I_Automation
Lifetime Supporting Member
Not a PLC. but years back I had a smart VCR that after a power failure would remember the channel scan settings, the nicknames for each channel, date & time and if something was programmed to record over the next 14 days.
The problem was if the power glitched for a half second it was a total wipe. If a gust of wind went by our house the power would cut off momentarily about 45 seconds later, so I figured a wire was broken internally about 1/2 mile northeast of us.
I ended up putting the power through a 30 second timer, if there was a glitch the VCR would be off 30 seconds.
I also program in similar timers when a PLC is controlling the power to a VFD or servo controller.
The problem was if the power glitched for a half second it was a total wipe. If a gust of wind went by our house the power would cut off momentarily about 45 seconds later, so I figured a wire was broken internally about 1/2 mile northeast of us.
I ended up putting the power through a 30 second timer, if there was a glitch the VCR would be off 30 seconds.
I also program in similar timers when a PLC is controlling the power to a VFD or servo controller.