IamJon

What am I doing wrong with the search? I was in the AB forum and did a search for "lead lag." None of the topics that came up had lead or lag in the title, and the few I went into didn't have either word in the body of the thread. What am I doing wrong?

Thanks for all the answers guys!

Hey guys. Our specs call for AB electronic output cards (OA series) An integrator submitted on AB dry contact (OW series) Both are isolated. I haven't programmed in a while and can't remember the reason to choose one over the other. Is there a reason you would reject the dry contact in favor of the electronic (or vice versa for educational purposes). Thanks.

Right! Thanks. That should be enough to answer my question, but if anyone else has anything further, please feel free to post. ETA: Ok, so one more question on your comment - does this mean that if we are trying to build extreme reliability into the system, that we may want electronic outputs? Are the dry contact less reliable, prone to sticking?

One thing I've noticed a lot of people do...(sort of a rehash of pdl's thoughts but a little different) They get ideas on what could be wrong, but don't really pursue them all, usually for time's sake. Or they may start to look into an issue, nothing looks out of the ordinary, so they back off and look elsewhere, when the problem will be just a little deeper than they went. This usually happens when there is a group of engineers trying to solve the same problem. I've found that it is most efficient to track an issue in full as you think of them. Take a leadership role, or assign someone as the head of the group. As people think of things, if it's agreed to be a possible source of the problem, the head needs to take initiative to pursue the issue then and there. This could be made more efficient by listing a couple possibilities, addressing them in full, then going back to the drawing board if neither work. Either way's fine, depends on the scope of the problem/project which one is better.

Yes, that's a feature from AB so that the integrator can protect proprietary programs. It's something you need to work out during the contract stage of the project.

Be careful who you buy from for integral industrial PC's. We have a client who has been replacing one after the other as they keep breaking. We had a sales rep from Nematron come in and speak to us. A couple of them used to work for the above company and quit to start their own. We have another client who uses these. I tried to get a review from them through our remote office but I haven't heard anything back yet. They do have solid state drives. I would call Nematron and ask what company they broke from, and avoid that company. Sorry I can't provide any more info, it wasn't my project and I heard this from fellow employees of mine who are not in the office at this time.

How do you guys show heat tracing on a pipe in a plan view? A hatch might look like Demo work. Do you just show the pipe and put a note on it? Thanks.

I'm looking for a lighting timer that takes daylight savings into account. The lights are high mast at 480VAC. The main breaker (Feeds 2 poles) is 50A, and it is split into 2-25A branches. So far, I've found Paragon, who doesn't seem to offer a 480V timer, and AB, but they don't offer a timer/contactor package. Is my only option to purchase a timer and lighting contactor? Or is there a company who makes a 480V timer/contactor combo? Thanks.

I think what I'm going to do is just get a basic astrological timer coupled with a standard 480V contactor, and have the timer relay activate the contactor. That should do it.

From what I've heard, Toshiba really shines in medium voltage applications.

Thanks Paul!

I searched AB's and Belden's websites for info on RS-232 and DF-1 communications. I have a Raco Gateway autodialer that will communicate over DF-1 to a CLX, but I can't find specs for a cable. The only thing I've found is a reference to part numbers on the Belden FAQ page. I thought AB had cables listed on their website? Please point me in the right direction to get info on RS-232 cables. At least a part number and simple description. Thanks.

Wow, get the myrrh and unwrap the burial shroud, cause this thread has been resurrected! Didn't realize it was so old :)

Hey guys, long time. I think maybe you're reading too much into my question, or looking at job-specific info. This is just a general question... in general, is there a reason to choose an RK5 for a 0-30A application. I guess my main question was, was it a typo in our spec to list an RK5 for 0-30A? Is there any application where you'd want to use an RK5 over a CC for a 0-30A application, or would a CC always be sufficient?

It's nice to come to a place where everyone else is a nerd too (cue Cheers music)

Redundant is always used in glass furnaces. If one, TC goes down, you might not be able to control a forehearth very well, but your furnace won't go down, freezing the glass and costing millions upon millions of dollars to replace the furnace. Plus there are multiple forehearths that can still make product. That said, here's an interesting story. I was doing a job at a glass plant where I was making changes (live) to a redundant system which utilized indirect addressing for most of it's code. Once I got the changes in one processor, we decided to switch processors to make the changes in the other. Well, every time we switched, the processor faulted. As it turned out, there is a timer in the old BCM (backup control module i believe) that times the delay to switch processors and start running code. The time delay was set well below... I think maybe it was below scan time... but at any rate, it was set way to fast. This would rush the switch and fault the processor. Moral of the story (which has already been discussed in this thread), the PLC was more reliable than the redundancy itself, due to the redundant system's complexity. That said #2: Rockwells redundancy has come a long way from the BCM and is much easier and more reliable.

I'm looking for a propane generator around the 60KW range. The only company I can find that makes one is Kohler. Anyone know of any other options? I'm located in the MI, IN, OH tri-state area. Thanks. Edit: CAT and Generac also make them. I guess they're a new offering from CAT.

They get more power out of the same motor by adding a larger alternator. Most companies now have sizing software, so that takes a lot of the design burden off the engineer. I sized this one with Kohler's online software. Some people still prefer soft starts over VFD's because they see a benefit of reliability in the hardware, if there is no reason to do speed control. Then again, we've had clients add VFD's then add soft starts on a VFD bypass. In water utility, they're a bit slow getting into technology, and reliability being of utmost importance, they get nervous adding a computer in the mix that they can' just have their maintenance replace quickly.

Are you using indirect addressing? It seems to me that maybe you're going about your addressing structure wrong. You need separate tags for each of the 32 tasks, but only one ladder routine that all of your tags will get fed through. Indirect addressing uses the JSR (jump to subroutine). You put your data into the JSR and use that to jump to your subroutine that you'll use for the 32 tasks. I don't have my thumb drive on me today. I'll bring it in tomorrow and I can explain in a bit more detail. It has a couple examples. Also, what platform are you on? RS5000, 500? Seimens? I really only know Rockwell, and my answer will reflect that.

Here's an archived thread about IA: http://forums.mrplc.com/index.php?showtopi...aded&start= If it shows up with only 1 post, on the top right click 'options' and select 'standard' under 'display mode' OR: Why not just create a new array for the data that is going to the HMI for all 32. Then, when the routine is complete, move that data to the HMI tags. You can set a register or counter that will keep track of which of the 32 tasks you're on and copy the data into the appropriate HMI tags based on what the value in the register/counter is.

Thanks for the tips guys. It's going to be propane because at the location, that is the most readily available fuel, and they want an on-site tank. It's backup power for a utility, so it will definitely be industrial grade.

I've used Precision Digital. They make some Nema 4x meters that go down to -40 deg C.

That's no way to respect the ladies ;) I may have edited your quote...

Yes. But I was only talking about physical death. I believe our choices mostly affect when we die. Saying God determines when someone dies opens the door to being angry at God for a loved one's death. Just as you can't blame God for war and famine. This world is fallen and most suffering is due to our own choices, not God's will.