1979 Vintage Cerutti Printing Press

What's it gonna take to put you on the control panel of this shiny new machine today??

http://www.cerutti.it/en/home/products/rotogravure_printing/R98X

...might be able to find something here....

http://www.bohemia-grafia.de/en/machines/print/roll-roll/gravure/000505-rotogravure-printing-cerutti-r28-11-units

What type of press? Individual unit controls consisted of ink viscosity, registration control and web break detection systems. Does the press have a drive shaft common to all units?

I cut my teeth in a large rotogravure shop that had 5 press lines and one of the lines had some Cerutti units and a Cerutti folder mated with 4 Goss units.

Can you still operate the machine on a test run with this module in/out, or powered up/powered off?

Would that tell you what it is doing? IHNI...so I will be quiet now.

Is the transfer function a flying splice at the web infeed, or a flying web cutoff to start a new roll at the rewind? Do you have the electrical schematics for the module? Is the module just a circuit board or a series of individual components (relays, timers, switches, solenoids, etc.)? Is there a PLC involved? Ladder logic? A few more details would be helpful to try to help you out.

Thanks for the replies. I wasn't sure if I would get a response. Here is the deal. I have several of these printing presses dating from 1979 to 2012. The newer ones not only have more modern electronics, but they go much faster than the older ones. Unfortunately, upgrading the old electronics is not on the table.

The module in question is known as a 51041 with the name listed as a "Reazione Di Tensione-Correntte" which I believe translates to "Reaction of Voltage-Current". Unfortunately that is not very descriptive for what it does but I may have access to one that works correctly. That is yet to be seen.

It appears to be strictly analog. This circuit appears to operate a roller known as the "dancer" which helps to keep tension on the web when there is a mismatch between the feed rate of paper into the press, and the general speed of the web. There is apparently a couple of missing signals because this subsystem has been abandoned for a while. I'm guessing it can be very touchy and cause more problems than it helps if the circuit gets out of adjustment. I'll get to the details shortly.

The circuit board is a standard size 3.84" by 6.94" and consists of mostly op amps with summing junctions. I'll see if I can insert the circuit drawing in the next post, but I have a meeting to go to right now. Back to you shortly.

Back again. The first two photos will probably not be very helpful, but it does answer some of the questions.

The transfer function looks something like this:

Just so you know, the guys that came up with this are long retired and unavailable. The new guys use something completely different which I have not seen as yet. I'm at least half a day away from the facility so it makes it a little bit difficult to ask questions. And on top of that, many of the questions I have asked just result in a blank stare. So, no help there.

That relay that is marked fast/slow actually drops the gain in one amplifier and it is used during normal operation. Beyond that, there are a lot of unanswered questions.

The "Dancer" has a metal rod that is inserted into a coil at one end of the stroke. So far, no one has been able to describe what it does and when so I guess I'm just going to have to climb up on top and have everyone else turn their heads while I'm looking to see for myself. I know that this system is a crude version of an LVDT (sensor) and it is mostly linear but it has no temperature compensation like LVDTs of today have.

The thing I dislike the most about this is that it was all turned over to a maintenance department who only knows how to swap modules. I can't easily tell what "normal" is supposed to look like. The controls and the press are separated by a wall. Lastly, in 1979, very little was being done to suppress RF noise which radiates from the control panel at a level that I have never encountered. I'm not allowed to fix that either. At least, not yet. That noise comes from the conversion of 3 phase AC to DC with no filtering capacitor what so ever, and some sort of SCR to run DC motors.

I've asked what the I/O pins connect to (as in the next module) and nobody really knows. It seems that the one guy that used to know that died and took that job security with him. But, according to the locals, "He was a really nice guy!"

To make that worse, it seems that some of the equipment that related just to this card has been removed and it just happens to be the only module affected. So, now they just web around this "dancer" and try to work around it. As long as the paper is heavy enough, they seem to be able to get away without using it. It seems to be just one of those things that happens when people leave or die.

It makes me feel a little bit like the accountant who when asked what 2 + 2 equals, he responds with, "What would you like it to be?"

From what I've seen, a lot of these analog modules are carefully tuned dead art. Many of the components from diodes to op amps used back then do not match up very well with the more modern versions of the same part numbers. Even though the same parts (by part number) are available, they are too different to be compatible with the older electronics. Attempts to "repair" a board just results in an "out of control" response.

Like I said, no one seems to know what "normal" looks like, much less where the inputs and outputs actually end up going. SOSDD! That means SOS, different day!

I will reply with more info this evening.

Great description! That sounds exactly like what is supposed to be going on. I think the approach that I am studying is a little different, but I can tell that it is a well tuned circuit because nobody seems to know if certain modules are bad or just out of tune.

The digital world is a blessing. It allows one or more software considerations to be available at the same time. These analog devices only have one chance of working correctly in certain devices.

Many thanks for your help. I gave you a G.A. for your efforts.

My pleasure...

Duh... I forgot to mention that the output resistance of the pot attached to the dancer is also an input.