Copyright © 1998-2017 Luca Gallina

Runmode, programming Siemens PLCs

Free tools, hints, tips and tricks. Interesting and specialized applications are also on sale, all developed by programmers for programmers.


Automation humor

Colleague marriage

I am the author of the joke. I used a white carton box on which I painted a Siemens OP3. I added also a more convenient "break" push button, enhanced with a salami and a flask of wine (traditions are important!...). In our Veneto language (some words similar, many words very different from Italian), "viva i spósi" stands for "long live the newly weds".

The unique, genuine programmers' chewing gum!


I must admit I laughed so much I almost fell off my chair when a colleague offered me this chewing gum! I don't know whether they're distributed also abroad or just in Italy, in that case I seriously believe I could start a business selling it to programmers worldwide...

True stories

from my personal experience or that have happened to friends of mine. I obviously omitted the names, but I guarantee that the anecdotes are absolutely true!!!


Words (September 2010)

At a customer’s office, a colleague and I were busy analyzing a WinCC 7 communication problem.  In the corner of the office a radio was softly playing music.  While focusing on a protocol issue, we started laughing as soon as the radio started playing a 1982 song by F.R. David: “words don’t come easy to me, how can I find a way...”


Einstein-like colleague

"No bug is created, no bug is destroyed, all is transformed"


Heisenberg’s sub-atomic particles ”uncertainty principle” applied to bits

Customer tech: "...we need some help, we got a flag which is not TRUE nor FALSE"


Joke request to newbie programmers

"...bring me the wireless cable, you find it in my desk drawer "


Esoteric troubleshooting (May 13, 2003)

Hard to believe, but absolutely true!!!

Despite more than 18 years spent on field as tech and programmer, probabily I hadn't seen enough... well, until yesterday! I could not believe my eyes when a technician came to a machine I was modifying, and with a divining pendulum began to look for the machine problems. At first I thought it was a joke, it took me a while to realize he was absolutely convinced. The "magician" (this is how the plant workers called him, as I discovered later), after holding the pendulum over different places around the machine, stated that the machine had "hydraulics problem" and assured the workers that, after my work on the PLC program, the problem would be solved...

The "magician" reminded me of another long forgotten episode in south-east Asia where, due to a faulty closed-loop controller, a machine performed weird operations at random times. A colleague of mine found the factory workers offering food and other things as sacrifice to the machine, for they thought it was possessed by demons...


smarter than a limit switch

A shuttle driven by a common AC motor does not stop exactly in position.

Manufacturer: "The shuttle is not stopping exactly in position"

Programmer: "Yes, that's due to the shuttle mass inertia, you must change the limit switch placement to compensate the inertia stroke"

Manufacturer: "Can you prevent this by modifying the software?"

Programmer: "Unfortunately not, I am already stopping the shuttle as soon as the limit switch trips"

Manufacturer: "Why can't you detect the limit switch BEFORE it trips?"


Pump does not run

Phone call to a PLC service technician

Service Technician: "Hello, this is the XYZ technical service, what can I do for you?"

Manufacturer: "I am using one of your PLCs. But my machine doesn't work...the pump doesn't run"

Service Technician: "Is the PLC correctly powered?"

Manufacturer: "Yes, it is. But the pump does not run"

Service Technician: "Is the CPU in 'run' status? Are all LEDs' ok?"

Manufacturer: "Yes, there's a "run" LED on"

Service Technician: "Have you downloaded the program?"

Manufacturer: "Program? Which program?"

Service Technician: "The PLC program! Didn't you develop your application program?"

Manufacturer: "A program? I don't know anything about a program. They sold me the PLC saying it would ran my machine, that's all.. But my machine does not work, the pump doesn't run..."


Program price: 9.99 Euro/Kg

A programmer developed a nice and compact S5 PLC program which needed less memory and ran faster than other programs on similar machines

Manufacturer: "I am not paying you the money you're asking for"

Programmer: "Why not? I developed a functional program"

Manufacturer: "Yes, but it's only 2 Kbytes long. You're trying to fool me, another programmer asked the same money for a 8 Kbytes program!"


Watch for snipers!

(Happened some years ago, when a small factory owner bought his first PC)

"Oh, we bought a PC! It came with a monitor, a keyboard and a MAUSER"