What exactly does the Durst STA-450 timer/stabilizer do?

[chuck94022]

Inspired by Polyglot's Arduino-based f/stop timer (see http://www.brodie-tyrrell.org/fstoptimer/), I'm building one - leveraging his software and design insights, but updating it in a number of ways to be revealed if I ever release it (as an open source project).

I have a Durst L1200 with a CLS450 color head. Powering it is a TRA-450 power supply, connected to a STA-450 Timer/Stabilizer. I would like my timer to work with this system, since it is the one I use every day.

What I'm wondering is what precisely the STA-450 is doing in addition to exposure timing. Is it regulating time or power? Is it operating based on feedback from a sensor in the color head? Is this feedback something my timer has to account for?

Thanks for any help from knowledgeable folks.

-chuck

 

[AgX]

I have NO knowledge about these items, the designation "ST" though seems to refer to a stabilizer.

BUT if I look at the backsides of the two items, it rather seems that the TRA has a standard european 220V socket (though likely with unknown-to-me safety insert) and a male 220 cold-utensil socket for the timer output. The ST seems to have a flat (earthless!) 220V plug and a female 220V cold-utensile plug.

With such wiring I cannot imagine how the ST could do any stabilizing, but just be a plain timer. With the 220V outlet at the TRA making a second wall-outlet for the timer superfluous.


TRA

ST

 

[chuck94022]

Mine is identical except the power on the TRA-450 is US 110v. The mystery to me is what the 12 pins going to the color head are doing. In the mean time, I'm ignoring the complexity, and just connecting at the focus plug on the STA-450, which will do exactly what I need.

 

[AgX]

The 12-pins plug is for the 24V/250W for the color-head lamp, maybe more voltages for accesories.

 

[Prof_Pixel]

Constant voltage transformers were standard when doing color printing. Google 'constant voltage transformer' for more information.

 

[AgX]

Look at the wiring, it does not make sense, in this case.

Though it could be that the timer when used alone, at his female "enlarger" socket provides a stabilized net-voltage. but at his female cable plug only a switching signal for the transfomer TRA, when used as combo.

But why if intended to be used as stand alone timer/stabilizer too, it got that fixed female plug cable. Which in that case makes no sense at all.

I guess someone informed should chime in, or we need a circuit sketch.

 

[Marco Buonocore]

You can use any timer with the CLS450 and the Durst TRA-450 - it does not have to be the ST-450. I have attached my Darkroom Automation Fstop timer, as well as a cheapo Saunders IC Timer, to the TRA-450 and both work fine. Note this is for black and white printing; I do not have experience with colour printing. Perhaps the stabilizer is needed then.

I had a manual for the ST-450, but gave it away with the unit. It didn't contain a lot of useful information. It was as poorly written as the timer was clunky!

There is a wiring diagram for the Durst TRA-450 online at http://125px.com/docs/manuals/darkroom/durst/

 

[paul_c5x4]

The 12-pins plug is for the 24V/250W for the color-head lamp, maybe more voltages for accesories.

Add to the list: Power for the cooling fan and back lights on the CMY dials. There are no sensors inside the CLS450 head, so no need to worry about feedback loops.

 

[chuck94022]

Thanks Paul, that last is precisely what I needed to know to go forward with my design.

Marco, your post is helpful too. Actually, my STA-450 hums. It has its own transformer inside (which seems redundant to the TRA-450, but whatever...). That transformer is old and I'm sure the plates are delaminating and thus the hum. I'd be happy to not use it at all, but I do color as well as B&W, it might be better to either restore the transformer (relaminate the plates) or find one that doesn't hum on e*ay.