Access to the PLC

We are having issues with are safety manager in regards to opening panels when accessing the plc’s (Siemens MPI connector). This is a violation in regards to the arc flash requirements. Is there a panel interface that can be mounted on the exterior of the panel and connected directly to the MPI interface of the Siemens PLC S7-300 and 400 series on the inside of the panel?
Thanks
rmonoe

Try a Graceport.

This should do:

http://www.automationdirect.com/adc...nication_Ports_(DB9,_RJ45_only)/ZP-PNA-06-100


-rpoet

You could get mount something like this on the door or side of the panel and leave the MPI in the panel. I'm not familiar with Siemens plcs, but you can google 'panel mount usb' or whatever connector type you need and you'll probably find something that will work.

I'm using an ethernet one to connect through a switch to some vision sensors.

randy said:

....This is a violation in regards to the arc flash requirements.....

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Err...ah...yeah..arch flash

I would challenge that.

First, I understand arc flash and required safety items and agree there is a reason for it. HOWEVER...it's such a hard topic to fully digest I doubt your safety manager knows all the details. Has your plant gone through a hazard analysis and labeled each panel with the arc flash hazard ratings and PPE levels?

Most situations will be category 0, which is minimal PPE which should be issued. Then opening panels is really not a big concern when you talk about arc flash. Don't get me wrong, if the PLC is in a 480 VAC MCC with alot of power then it's not a good idea to go in there at all!

But, if you're talking 120VAC control panels....ugh.

Anyway, there are products as others have mentioned, the arc flash topic really is irritating.

Voltage in the panel? If it's under 2xx volts (can't remember if it's 208 or 240), then regarding arc flash, no matter what the calculations indicate, it's category 0. Under 2xx volts, there simply isn't enough energy available to maintain an arc.

OZEE said:

Voltage in the panel? If it's under 2xx volts (can't remember if it's 208 or 240), then regarding arc flash, no matter what the calculations indicate, it's category 0. Under 2xx volts, there simply isn't enough energy available to maintain an arc.

Click to expand...

If there reference in NFPA 70E that states this? Or is this just your experience?

IEEE 1584 states, “Equipment below 240 V need not
be considered unless it involves at least one 125 kVA
or larger low-impedance transformer in its immediate
power supply.”

http://www.newark.com/pdfs/techarticles/littelfuse/ArcFlashHazard.pdf

You can use the NFPA tables, but nearly everyone uses the IEEE 1584 method to do their calculations.

If it's under 2xx volts (can't remember if it's 208 or 240), then regarding arc flash, no matter what the calculations indicate, it's category 0.

Click to expand...

It appears that the NFPA tables indicate that for 240 volts and working on Panelboards and Other Equipment, there are 4 work tasks that fall under Risk Category 1 (and 4 others that are Category 0). The look-up pivot tables in this spreadsheet will help to summarize the NFPA tables.

what is the environment we are talking about.
I work in an environment where Mobile Phones are banned.
even in their switchroom. All the control panels are there.
I suppose a phone gives a bigger spark than a 50Kw motor contactor/VFD setup
Also
Does you company or national regulations have restrictions on panel access. - over here you need to be a Qualified Electrician to work on LV
(50 ~ 1000 V ac) so access is legally limited.