this topic is grate so watching this closly to see how you solve this
i also have a nigribosi machine around 1998 eara , before they went full PLC type etc currently the conotrol keeps needing TLC on its many PCB boards due to age and drift , always down to the way it monitors position and control of its rams
in this machine there are a number of proportional valves , i looked at other controls out there but they are mostly aimed at VFD driven pumps and not many proportional valve outputs
mine has two proportional on the pump block
one for Flow and one for pressure , these work together during differant operations during the cycles to keep energy use down etc
also when the machine is first turned on, they use the platen valve block and pump in full flow to heat up the oil faster so no preheaters are needing only the pump is used.
valve on the screw carriage to control distance and speeds seems to be a standard vale and they must use the pump to control the speed in pump flow. and they seem to do this for afew other things, where only 1 thing works at one time,
one on the molding machine platen is proportional doing distance and speeds for the multi point open and shut speeds and distance for open and close strokes, this would be due to the fact you can do ejection while platten is still opening by seting the 1st ejectoin distance start
also one on the ejection plate to set the distance and speed for ejecting the part from the mold must be a proportional as works during the high flow high presure on the plattern if enabled to eject during open stroke.
looking at it, the same seems to be on the screw for the screw speed control, not sure how they are controlling the back pressure on the screw and screw injection profile settings.
i had through about using linuxcnc also as alot can be done in hal easy, not that much to address in a molding machine, more how you control its cycle in its little fucntion blocks as such.
mine has a safty relay for the estop buttons , not sure what else they routed through it
for safty guards, they seem to read these in on the control, the ones on the guard door and must work in the corrrect sequence when opening or closing the door or it does alarm out with guard out of sequence, i assume as on this machine you can move the safty switch and open the door extra day light which is good for loading in bigger tools over head
the control also has options for things like core pullers normaly 3/4 can be used
also air ejection is on this machine
also ability to read thermo couples from a mold tool
also the control also controls the hydrulic tank temp but turning on and off a valve that pushes the oil through the heat exchanger for cooling from the cooling water coming into the machine.
as already pointed out, alot of the machine works on timers and waits for one section to finish before it starts the next, is alot the user can input and change during the machine working cycles. also a good handfull in the machine setup pages that are fixed like time out for screw back and screw injection etc, along with max presure for platten open and close
they seem to be Bosh or Atos alot for the valves i find in nigri bosi
lube cycle tends to be done on the number of completed ejection cycles
i do have some wiring diagrams and hydrulic i can share if it would help in understanding , can also share some control screen shots for reff