Modbus in ClassicLadder doesn´t work

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31 May 2019 16:10 #135480 by MATZE-ATZE-SCH
Modbus in ClassicLadder doesn´t work was created by MATZE-ATZE-SCH
Hey,

I have just Updated to Debian Stretch, the 32bit version.

But now, the Modbus doesn´t work anymore.

The Hardeware seems ok, under Windows I can comunicate with the Hosts.

But in Linuxcnc I get an communication error.

Any suggestions? The USB-Rs485 is listed, when I enter a command prompt with "lsusb"

The same I´ve got when testing the 64bit version of stretch.

Best regards
Marcel

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31 May 2019 23:55 #135511 by andypugh
Replied by andypugh on topic Modbus in ClassicLadder doesn´t work
Does the usb port show up as a serial port in /dev ?

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01 Jun 2019 09:34 #135551 by MATZE-ATZE-SCH
Replied by MATZE-ATZE-SCH on topic Modbus in ClassicLadder doesn´t work
Hey,

there show up a file called "ttyusb0", when I plug in the Stick.
Is this the right one?

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01 Jun 2019 10:00 - 01 Jun 2019 13:26 #135554 by MATZE-ATZE-SCH
Replied by MATZE-ATZE-SCH on topic Modbus in ClassicLadder doesn´t work
Had looked in the Internet for solutions and found this:

First I needed to uninstall brltty. This seems to interfere the ttyUSB0.
Then I had to open the console and enter
sudo chmod a+rw /dev/ttyUSB0
then it worked...

Does someone know, what was wrong?

Best regards
Marcel
Last edit: 01 Jun 2019 13:26 by MATZE-ATZE-SCH.

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01 Jun 2019 22:52 - 01 Jun 2019 22:55 #135592 by Grotius
Replied by Grotius on topic Modbus in ClassicLadder doesn´t work
I have just Updated to Debian Stretch, the 32bit version.

If you did that, you are a long time in the past my friend. 32 and 64 is just factor 2.

brltty is not a common used program or code. Sure not for linuxcnc.

The attached code is a example how to connect modbus to linuxcnc in python, the main script for starting up linuxcnc.
Attached also a hyperterm powermax modbuss connection, provided by the indian.
Attachments:
Last edit: 01 Jun 2019 22:55 by Grotius.

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02 Jun 2019 00:24 #135601 by MATZE-ATZE-SCH
Replied by MATZE-ATZE-SCH on topic Modbus in ClassicLadder doesn´t work
Hey Grotius,

ok, so I should update to 64 bit?
brltty was already installed with the Image of LinuxCNC, in both versions, the 32bit Image and the 64bit Image. With this installed, I didn´t get the ttyUSB0 in /dev, but after deinstall this, the ttyUSB0 showed up. But don't now why, the brltty seems for people who needs a braille attachment.

Ok, with python I have absolute no experience...
Do you think, with python it is easier to set up modbus in linuxcnc then in classicladder? The only reason I need modbus is for reading out the load on the servo drives...

Best regards
Marcel

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02 Jun 2019 00:37 #135603 by tommylight
Replied by tommylight on topic Modbus in ClassicLadder doesn´t work

Had looked in the Internet for solutions and found this:

First I needed to uninstall brltty. This seems to interfere the ttyUSB0.
Then I had to open the console and enter
sudo chmod a+rw /dev/ttyUSB0
then it worked...

Does someone know, what was wrong?

Best regards
Marcel

Yeah, that need read and write permissions while they are normally set to read only.

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02 Jun 2019 18:20 #135650 by andypugh
Replied by andypugh on topic Modbus in ClassicLadder doesn´t work
I think .so / .ko depends on kernel (RTAI) or uspace (preempt-rt) real-time flavour rather than 32/64 bit.

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12 Feb 2020 20:23 - 12 Feb 2020 20:25 #157216 by Hortensie
Replied by Hortensie on topic Modbus in ClassicLadder doesn´t work
I just documented basic modbus ladder with my RS-485 12V relay channel switch. You might check this page github.com/Hortensie/CNC_x_axis_linuxcnc...er-and-RS-485-Switch
Last edit: 12 Feb 2020 20:25 by Hortensie.

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