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For information, and in case it gives somebody any ideas. I started looking at the mesa_modbus.c.tmpl code, and modified it to output its internal state as a HAL pin. Attached a screenshot from halscope where the state is visible alongside the jump in position-fb.
 

The states are defined by:
So, we start in state WAIT_FOR_DATA_FRAME, then go to RESET_WAIT for a few cycles, and the in either state START or WAIT_FOR_SEND_BEGIN, the jump in position-fb occurs.

tommylight wrote:

Transistors should work, probably better low side, but do add a resistor between the Tang output and transistor base, something like 470 Ohm or 1K should be OK for normal signaling transistors.
Also, normal transistors do not require resistors between base and emitter for normal switching, MOSFET's do.
 

They normally don't, being current controlled devices, but I have seen instances of ghost activation in noisy environments (transistors do have a Miller capacitance, it's just much smaller electronics.stackexchange.com/a/95984). For prototyping I don't usually bother but if I'm ordering up a board I will add them since they're basically free.

Yes I forgot the base resistor!!!

Transistors should work, probably better low side, but do add a resistor between the Tang output and transistor base, something like 470 Ohm or 1K should be OK for normal signaling transistors.
Also, normal transistors do not require resistors between base and emitter for normal switching, MOSFET's do.

Normally after installing the 2.9.3 ISO, you should do
sudo apt purge linuxcnc-uspace
sudo apt install linuxcnc
then after reboot hold down the shift keys till you get the GRUB menu, there choose advanced options and select the one with RTAI in the name, enter.
Did you do this last step before testing?

here they are, take a look... component is not finished yet... I will upload them when I will have an update ...

.xml config are only for this configuration... but it is clearly vissible how it works... where what is and timing are very important

setup from my attachments has about 330us scan time on profibus which are less then 1ms for lcnc default scan time period ... there are 4 slaves

Some things to consider:
-what thickness material?
-what would be the biggest angle?
-what plasma source and torch do you have?
-
Pretty sure the torches and other stuff for angled cuts are different and use more pressure, but i never checked that, it is just a thought so far.
I would guess up to 8 or 10mm it is OK with normal stuff, some can probably do more, but as a reference cutting 10mm thick plate at 45 degrees is close to cutting 15mm plate normally.

No, IRQ pinning is different. Both are needed for best latency.
(note the IRQ pinning needs isolcpus set in the kernel command line)

I'm curious and maybe this has been answered before, But in QTplasmac I import my part that was created in Sheetcam it has the settings in it for material and cut information but QTplasmac has a drop down for the material as well. should it update to the material specified in the file or do I need to manually adjust this? Also what is the default it reads the dropdown or the information in the file itself?

mBender wrote:

digiex_chris wrote:

tommylight wrote:

Just a stab in the dark, but does the TX0108E have capacitors wired to power lines and close to the chip?
A 10 microFarad electrolytic and a 0.1 micro ceramic should do.
 
 
I'm not as familiar with the TX0108E , but another option is to switch the low side instead of the high side. Such as a simple transistor between the - of the driver and GND, if that's an option for your stepper driver. (See image).

I wonder if you're running into voltage drop on the TX0108E if you're switching the high side? I also wonder if the Tang Nano can't push enough current on the 5v rail for your application, maybe provide an external 5v source to VB? Perhaps monitor VB with the scope as well, see how stable that is?

 

I thought about the Transistor solution as well. I have actually some transistors laying around, but the fact that the new level shifter should arrive any minute has me stopped that. At least for the moment. 

The power supply from the Tang is stable. I had that suspicion too and tested it with my oscilloscope. 5V is clean and no power drop.

What I have found out is that the bidirectional level shifter have some weird logic to figure out which side is driving and it seems they create often problems. I even tried to put the output side with a pull up / pull down. No difference.

I think something like a 74ACT245 where you can external control the direction might be better for this application.
 

On the Tangbob board I use the TXS0108EPW with pull up/down resistors on the input side.

However, to switch optocouplers in the output stages, for example, you still need a driver like the ones installed on the BOB boards (uln2308), the level shifters are not designed for this

digiex_chris wrote:

well, last night I got first movements to work on my iceshield derivative, and got the scale correct. Trying to get my head around the PID settings, I'm a bit lost since I'm normally a stepper guy working with more direct controllers that work similar to parallel port setups, 1 step = 1 step moved, no hunting position. this seems to be treating the fpga as it would treat a servo with encoder feedback. The position doesn't quite reach the commanded position, and it hunts a little, which I find odd for open-loop steppers with no encoder feedback.

Can anyone enlighten me on how to tune this? Is P too high? I have a feeling it maybe should be set to 1.0 instead of the default 250 so there is no gain.
 

the pid-loop is necessary with external hardware, as only velocity information can be sent in this way.

The deviations are actually only rounding errors, which should be no different with mesa hardware.

Remora does it the same way, only with a little trick, there the PID controller is hidden in the driver and linuxcnc does not show the calculated values but those that were sent.

In the beginning I also had the PID controller in the driver (linuxcnc-component), because it was only a copy of the remora driver, but that is actually just optics.

so far, the position has always been accurate to the step...

tuning is also not necessary if you use stepper
 

After I got the error and copied that specific part the error changed it won't come back again.

How would I get an RTAI version of linuxcnc, I have been looking at the getting started and installing linuxcnc and haven't seen anything like that.

I am so confused right now because the documentation has instructions but it seems like packages are missing from the pre-made files, and the documentation that is stated does not work. Then when I go to forums I am being told that some things may be missing. I am so lost right now, I don't know what to follow and what to ignore, out of date info, what files do and don't work with each other...etc.

digiex_chris wrote:

tommylight wrote:

Just a stab in the dark, but does the TX0108E have capacitors wired to power lines and close to the chip?
A 10 microFarad electrolytic and a 0.1 micro ceramic should do.
 
 
I'm not as familiar with the TX0108E , but another option is to switch the low side instead of the high side. Such as a simple transistor between the - of the driver and GND, if that's an option for your stepper driver. (See image).

I wonder if you're running into voltage drop on the TX0108E if you're switching the high side? I also wonder if the Tang Nano can't push enough current on the 5v rail for your application, maybe provide an external 5v source to VB? Perhaps monitor VB with the scope as well, see how stable that is?

 

I thought about the Transistor solution as well. I have actually some transistors laying around, but the fact that the new level shifter should arrive any minute has me stopped that. At least for the moment. 

The power supply from the Tang is stable. I had that suspicion too and tested it with my oscilloscope. 5V is clean and no power drop.

What I have found out is that the bidirectional level shifter have some weird logic to figure out which side is driving and it seems they create often problems. I even tried to put the output side with a pull up / pull down. No difference.

I think something like a 74ACT245 where you can external control the direction might be better for this application.

tommylight wrote:

Just a stab in the dark, but does the TX0108E have capacitors wired to power lines and close to the chip?
A 10 microFarad electrolytic and a 0.1 micro ceramic should do.
 
 

I'm not as familiar with the TX0108E , but another option is to switch the low side instead of the high side. Such as a simple transistor between the - of the driver and GND, if that's an option for your stepper driver. (See image).



I wonder if you're running into voltage drop on the TX0108E if you're switching the high side? I also wonder if the Tang Nano can't push enough current on the 5v rail for your application, maybe provide an external 5v source to VB? Perhaps monitor VB with the scope as well, see how stable that is?
 

is that doing the same thing as the irq coalesce blurb in the network manager setup?

well, last night I got first movements to work on my iceshield derivative, and got the scale correct. Trying to get my head around the PID settings, I'm a bit lost since I'm normally a stepper guy working with more direct controllers that work similar to parallel port setups, 1 step = 1 step moved, no hunting position. this seems to be treating the fpga as it would treat a servo with encoder feedback. The position doesn't quite reach the commanded position, and it hunts a little, which I find odd for open-loop steppers with no encoder feedback.

Can anyone enlighten me on how to tune this? Is P too high? I have a feeling it maybe should be set to 1.0 instead of the default 250 so there is no gain.