MDX-20 communication issues

Warranties, repairs and maintenance
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montd
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MDX-20 communication issues

Post by montd » Fri Jan 04, 2019 8:05 pm

Hi all,
Recently I have become a (mildly perplexed) owner of a Roland Modela MDX-20. After reviewing few instruction manuals I got myself a serial to USB adapter (Unitek) and set up a connection with the modela. I have made sure to enable hardware control and everything should be fine on software side. However:
  • Both buttons "UP" and "DOWN" instead of regulating height of Z axis after pressing cause the spindle to spin for 5 seconds
  • Simple instructions sent with this user made control panel https://github.com/chriskyfung/modela_m ... nel_scilab are properly interpreted and realised, same goes with manual XY positioning in Modela Player 4
  • When sending toolpaths from Modela Player 4 the device moves quite differently than planned in program, adding a bunch of unnecessary movement and finishing the run after less than 4 minutes
What I did to troubleshoot:
  • Reinstalled the drivers of both the machine and Unitek serial adapter
  • Checked the serial cable supplied with the Modela for correct pinout with a multimeter
  • Modified the settings of COM port: changed the number between 1-3, played with buffer size and so on, mostly with even less success in communicating
  • Opened the case and examined the PCB and wiring - no signs of decay, the connectors looked good
  • Tried to update the software on Modela (quite crazy you have to rearrange the jumper wires to do so!) but the program stated it's up to date.
I would be most thankful for any assistance with the subject!
Currently my only idea is to purge the PCB and proceed to install arduino board along with some controllers, but that would be counterproductive if there's any chance of preserving the device as is.

Best of wishes.

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Kai Perry
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Re: MDX-20 communication issues

Post by Kai Perry » Mon Jan 07, 2019 10:10 am

Just check that you are definately using a serial cross over cable and then an USB to serial adaptor cable.
Kai Perry
Application Engineer
Roland DG (UK) Ltd
http://www.rolanddg.co.uk

duncanerobinson
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Re: MDX-20 communication issues

Post by duncanerobinson » Mon Jan 07, 2019 9:51 pm

I have an issue with my MDX 15... Is the serial to usb connector a Prolific chip based connector?

montd
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Re: MDX-20 communication issues

Post by montd » Mon Jan 07, 2019 10:40 pm

Kai Perry wrote:
Mon Jan 07, 2019 10:10 am
Just check that you are definately using a serial cross over cable and then an USB to serial adaptor cable.
Thank you for the response, while I do use both a serial cross over cable (pinout checked manually with multimeter) and an USB to serial adaptor I will check a different configuration - maybe the errors come from that.
However that doesn't explain the odd spindle behaviour when pressing the "UP" or "DOWN" buttons on the machine itself... What might be the reason of that?
duncanerobinson wrote:
Mon Jan 07, 2019 9:51 pm
I have an issue with my MDX 15... Is the serial to usb connector a Prolific chip based connector?
It's this one: https://www.unitek-products.com/product ... uct&id=131 and the chip from what I can gather is indeed Prolific. Have you tried a different chip with any success?

Kind regards,
Michael.

duncanerobinson
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Re: MDX-20 communication issues

Post by duncanerobinson » Mon Jan 07, 2019 11:28 pm

Our local IT guy suggested that you may get signal degrading over long cable length.

Having similar issues here too, so feeling your pain. With our z axis, the spindle doesn’t change height for approx 3 seconds when holding up or down, but does spin during this time. Have you tried holding down for 10+ seconds?

duncanerobinson
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Re: MDX-20 communication issues

Post by duncanerobinson » Mon Jan 07, 2019 11:30 pm

Am using this lead, about 20cm long:

https://www.amazon.co.uk/gp/product/B00 ... UTF8&psc=1

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Kai Perry
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Re: MDX-20 communication issues

Post by Kai Perry » Tue Jan 08, 2019 10:12 am

Get a serial crossover casble and connect that to the usb converter.
Kai Perry
Application Engineer
Roland DG (UK) Ltd
http://www.rolanddg.co.uk

montd
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Re: MDX-20 communication issues

Post by montd » Sat Jan 12, 2019 1:48 pm

duncanerobinson wrote:
Mon Jan 07, 2019 11:28 pm
Our local IT guy suggested that you may get signal degrading over long cable length.

Having similar issues here too, so feeling your pain. With our z axis, the spindle doesn’t change height for approx 3 seconds when holding up or down, but does spin during this time. Have you tried holding down for 10+ seconds?
Thank you, I had no idea the button works with delay - now it's fine, although not precise at all. But that's solved. I have bought a FT232 chip based usb to serial convertor and after I'm finished soldering I will let you know if there's improvement.
Kai Perry wrote:
Tue Jan 08, 2019 10:12 am
Get a serial crossover casble and connect that to the usb converter.
I will be soldering my own cable along with proper usb to serial convertor, is there any semi-official reference of correct pin connection?
Also is "crossover cable" same as "null modem"?

I managed to make a successful test run from linux using the same serial convertor that did not work before on windows. What I did is:
1. set certain parameters for the serial connection (9600 bits per secon, hardware flow control also know as RTS / CTS)
2. export .prn toolpath file from Roland Modela Player 4
3. send the file directly through serial connection
That has worked and the machine finished without errors.
However I was not so successful with replicating that using any windows based terminal (putty or Tera Term).

In conclusion:
Windows drivers or printer management might be the bottleneck and direct serial connection needs to be established.
I will report on any more findings to help others with same issues.

Kind regards,
Michael.

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Kai Perry
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Re: MDX-20 communication issues

Post by Kai Perry » Mon Jan 14, 2019 10:21 am

The crossover cable is a null modem cable, you can also purchase an ME3-USB cable from your local Roland office which has drivers for the MDX-20 - http://download.rolanddg.jp/en/3d.html#meus3
Kai Perry
Application Engineer
Roland DG (UK) Ltd
http://www.rolanddg.co.uk

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