# Kenwood radio causes PLC to crash!



## eric7379 (Jan 5, 2010)

Just an "FYI" in case anyone uses radios at work.


At work, we use Kenwood TK-3160 radios for communication in the plant. My coworker was standing in front of a Siemens S5 rack for one of the printing presses and as soon as he keyed up on his radio, BOOM! All of the fault lights on the S5 rack lit up like a Christmas tree and the press came to a screeching halt. Oops!! When the press shut down, it ended up smashing 2 blankets and paper went in the rollers of 2 units. Three hours later, they tried starting back up only to have to shut back down because they had to change one roller and re-set all of the other rollers. All in all, about 6 hours of downtime total. Management was not at all pleased. Oh well! Not the fist time, won't be the last time!

We know that it was the radio that cause the rack fault because after we reset the PLC (the press was already down), my coworker (as a test) keyed up on his radio in front of the rack like he did before and, sure enough, the rack faulted out.


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## McClary’s Electrical (Feb 21, 2009)

eric7379 said:


> Just an "FYI" in case anyone uses radios at work.
> 
> 
> At work, we use Kenwood TK-3160 radios for communication in the plant. My coworker was standing in front of a Siemens S5 rack for one of the printing presses and as soon as he keyed up on his radio, BOOM! All of the fault lights on the S5 rack lit up like a Christmas tree and the press came to a screeching halt. Oops!! When the press shut down, it ended up smashing 2 blankets and paper went in the rollers of 2 units. Three hours later, they tried starting back up only to have to shut back down because they had to change one roller and re-set all of the other rollers. All in all, about 6 hours of downtime total. Management was not at all pleased. Oh well! Not the fist time, won't be the last time!
> ...


 


I wold have that radio tested. My guess is, it is off frequency or bad filtering.


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## drsparky (Nov 13, 2008)

It happens. 
You could look at the entire system. What frequency? Grounding, bonding, shielding done correctly? High powered or low powered TK-3160? Is the PLC in a cabinet? Maybe look into adding ferrite beads. Easy solution "Do NOT KEY RADIO NEAR PLCs" signage.


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## JohnR (Apr 12, 2010)

Can we get a big thank you for the FCC.

They have this stupid idea that all electronic items should accept outside interference. Yes they put in there that the item should not create interference, but you should be able to build something that does not accept any.



> This device complies with part 15 of the FCC rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) *this device must accept any interference received, including interference that may cause undesired operation.*


You might want to check for this on the plc, literature just in case of liability for the down time costs.


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## MDShunk (Jan 7, 2007)

eric7379 said:


> ... My coworker was standing in front of a Siemens S5 rack for one of the printing presses and as soon as he keyed up on his radio, BOOM! All of the fault lights on the S5 rack lit up like a Christmas tree and the press came to a screeching halt.


Easy solution... don't do that. 

I remember the first time I keyed up a radio in front of a panel full of GFCI breakers. Sounded like Chinese New Year.


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## Bob Badger (Apr 19, 2009)

I was trouble shooting an EMS and when I keyed my radio all the LEDs went from flashing to solid and all the outputs went 'high'.

I stopped doing that. :laughing:


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## MDShunk (Jan 7, 2007)

JohnR said:


> Yes they put in there that the item should not create interference, but you should be able to build something that does not accept any.


I think they surely could, but get ready for sticker shock. I'm not sure you'd want to pay for it. That would make everything sort of a MIL spec item. That would take your $5,000 PLC and turn it into a $50,000 PLC.


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## Jlarson (Jun 28, 2009)

This is why we don't use radios at all. :no:


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## Electric_Light (Apr 6, 2010)

If you fire a GMRS radio next to a CFL, it will cause it to change brightness or sometimes shut down completely. I also have a desk clock that will beep its alarm and reboots every time my fires GSM signals.


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## drsparky (Nov 13, 2008)

MDShunk said:


> Easy solution... don't do that.
> 
> I remember the first time I keyed up a radio in front of a panel full of GFCI breakers. Sounded like Chinese New Year.


I have seen that too.:thumbsup:


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## tommu56 (Nov 19, 2010)

Make sure all the connections are good 

We are in the process of replacing of our S5's to S7-400 in our roll stands because we had a problem with years of intermittent QVZ faults and no one could figure it out during the replacement trouble shooting the 400 we found the problem wire an analog input 0v was not connected properly on one of the terminal strips and was completing the circuit through the backplane .

tom


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## frenchelectrican (Mar 15, 2007)

MDShunk said:


> Easy solution... don't do that.
> 
> I remember the first time I keyed up a radio in front of a panel full of GFCI breakers. Sounded like Chinese New Year.


 
It did happend to me as well manged to trip out the main RCD for one manufactering plant and by the way that is a 3200 Amp service { 415Y240 volt service } when myself and other guy keyed the radio the same time Kapow heard quite few breakers kick out.

After that never again!

Merci.
Marc


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## Big John (May 23, 2010)

We've had similar problems with our GE Versamax PLCs: Even keying a cheap walkie-talkie while standing in front of them will cause all the analog I/O's to go nuts. It's almost worse than having it trip, because instead you get a lot of unpredictable machine function.  No thanks.

-John


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## eric7379 (Jan 5, 2010)

tommu56 said:


> Make sure all the connections are good
> 
> We are in the process of replacing of our S5's to S7-400 in our roll stands because we had a problem with years of intermittent QVZ faults and no one could figure it out during the replacement trouble shooting the 400 we found the problem wire an analog input 0v was not connected properly on one of the terminal strips and was completing the circuit through the backplane .
> 
> tom


 
MEG roll stands, by any chance??


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## Jlarson (Jun 28, 2009)

Jlarson said:


> This is why we don't use radios at all. :no:


I phrased that poorly, I meant we don't use radios in control or electric rooms where keying up might cause issues. So pretty much we operate under the don't do that anymore system.


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## miller_elex (Jan 25, 2008)

That's why there should be wall phone conviniently placed around the plant. You know, with the handset cord that stretches out thirty feet.


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## eric7379 (Jan 5, 2010)

Jlarson said:


> I phrased that poorly, I meant we don't use radios in control or electric rooms where keying up might cause issues. So pretty much we operate under the don't do that anymore system.


This is the stance that we have taken since this initially happened. We also made signs to warn people to not use their radios in certain areas.



miller_elex said:


> That's why there should be wall phone conviniently placed around the plant. You know, with the handset cord that stretches out thirty feet.


We do have phones placed around the plant. A lot of times a radio is much more convenient. Especially if we are working outside or on the roof. A phone is nice, but a radio is better, IMHO.


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## Jlarson (Jun 28, 2009)

miller_elex said:


> That's why there should be wall phone conviniently placed around the plant. You know, with the handset cord that stretches out thirty feet.


Dude... cell phones :laughing:


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## eric7379 (Jan 5, 2010)

Jlarson said:


> Dude... cell phones :laughing:


 
:laughing::laughing:


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## BBQ (Nov 16, 2010)

Jlarson said:


> Dude... cell phones :laughing:


Dude... cell phones are radios.:laughing:


Or does your cell phone plug in?


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## Jlarson (Jun 28, 2009)

BBQ said:


> Dude... cell phones are radios.


Dude... I know, I'm just giving miller a hard time. :laughing:


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## DanS (Oct 30, 2010)

*I've seen this happen before.*

Probably a shielding issue. Check to see if the cabinet that houses the PLC is properly bonded. Also make sure that shield wires are grounded in the cabinet only in order to prevent ground loops.


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## miller_elex (Jan 25, 2008)

Jlarson said:


> Dude... I know, I'm just giving miller a hard time. :laughing:


Not exactly, a motorola MOMS radio is what, how many megahertz, 250Mhz? 480, google that one up.

A celphone is now 2.5Ghz? I think celphones are now frequency hoppers too.

There is a big difference between the two when it comes to radio frequency interference.


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## miller_elex (Jan 25, 2008)

DanS said:


> Also make sure that shield wires are grounded in the cabinet only in order to prevent ground loops.


Ground loops will fuh-huck your world. One more reason to avoid shielded wire and bozo installers.


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