linuxcnc + press brake retrofit with servo proportional valves

Hi guys!

I have a few old machines with dead controls, one of them is a press brake with fully functional hydraulics but the main chip was defective. For the sake of learning linuxcnc i am trying to retrofit these machines, now it's time for the press brake.As i've done my homework, i found out this system is driven by a proportional valve which receives a given voltage to let the hydraulic be fully closed, or open.For this i've been searching a mesa card that can provide this analog output, and couple it with a linear encoder, to better tune the movement of this new "axis".Although this seemed simple at first, after opening the press brake i found the proportional valve is "many valves" and i can't seem to find a way to "hack" into this system and add my own connections.I found out that this is driven by a bosch PL6 0811405060, but i'm not sure as to what all the valves are doing.There is also a panel of resistances which have a label matching each of the valves near the hydraulic pump, so i can figure they are related.There are not any manuals available for the press brake, so i'm trying to get some hints on the web as to what i could do to start this retrofit ! 


 

no, i don't have any information on the machine...

So you are suggesting that although the proportional valve will enable it to open/close proportionally to the applied voltage, the other valves might be allowing for different speeds of closing/opening?

i was thinking maybe if i generate an analog signal with mesa card and control the servos i can get it to work, but what i'm having trouble figuring out is all the other electronics and what do they do.

i'm sure the main board is the only damaged component but are no replacements on the market as it is quite old.

the mechanism being used in the proportional is this one: www.kanflu.com/assets/Uploads/SERVO-VALV...FEEDBACK-RE29028.pdf

yes, this bosch board is good. what wasn't good was the main control board where you put the cnc code

i see what you mean, there are several amplifier components inside.

but in that case, what would the other valves do?

i'll try and find enough docs on the bosch board and try to simulate the signals that the main board should send to this bosch controller, to try to simulate the system. this will be complicated!

Bosch makes complete valve assemblies for press brakes, maybe you can find documentation of a similar system. My press brake has a similar valve assembly, which is connected to some sort of servo amplifier (a different), which takes a 0-10V signal from the numerical control IO board. The rest is mostly self-contained, so the valve block doesn't need a bunch of IOs, just one or two IIRC. So I wouldn't be surprised if this Bosch PL6 0811405060 also takes a 0-10V signal.

If the original control is still around you could do some forensics on the control board and look for DACs and voltage references.

manuals available here store.boschrexroth.com/Hydraulics/Electr...11405060?cclcl=en_US

it seems to take indeed 0-10V or +-10V inputs (selectable?)

yes,, this is my best guess. try and connect the original board and look for anything that might work, to try and adapt it to a mesa card.