When you come across skullduggery.

[Ronnie Sullivan]

As the title; sometimes you don't know whether to laugh or be impressed by the 'out of the box' thinking.

I went to a special brick-making machine that had 2 pots on the panel door to change the timing of how long the mold was vibrated and how long the bricks were tamped.
One timer was erratic and the other pot only worked on high or low.

Inside was an old Mitsubishi FXon plc.
The machine was 30 years old and I suspected the pots had gone dry in that time.

There were no timers in the panel so I wondered how these pots were controlling the time?
I followed the pot wires and they went inside the plc through the side air vents ??

FX plc's have 2 onboard pots to alter values in 2 registers.
I opened the flap they are under - and both were missing.

I went online with the plc and saw the values change and jump about as I turned the panel door pots.

Somebody had desoldered the plc pots and soldered the wires from the door pots in their place.

I replaced the door pots and all was well again but?????

 

[cardosocea]

In my country that guy would be called Macgyver

 

[parky]

I have seen that a few times, the pots replaced by ones on the door, the favourite ones are label applicators where they use the pots for timing delays for the label applicators.

 

[I_Automation]

My question is why wouldn't the PLC have been designed with a plug to unplug the PLC's pots and plug in remote pots?



Or the tougher question - Why not 2 plugs so one can be changed independent of the other?

 

[muusic_man]

In my injection molding days I installed an on/off switch connected to a green light on the door of one of the molders. The switch did nothing but turn the light on. That's it. There was a supervisor who insisted the molder ran better with that switch in the "ON" position. Still there when I left.

 

[cardosocea]

My question is why wouldn't the PLC have been designed with a plug to unplug the PLC's pots and plug in remote pots?



Or the tougher question - Why not 2 plugs so one can be changed independent of the other?

Cost? Lack of vision? The pots are a nice addition (only seen then in the S7-200 myself), but were mostly for stuff that you'd have to be "competent" to modify. So most likely it is really tunnel vision from the product developer not being an industrial engineer to see the value in it. Or, it could be a Rockwell like trick to sell you analog input cards.

 

[gas]

I saw a machine that had a switch on the door, two positions normal and fast. It wasn't even wired. The foreman insisted that it ran faster and better on the fast setting.

 

[I_Automation]

I saw a machine that had a switch on the door, two positions normal and fast. It wasn't even wired. The foreman insisted that it ran faster and better on the fast setting.

I had to add a switch on a door to run a room humidifier with a bad flow switch on the HVAC duct.


When the flow switch was fixed I disconnected the toggle switch , but left it.


I had to search almost every language that uses the Latin alphabet in Google translate to find one with a word meaning idiot that wasn't idiot or some obvious reference (Idiotta, etc)


I finally found in Filipino "Idiot Test" translates to "Tonga Test" and that switch is still labeled that to this day and the line leader turns it on every day.

 

[g.mccormick]

I had to add a switch on a door to run ...

...I finally found in Filipino "Idiot Test" translates to "Tonga Test" and that switch is still labeled that to this day and the line leader turns it on every day.

That is evil and so funny.

 

[tdoa]

I saw a machine that had a switch on the door, two positions normal and fast. It wasn't even wired. The foreman insisted that it ran faster and better on the fast setting.

Seems like a variation of the magic and more magic switch from the old days:
http://www.catb.org/jargon/html/magic-story.html

 

[I_Automation]

That is evil and so funny.

There was a loader (I never worked on, just near)that took panels off a rack and placed them on a conveyor. It had a speed pot on the control panel that would either run too slow and reduce production or or too fast & double up product that the operator kept playing with.


The technician for the department said he finally fixed that - he disconnected the panel pot & hid a pot inside the frame of the machine.


The operator adjusted the old pot at least every hour.

 

[OkiePC]

I worked in a paper plant that had a baler in the corner where they always staffed it with new guys. There was a button next to the HMI with a professionally engraved label that said "DO NOT PUSH" If they pushed that button nothing happened except the ear piercing alarm horn would sound for 30 seconds and could not be silenced. 3 out of 4 "new guys" pushed that button. Everyone in the plant knew they did it too. I admired the guy who installed that button, but it wasn't me.

In the tire plant where I started in this career path, we had a technician who was not known to be a go getter, nor for his electrical savvy. I was walking with him alongside the ply-cutter area and an operator stopped us to thank him for "That timer you added works great, thank you."

I gave Dwayne a puzzled look after the operator left. He grinned and opened the panel door to show me his work. It was a timing relay with a coil and neutral and no wires on the contacts, but the little LED would flash and it was a knob to dick with. He'd told the operator that it would help him with vacuum issues on the transfer head at the beginning of a new roll of stock.

So the operator...instead of screwing up panelview settings that actually did something, would open the panel door (against the rules, but whatever) and dick with that knob and by the time he got it where he thought it worked best, he had worked past the troublesome lead and tail ends of the stock.

Dwayne said "That's how you deal with a knob dicker. Give them a knob to dick with that does no harm."

 

[danw]

This is the kinda thread that makes my day. Thank you all. Dan

 

[lostcontrol]

This is the kinda thread that makes my day. Thank you all. Dan

Me too, have chuckled at every one

 

[Ronnie Sullivan]

A company dismantled a dinner plate machine that molded plates from clay, dipped them and then fired them. It was a very long machine and they moved it to their other factory.

When it was reassembled, it would not start.

They told me they had, had electricians check every connection and all seemed ok.
The huge panel door was caked in dried on clay with loads of buttons.
I pressed a few and was told 'we already did all that.

Most of the button decals were covered in crud and unreadable.
I cleaned a few and one read 'RESET (HOLD FOR 2 SECONDS)

You guessed it - it started.