Deckel Maho NC Integration

I have a Deckel FP5NC Dialog 3 machine that is fully functional. I intend to upgrade the machine to LinuxCNC in the future and have been researching the project for some time. A number of people have completed the conversion, demonstrating that is is very feasible. I would like to make this thread a repository of the information everyone has gained in converting their machines.
I realize there can and will be a million combinations possible but would like the primary direction of the thread to be

'Integration of LinuxCNC to Deckel / Maho / DMG type machines using existing hardware'

LinuxCNC control using original hardware:
Servo drives / amps
Spindle drives / amps
Position feedback (typically 20 micron glass scales sin/cos)

Here is information I know about my FP5NC machine:

DC servo axis drives, tachometer feedback, driven via Bosch TR25 amp
Accepts ±10VDC speed signal
DC 7.5 Kw spindle motor driven by BBC amp, variable speed
Unsure on speed input signal
Direct position feedback from 20 micron glass scale, output signal is sin / cos (resolver)
I will be using an IC Haus converter; TW28 Factsheet
Scales have home index position.
Spindle is driven via a 6 speed gearbox? I researched this but did not write down what I had determined......
Use PLC to operate the 3ea. gear shift motors and feedback micro switches?
Machine axis' have limit switches (micro switches and 3ea. position ramps)

I intend to use the bottom half of the existing control console with all the existing controls:
System Enable / Disable buttons
Mode rotary switch
Feedrate override rotary
Feedrate rotary
Spindle RPM rotary
Forward / Reverse / Stop buttons
E Stop buttons on console and MPG pendant
X Y Z C Jog buttons
Axis lock toggle button
Jog rapid override button
Lube and Coolant buttons
Cycle Start / Stop buttons
Horizontal / Vertical spindle operation switch
MPEG pendant with axis select and 3 rate select buttons

I want to keep the mode select knob with discrete rotary positions to select the various mode pages to be designed into the interface.
Not sure how the switch is currently wired but would like input on how to best transmit the selected positions minimizing input ports used.
I will use potentiometers for the feed and speed control knobs.
Are the lights in the pendant switches turned on via a response from the controller or simply a mechanical switch within the button? I assume the smart way to go is for linuxcnc to light the switch, verifying the selected action.

I already have the TW28 boards for doing the glass scale conversion and would like input on the additional features of the chipset that could be used to optimize the encoder side of things. I'm no electrical engineer, more of an integrator....... so hopefully some of you EE type will chime in with ideas.

gernoff wrote:

I already have the TW28 boards for doing the glass scale conversion and was interested input on the additional features of the chipset that could be used to optimize the encoder side of things.

Does TW28 come in board form or you getting just the chip? Whats the cost of these?

Those look pretty cool.

Yes, they have an evaluation board available. IIRC it is around US$100.

Hi Gernoff!

The wiring of the switches in the D3 console is described in the schematics Orange Book for the D3 machines, and luckily there is a complete scan of that book here:

sites.google.com/site/deckelnc/

Cheers

I have asked IC-haus with the same problem. The have highly recommended a much simpler interpolator Chip.
The NV isn't programmable, but can hardware switched to the desired resolution. One of the Chips is under 10$.
The evaluation board, is about 75$. But its not really necessary, because the complete circuit diagram is printed
into the documentation.

TW28 has 2 ways of configuration. It can be configured using SPI to take full advantage of all of its features. or it can be configured using static pin-only mode. Pin only configuration allows a subset of features and interplation factors that are most commonly used. The advantage obviously is the simplicity, no programming required. Pin-cfg also allows auto calibration to be used, which is a key advantage over iC-NV, for example.

Finally have a chance to get back to the linear scale integration project. The suggestion for the 15 micro amp output is to:
'But a simple current-to-voltage converter will do it, for instance biasing each input with a voltage divider (e.g. 2x 25k) between 3.3V to GND.
This terminates the 11 µA current output and delivers 437 mVpeak (by 12.5 kOhm). As the level does not undershoot 1V, I think it's not a problem for the sensor's output.
Is the following sketch what is being described above?



Thanks.

Are these Heidenhain encoders? How did Deckel interface them? MAHO used Heidenhain EXE's, and I would suggest you do the same. I just got one off eaby for €64, and it has the correct connector for the Heidenhain cable, and worked perfectly once connected with the MESA 7i77.
Mark