ControlLogix L55 and Ignorance Problem

[504bloke]

He said there is no one else available to do the job because all our staff have left.

Who's the fool then ?

 

[CountyLouthCowboys]

If there was apressure relief valve on this vessel where would I find it? Why would it not work?

 

[Ron Beaufort]

fellows, this isn't all adding up ...

 

[CountyLouthCowboys]

SO where does that leave us?

 

[Clay B.]

Maybe getting my chain yanked here

A pressure relief valve can be located almost anywhere on a vessle. The prefered location is somewhere away from people. If the valve releases then you want it to vent where it will not fry anyone. The valve should be rated to open before tank rupture pressure is reached. Tank rupture level is stamped onto any tank.

have done some thinking since my last post and have a few questions myself.

Question 1: How did this system pass inspection to begin with. All steam systems have to pass a certification before they can even be charged with steam.

Question 2: If you have a BS in mechanical engineering didn't you study valves? A pressure relief valve is one of the most basic valves used. It is a spring pushing a valve onto a seat. The pressure overcomes the sping tension and pressure is released.

 

[CountyLouthCowboys]

If the truth be known I studied Mechanical Engineering for one Year. It wasnt for me so I did a Business degree with French. I was offered this position because I knew a guy that was leaving. Under no circumstances did i ever tell lies to get the job.

Like I said I never did commissioning work on PLCs before so its going to take me some time to get up to speed. I've been office based for the past two years working on documentation.

Sorry if I seemed somewhat abusive in one of my previous mails but I take it back and I really need some help with this.

Clay there is a valve underneath the tank. I have looked at a document on the hardware involved and there is no mention of any other valve on the tank however there is level switches and a pump assiociates with it. The steam valve is not controlled with a digital output but rather an Analog what appears to be involved in some sort of closed loop arrangment.

On the PLC rack there is a number of modules, a CPU, a 1756-DNB? and I'm told all the Input/Output stuff is on whats called a Control Net.Maybe one of these modules failed?

 

[Clay B.]

Most pressure relief valves are as I described them in my previous post. Basically it is a springloaded valve. They are very obviously tagged with there rating. Most that I have delt with also have a manual release on the top of the valve so you can test the valve to make sure it has not welded to the valve seat.

The fact you say the valve is at the bottom suprises me. Most are generaly at the top of the vessle espically if it is a steam vessle. The reason for the location at the top is that the valve is for relieving pressure. Having it at the bottom means not only will you be releasing steam you will also be releasing the water that has condinsed in the tank. Generally speaking (and general is the operative word) the valve at the bottom of the tank would be to reales excess liquids from the tank. Air accumlator tanks come with valves on the bottom to allow you to drain out the water in the system.


As for the reason for your analog failure your refering to that could be any number of things. You say there are level sensors and pumps. Nether of those items are used in steam. Steam is measured in pressure and tempature. Steam is the product of water being heated. A pump is used to either compress air or move a liquid. I am not really sure of your process here. As for possible PLC problems I would need a lot more information to even guess. Ron and several others have posted where a vavle can be held on in program mode. You would need the RS Logix's 5000 software to check this. You would have to contact your local AB rep to get this software, it is not a free download. If you built this machine in house where is the copy of RSlogix's that was used to create the orginal program? I would try and find that. You also said you had someone else look at the program. That person has to have a copy of RSLogixs if they viewed the program. Your going to need a copy of the program you can post so someone can look at it.

 

[Greg Dake]

Not sure about this one...

I've been office based for the past two years working on documentation.

Sorry if I seemed somewhat abusive in one of my previous mails but I take it back and I really need some help with this.

With all due respect, you should do yourself a favor and stay in the office working on documentation and not trying to find a valve. I'm certain others here would agree based on your previous threads and posts.

 

[PeterW]

He said there is no one else available to do the job because all our staff have left.

I think there's a clue here.

If there are no staff, then he needs to get someone in on contract as an emergency. That someone would need to be a contract controls engineer, there are a lot of agencies around who will supply the correct resource.

Your boss sounds a complete arse to be honest.

It's like a house builder getting a plumber to lay bricks as the bricklayers have all left.

It's wrong of your boss to put you in this position, it is not your fault, it is obviously your boss does not have the competance to manage the task.

As everyone else has left, maybe you should ask him to turn off the lights when he leaves, honestly, doesn't sound like there's much future in that job.

Anybody higher up you can have a quiet word with, the fact that someone is injured could open your company (not you) to serious charges.

 

[Greg Dake]

There is just something highly suspect about the original post...

 

[PeterW]

lol.... I'd forgotton about that thread, I answerefd above before reaching the second page... should read all shouldn't I.

 

[Oakley]

If the truth be known I studied Mechanical Engineering for one Year. It wasnt for me so I did a Business degree with French. I was offered this position because I knew a guy that was leaving. Under no circumstances did i ever tell lies to get the job.

Like I said I never did commissioning work on PLCs before so its going to take me some time to get up to speed. I've been office based for the past two years working on documentation.

Sorry if I seemed somewhat abusive in one of my previous mails but I take it back and I really need some help with this.

Clay there is a valve underneath the tank. I have looked at a document on the hardware involved and there is no mention of any other valve on the tank however there is level switches and a pump assiociates with it. The steam valve is not controlled with a digital output but rather an Analog what appears to be involved in some sort of closed loop arrangment.

On the PLC rack there is a number of modules, a CPU, a 1756-DNB? and I'm told all the Input/Output stuff is on whats called a Control Net.Maybe one of these modules failed?

Ok, so if this IS on the up and up, then you could post a copy of the program and I am sure that many of us would be more than willing to shoot holes in it.

But on the other hand, maybe this isn't on the up and up (due to the crack reasearch and memory of Ron. Thanks Ron for recalling those threads - I don't know if Phil should cancel this thread or not. Seems like it has definitely stirred things up.

 

[JesperMP]

I, and most others that have answered to this post are the fools.

The problem is that you have to asume that anyone posting on this forums is a person who needs help.
I dont see the fun in misusing the time of wellmeaning people.
At least there is the ignore function (http://www.plctalk.com/qanda/profile.php?do=addlist&userlist=ignore&u=31918), but you cant stop him from registering under another name.

 

[Gil47]

Below your avitar when you do a post is a local time

Using that info "CountyLouthCowboys" is in the USA in the Stamford New York region



<<<<<

Maybe I am wrong as it give my local time wrong as its currently 3:29 pm here in New Zealand

 

[SLC_Integrator]

I think this is a clear cut case for the Ignore Button.