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I have a customer with some equipment controlled by a V1210 PLC with a bunch of I/O attached. This equipment is in the middle of nowhere and the 110V power is a bit iffy. There seems to be frequent voltage spikes or other glitches that often cause the PLC to lock up (power cycling brings it back with no problem). They have a UPS, which does keep things powered up, but doesn't seem to block other kinds of glitches. Anyone have a recommendation for high quality power conditioning for 110V?

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Hi Flex, I think that before anything else is suggested, we need to know how  the power gets to the site.  There are so many variations in how a power company might run a line to the "middle of nowhere", and they all might have an influence on the issue and it's resolution.  Ask some questions!

cheers, Aus

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You will need to analyze the PLC's wiring diagram and, if possible, divide it to identify the cause of the problem.

For this I use a battery connection and try to operate the control without a power supply.

If this does not help to identify the cause, I try to isolate all the circuits using isolating devices (relay, optocoupler isolator).
Usually the cause is interference that can be removed with the help of ferrite rings on wires,  RC links for AC  and  diodes for DC on inductances that were forgotten during installation.

In my opinion, the problem is not the power.
  It is noise from some device in ON-OFF-ON condition.

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Shameless self-promotion - we sell products from these guys:


I took this line on after a customer blew up the com port on a V230 that had a remote Weintek HMI displaying a few variables.  The HMI was in a guard shack and a bad lightning storm rolled through.  I can only guess the data line became an antenna.

They have products for incoming power line surge protection as well as products to put on your data lines.  Take a look at the Technical Papers link.

Joe T.

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Based upon how I read your situation, surge suppression alone won't solve your issue.  Instead, look at the SolaHD MCR power conditioners and voltage regulators from Emerson.  Surge protection will not smooth out the dips and swells created by inconsistent power quality.  (Disclosure:  I have no personal or financial interests in the product.)

Additionally, each transient event will accumulate damage to the MOVs in surge suppression devices eventually causing them to fail.  Power quality is more than just surge suppression.

Additionally, verify that the local grounding is done correctly.

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