Retrofitting Maho MH600E 1989 - Meas 5i25 & 7i77

Now that i´ve finally got the 7i77 running to a point where i can sense inputs and set outputs I´ve went on to the cabinet on the Maho.
The first task was to pull the heavy thing out of it´s corner in my shop. I mean it´s not that heavy, but very uncomfortable to move.

With the blue pallet jack you can lift the machine quite good when you attack it from the controlmonitor side.
So i´ve pulled the machine away from the walls so i can open the cabinet door all the way.

I´ve started with unplugging all cables from the "PC" and I´ve tried to see to what part they are connected.
The 3 Glasscales are easy to find and I´ve tucked the three cables to the side for later inspection. From the rotary Thread i´ve read that you can use the old EXE board for TTL signals, so this board got safed at first.

I´ve unplugged the ribbon cables that are connected to the relais board and will check how RotarySMP salvaged this.
On the very botto right corner of the cabinet is some weird terminal block, that connect the Maho MPG, the "PC" and the relais board. I´ve left that untouched because i´m not sure if i could reuse that thingy.

So far the main PC is out of the machine and my next tasks are to check alle the relais and their function according to the e-plan and check how to interface the relais board and the TRM 2

OKAY I`VE TRIED TO ADD PICTURES FOR 10 MINUTES NOW. I`M FREAKING OUT.

could someone suggest an easy and fast way to add pictures ? with thumbnail

Onkelmat wrote:

From the rotary Thread i´ve read that you can use the old EXE board for TTL signals, so this board got safed at first

I found these chips recently, but I have not had a change to try them yet...

sine/cosine converters with selectable interpolation.

de-shop.ichaus.com/encoder-circuits/inte...ion-sine-to-digital/

@onkelmat
Use the action button and therein reply.. Under the box there is arrachements. Chose your image and insert.. With the preview on top of the box you can control in preview.
Mike

@Mike thanks for the tip, gonna try
@opw nah, rather use the already built stuff would need a custom pcb

So i´ve mounted the PC inside the cabinet and removed the old control.
Next i´ve started to analyze the relais board but unfortunaly the shematic i wanted to use are not even close to the board i have.
So yesterday and today i´ve measured across the board to check wich pin drives wich relai but thats no fun at all.

Soooo long way. My expansion card 7i84 came today with dhl express. Gonna use it for the gearing.

After a quick call with MAHO in profonten I got some shematics fitting my machine. Everything makes sense now

I´ve written down all pins that control important parts of the machine.
But what´s the difference between "NC start" and "NC bereit"?

Tomorrow i´ll start wiring the parts to run the hydraulics and maybe the toolchanger.

ja schon klar ^^ aber wo liegt der Unterschied ?

With the original plans I´ve started to try to latch on the machine. Seems like a little riddle Maho made up.
The first problem was, that that i wanted to source the 24V+ Logic Power from the machine and not from an extra powersupply. So I´ve searched the source of the intern 24V power line. It comes from The 7K2 and 7K3 line. But you have to energize them with the lighted Button on the Controlpanel, while holding the button you have to latch 19K1 wich is on the relais board and is powered by the 28x1 Pin 2 that is energized by the 7i77. The 7i77 gets it 24V from "Reihenklemme" 202 that is energized from 7K2. It´s a selfholding line.

So...this is the routine:
Hold lighted Button on control (next to emergency stop) -> 24V to the 7i77
Start Linux CNC
set machine enabled (give power to the 28x1 Pin 2 to latch 19K1)
If everything is ok, the 24V line should hold itself now.

Actually that did not work right out of the box, There is K1 in the line that is activated when no emergency stop is pressed and the drives are "ok".
So the machine did not latch at first. I´ve bypassed the K1 and it worked. So my task for tomorrow is to find out why K1 won´t do it´s job.

I'm not in Maho but generally speaken:
I wan't in any circumstances have my control logic under power. So i can read/see the status of my sensoric always. Specially when something goes not the way i expect.
On the output side it is a bit different. There i want to be able to stop dangerous things surely stopped when estop is pressed. But nevertheless there might be activities that i prefer to have, like signalisation lamps. So generally cupping 24V. I dislike.
On the power side it is a bit trickier, normaly people tent to cut directly from the grid. This can be dangerous for some vfd's when there is mass plus movement. Also most vfd's when switched to max breaking stop faster against mechanical hazzards then going into free run. A typical arguments for estop is electrocution, but in reality I see more the need for fast stop of unwished moving. That's why i prefer a timer that keeps power after estop for a few seconds.
Result of that long sermon is the proposition to sit back and define yourself the wished behaviour of your machine. Than start optimization of your electric. And keep it as simple as possible. Eliminate every part you can.
M5c Mike

I haven't quite followed how you power the mesa card but in general you want to avoid cutting field power to the mesa cards as it can damage the output drivers.

forum.linuxcnc.org/27-driver-boards/3782...ugging-advice#150491

Yes, the 7I77 field power should connect directly to the source, Its ok to break the
connection (say with a fuse or circuit breaker) but it should not be switched on through
a relay or mechanical switch. This is the same with most DC powered devices (step motor
drives etc) because both the power supply and the powered device have bypass capacitors
and very high surge currents can flow between these when switched on instantly.