Logix chassis, hot plugging. Works but seems wrong

HJTRBO

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Join Date
Jul 2008
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Melbourne
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Hi all, so I discovered a feature I did not know on a logix platform. Hot plugging of modules. I tested it the other day on a V19 system. Installed new analog card, configured it and then started the code. All on a running system. Wow, talk about awesome. It did seem a bit odd though, thrusting a card into a live backlane and wiggling it when it didnt make positive contact, lights on the card flicking on and off! Very robust system.

Is it actually ok to hot swap? i know its supported but surely someone has a bad experience from this? Care to share?
 
I've never been able to bring myself to do it. I figure if the process is critical enough that I can't justify stopping it to swap out a card, then I certainly don't want to bring said process to a screeching halt when the hot - swap faults the cpu.

"But, boss, Rockwell SAID it was Ok to swap it hot!" :sick:

Probably just a stupid superstition from years of being taught never to do that, but there it is.
 
Removal and Insertion Under Power (RIUP) has been part of the 1756 architecture from Day 1. I've done it many hundreds of times. Being able to create a new module definition in the I/O tree at runtime is a relatively new feature; I think it was added in v16.

I've witnessed a handful of failures.

In one, a bent pin on an I/O module was shoved hard enough to short into another adjacent pin, and it faulted the backplane. We learned later that by powering up those modules in a spare chassis we could charge their capacitors so they didn't take as much inrush, and proceeded to do the rest of the plant upgrade live.

In another, an old Prosoft comms module was replaced in a very full 13-slot chassis, and the inrush current was enough to fault the backplane.

So in general: be gentle, and don't do it to completely critical or heavily loaded systems, but otherwise it's OK.

Oh, and do try to remember that just SLC-500 controllers don't support RIUP. I had a salesman pop an SLC-5/05 out of a hot chassis at Automation Fair one day... of course the chassis faulted. I took it out of his hand and pretended I had to examine it closely for the rest of the conversation he was having with the customer, so he wouldn't pop it in under power and let the smoke out.
 
As a trainer for RA, I demonstrate RIUP every course, and continue to swap ControlLogix modules in and out all day, every day, I haven't had a single "failure", of any sort, yet. I must have done it, just like Ken has, many hundreds of times.

In the backplane connector on all ControlLogix modules there is a whole row of pins that are longer than all the others, and there is a single pin (4th up, 3rd row) that is shorter than the rest. This is all part of the RIUP capability.

Please don't return the module to RA... it is deliberate !

Also, this is only true for ControlLogix 1756 family modules, nothing else supports RIUP !!
 
I was referring to the modules in the Logix chassis, not field I/O

And was Flex 5000 around 7 1/2 years ago ?
 
I have noticed with the newer style (cheaper) chassis you have to be more careful sliding the cards in. The little guide slot isn’t as good and the chassis is more flexible. I did get one stuck and damaged the pins on a card. The old ones you could slam them into the rack no problem.
 

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