Let us not forget what an EMERGENCY STOP system is SUPPOSED to be designed for, and forget about what you ACTUALLY use them for.
Worst thing to ever happen!!
- Thread starter dbh6
- Start date
Let us not forget what an EMERGENCY STOP system is SUPPOSED to be designed for, and forget about what you ACTUALLY use them for.
You should have a plain old STOP button for that, backed up with a locked-out disconnect switch. If your machines are stand-alone units, then you can safely have individual Emergency Stop buttons for each machine. In most assembly lines, that is not the case.
One thing that really ticks me off is when operators use the Emergency Stop as a Machine stop. Interlocking them all like that cures that problem in a hurry I bet!
Clay B.
Lifetime Supporting Member
What not to do with a VFD
Was working with an engineering firm several, several years back. They where installing a really long roller conveyor. Each motor on the roller conveyor had a VFD. The VFDs where mounted in a small enclosure with a thru the door disconnect. The electrical guys wired up the power to each panel along with some control wires going directly to the VFDs. My job was to program the PLC to start the roller conveyors in sequence and give them a speed reference.
Well we started the line staggering the start of each motor. Each VFD exploded in the exact order we started them. It turned out the guys who built the VFD panels had crossed the power in and motor out on the VFDs.
Was working with an engineering firm several, several years back. They where installing a really long roller conveyor. Each motor on the roller conveyor had a VFD. The VFDs where mounted in a small enclosure with a thru the door disconnect. The electrical guys wired up the power to each panel along with some control wires going directly to the VFDs. My job was to program the PLC to start the roller conveyors in sequence and give them a speed reference.
Well we started the line staggering the start of each motor. Each VFD exploded in the exact order we started them. It turned out the guys who built the VFD panels had crossed the power in and motor out on the VFDs.
gbradley
Lifetime Supporting Member
About a year ago, I asked the electrician to give me 240V three phase to connect a Kinetix 300 for some testing.
I said, "Is that 240V?"
"Yep, it’s all ready."
I throw the switch, there was a bright flash, a pop and the lights went out.
Turns out that the line was 480V.
All breaker boxes and disconnects are clearly labeled now.
And he verifies voltage with his meter for sure.
I've done dumber things when I was younger, but that was probably the most expensive one.
I said, "Is that 240V?"
"Yep, it’s all ready."
I throw the switch, there was a bright flash, a pop and the lights went out.
Turns out that the line was 480V.
All breaker boxes and disconnects are clearly labeled now.
And he verifies voltage with his meter for sure.
I've done dumber things when I was younger, but that was probably the most expensive one.
keitho
Member
Not directly PLC related...
But I was sent to Holland to work on a PLC so there is some tie-in.
My less-than-brilliant moment actually started when I was packing for the trip. I hadn't traveled internationally in a couple of years, but I remembered I had to pack my power adapters for all the electronics I carry. I thought - heck, I can pack this cheapie power strip, plug it into one adapter and then just plug my goodies into the 'normal' US outlets. Brilliant!
Until I actually tried it and realized the plug strip contained a surge suppressor. Cue: immediate loud pop with ceremonial release of Magic Smoke.
Still think it was a good idea; just poor implementation.
But I was sent to Holland to work on a PLC so there is some tie-in.
My less-than-brilliant moment actually started when I was packing for the trip. I hadn't traveled internationally in a couple of years, but I remembered I had to pack my power adapters for all the electronics I carry. I thought - heck, I can pack this cheapie power strip, plug it into one adapter and then just plug my goodies into the 'normal' US outlets. Brilliant!
Until I actually tried it and realized the plug strip contained a surge suppressor. Cue: immediate loud pop with ceremonial release of Magic Smoke.
Still think it was a good idea; just poor implementation.
rpoet
Member
But I was sent to Holland to work on a PLC so there is some tie-in.
My less-than-brilliant moment actually started when I was packing for the trip. I hadn't traveled internationally in a couple of years, but I remembered I had to pack my power adapters for all the electronics I carry. I thought - heck, I can pack this cheapie power strip, plug it into one adapter and then just plug my goodies into the 'normal' US outlets. Brilliant!
Until I actually tried it and realized the plug strip contained a surge suppressor. Cue: immediate loud pop with ceremonial release of Magic Smoke.
Still think it was a good idea; just poor implementation.
Actually, when I worked on cruise ships, the audio guys would do that on purpose. Procurement could never get ordering right, and always bought surge-suppressed power strips even though we told them not to. The MOVs don't like the wonky floating delta power on ships, and they tended to go POP! The audio tech would intentionally blow the MOVs, and then the power strips would work just fine
The strips they bought were plastic-welded together, so we couldn't even open them to remove the MOVs the right way.-rpoet
Mr.Vonny
Member
just recently understood.... around 7 and a half yrs ago, on dec-5-2005, i've got involved in this (industrial automation) business ... that's really a biggest fail in my life))
Not a disaster, just a lot of wool-pulling.
I once had a job with a small company building "bespoke" machines. I soon came to realize that bespoke translated as "the ones that nobody else wants to take on".
We made a machine for wrapping bouquets of flowers and the customer wanted an on-site demonstration. Development had dragged on and they were getting a bit twitchy having put a fair amount of money into it. The machine was just large enough to walk around inside with a little headroom. It pulled in plastic film from a roll via an accumulator, fed it past a blade and presented the cut length to a table above head height. There was a vacuum belt and any number of extending suckers to handle its journey. The table could rotate to preset angles and was driven three feet along a track (while hot glue was sprayed along one edge of the film), to where one of four cones mounted in cross-formation swung round to collect it by rotating and wrapping the film around its surface (with a little help from air jets, brushes and foam rollers).
The four cones indexed round and a cylinder inside each one extended at the appropriate moment to send it downwards into the waiting embrace of an assembly of vacuum suckers mounted on several articulated arms. (loads more tiny cylinders to flex the joints of the arms, which were more like giant fingers). Four of these groups of arms and suckers were mounted on an indexed carousel so that when the extended cone had deposited the wrap and withdrawn, the carousel rotated to present the empty wrap to the operator standing at a hatch in the machine. Further automated operations included taping the bunch, applying a food sachet and labels. The finished bunches emerged through a small opening on a conveyor. All in all a very busy machine.
The PLC was a GE 9030 and there were six servos doing the pulling, pushing and round & round stuff. I could have dedicated a whole subroutine to the sections of program that tried to compensate for wobbly mechanicals, backlash and all the will-it-won't-it aspects of a somewhat questionable design. The whole thing was clad in stainless sheeting, broken only by the flowers-in and the flowers-out hatches and an interlocked door on one side.
The customer's sales guys and production staff thought it was amazing. It presented waiting wraps as fast as the operator could turn around and get another one to throw into the hatch. But what no one saw was the four guys who'd been secretly locked inside the machine, aranged in various contorted positions to provide "assistance" to the the film and flowers as they flew around on their tortured journeys behind the anonymity of the steel cladding.
Good news 1: no injuries(!) Good news 2: we left with cheque
I once had a job with a small company building "bespoke" machines. I soon came to realize that bespoke translated as "the ones that nobody else wants to take on".
We made a machine for wrapping bouquets of flowers and the customer wanted an on-site demonstration. Development had dragged on and they were getting a bit twitchy having put a fair amount of money into it. The machine was just large enough to walk around inside with a little headroom. It pulled in plastic film from a roll via an accumulator, fed it past a blade and presented the cut length to a table above head height. There was a vacuum belt and any number of extending suckers to handle its journey. The table could rotate to preset angles and was driven three feet along a track (while hot glue was sprayed along one edge of the film), to where one of four cones mounted in cross-formation swung round to collect it by rotating and wrapping the film around its surface (with a little help from air jets, brushes and foam rollers).
The four cones indexed round and a cylinder inside each one extended at the appropriate moment to send it downwards into the waiting embrace of an assembly of vacuum suckers mounted on several articulated arms. (loads more tiny cylinders to flex the joints of the arms, which were more like giant fingers). Four of these groups of arms and suckers were mounted on an indexed carousel so that when the extended cone had deposited the wrap and withdrawn, the carousel rotated to present the empty wrap to the operator standing at a hatch in the machine. Further automated operations included taping the bunch, applying a food sachet and labels. The finished bunches emerged through a small opening on a conveyor. All in all a very busy machine.
The PLC was a GE 9030 and there were six servos doing the pulling, pushing and round & round stuff. I could have dedicated a whole subroutine to the sections of program that tried to compensate for wobbly mechanicals, backlash and all the will-it-won't-it aspects of a somewhat questionable design. The whole thing was clad in stainless sheeting, broken only by the flowers-in and the flowers-out hatches and an interlocked door on one side.
The customer's sales guys and production staff thought it was amazing. It presented waiting wraps as fast as the operator could turn around and get another one to throw into the hatch. But what no one saw was the four guys who'd been secretly locked inside the machine, aranged in various contorted positions to provide "assistance" to the the film and flowers as they flew around on their tortured journeys behind the anonymity of the steel cladding.
Good news 1: no injuries(!) Good news 2: we left with cheque
ceilingwalker
Lifetime Supporting Member
Now that is funny! I bet it was a sight to see. LOL
ceilingwalker
Lifetime Supporting Member
Why is that Mr. Vonny? My story is the opposite. It more than doubled my salary, cha-ching!!!
Eric Nelson
Lifetime Supporting Member + Moderator
Goody
Member
When I was a young sparky, me and another sparky were sent Saturday morning to test the fire alarms at a company.
We both had hangovers from a good Friday evening session the night before.
The boss told us to test every actuator in the factory and repair any that didn't work.
All morning we walked around listlessly putting the override key into every actuator and hearing the fire alarm sirens.
I found out that by putting my upper teeth onto my bottom lip and blowing I could do a fair impression of the siren noise. I had a bit of fun with my friend by occasionally doing the noise before he had the override key in.
5 minutes before knocking off time we found that the last actuator we tested didn't work. We were both looking at each other in dismay knowing we were going to have to work over in our fragile states - when suddenly our boss appeared.
He asked us if they all were working ok.
My friend and colleague answered 'yes, all work correctly'
Our boss then said, ' ok give me the override key, I'll test one' and he went to the only actuator that didn't work.
My friend was horror-struck but in a moment I stepped backwards around a corner, just keeping my boss in sight.
As he put the key in, I made the siren sound as loud as I could.
He took the key out and said 'good' and wandered off.
We could hardly hold our laughter in having to wait until he was well out of earshot.
We both had hangovers from a good Friday evening session the night before.
The boss told us to test every actuator in the factory and repair any that didn't work.
All morning we walked around listlessly putting the override key into every actuator and hearing the fire alarm sirens.
I found out that by putting my upper teeth onto my bottom lip and blowing I could do a fair impression of the siren noise. I had a bit of fun with my friend by occasionally doing the noise before he had the override key in.
5 minutes before knocking off time we found that the last actuator we tested didn't work. We were both looking at each other in dismay knowing we were going to have to work over in our fragile states - when suddenly our boss appeared.
He asked us if they all were working ok.
My friend and colleague answered 'yes, all work correctly'
Our boss then said, ' ok give me the override key, I'll test one' and he went to the only actuator that didn't work.
My friend was horror-struck but in a moment I stepped backwards around a corner, just keeping my boss in sight.
As he put the key in, I made the siren sound as loud as I could.
He took the key out and said 'good' and wandered off.
We could hardly hold our laughter in having to wait until he was well out of earshot.
danw
Lifetime Supporting Member
I'm gettin' old
The controller is clearly labeled for a 24V power supply
But I pulled the chassis out and stuck it in a case pre-wired for 115Vac.
Bang ! !
Varistors took the hit.
Amazingly, it still works when powered properly.
Just gettin' old.
The controller is clearly labeled for a 24V power supply
But I pulled the chassis out and stuck it in a case pre-wired for 115Vac.
Bang ! !
Varistors took the hit.
Amazingly, it still works when powered properly.
Just gettin' old.
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