar with the code/standards involved.

ok for the one who emplied i was a dumb hick, with no education. I take offense to youur comments.
I have been a industrial electrcian for close to 20 years, and yes familiar with the code. But anyone who actualy does work out in the field have bosses that can choose wether or not to follow code. yes i know this is wrong, but reality i can follow or stand on the unemployment line
as far as my g4ammer, and spelling ect... I came down with MS a year ago, with that came problems with walking, cornation, i can only type with one hand right now....so next time instead of being rude why dont you ask first why disabled

rsdoran said:

It was not a personal attack, just an observation...I am also without education/accreditation therefore have been "screwed" in numerous situations BUT I do not ALLOW people to "SEE" that disability through grammar and/or spelling....regardless of ability it can show a lacking in capability.

NOOOO a safety PLC does not...look again at what is necessary...ie it is not ALONE, note what you stated;


Personally I am not worried about sin, that is a relative term...I drink, fornicate, and on occasion smoke but rarely if ever have bad grammar or spell words wrong.

Again it was not an attack, it was too point out some issues. The main issue doing PLC/control work AND NOT BEING familiar with the code/standards involved.

Click to expand...

The sin part wasn't about drinking, smoking, or poking.
It was about you horrific mindless sentences in you last post while chastising the original poster for his lack of grammar.

Weak, very weak.

darrenj said:

As for working while on disability and getting paid after you are back at work is called "cheating the system!!"..Yes its done but i wouldn't want to stand up in court and admit i did it!!

D

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not getting paid when i go back to work, basically they would keep my health insurance, and that be a raise, and maybe will start a plc department.

MY stupidty was believing it, against doctors wishs, instead of working 8 hours a week I pushed it, granted they did provide me a chair to sit in so all I had to do was sit there at the job site with laptop propped in my lap. then go home and spend all evning programmer, finally after going on a 12 hour day to help work out some bugs, had 3rd MS attack in 6 months, since then I been basically stuck to staying in bed, justthis week, started playing on the computer, but it is slow with use of my only working hand.
What I am upset i with my company is after doing all this work, that as soon as the job was done and i ended back in the hospital the company dropped my insurance and said if i get back to 100% come see them. Now I find my boss is claiming that he didnt know I put in any hours, that he did most of the work or had it subbed out. After talking to a lawyer alot of laws were broken, when we requested family leave act they denied this because I didnt put enough hours in to qualify. Plus not to metion the dissablty rights they vilated.

lucky I kept copy of all my programs, and any communications. plus the hours i worked.

What I was originally was looking for was exactly what the code was on E-STOPs (yes mushroom head ones) to see if any laws was violated