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  • ississ
  • ississ's Avatar
24 May 2024 11:37
Replied by ississ on topic fixing a mess i made, probably...

fixing a mess i made, probably...

Category: General LinuxCNC Questions

Normally transistor E is connected to ground without a resistor when a transistor is used as a switch like here.
Base always need a resistor to limit the base current (otherwise the transistor base may burn. In this case the E-gnd resistor should save the transistor).
Resistor between C and load is needed depending on the load. For example if the transistor or load current should be limited for some reason.

Simplified:
- logic level low on base (via a resistor): Transistor is "off" and current does not flow from C to E. "The switch is open"
- logic level high on base (via a resistor): Transistor is "on" and current flows from C to E. "The switch is closed"

In some cases it's better to place the resistor between E and ground (typically audio circuits etc). When a transistor is used as aswitch E should be at ground and suitable resistor on base.
Base resistor size depends on the transistor and the drive voltage.
Also note that many transistors do not like reverse voltages. So make a simple test circuit and verify that the transistor still works.
  • jerry420
  • jerry420
24 May 2024 11:30
Replied by jerry420 on topic Wrong md5sum leading to failed installation?

Wrong md5sum leading to failed installation?

Category: Installing LinuxCNC

Thanks for the suggestions, will try win32diskimager when I get the new stick.

In the meanwhile I've tried to use the virtual machine, thats a great idea! Should eliminate any chance of the stick being bad. I've seen other forum posts here where a faulty hardware device worked on ubuntu install but not debian, which is why I initially suspect the stick to be bad.

In another forum post (i found out about the search functionality, albeit a bit late) I read that zsync does not take HTTPS, only HTTP, so when trying that I managed to also download the correct ISO version.

I also saw Balena Etcher coming along, might try it too if I don't have any results.

Will revert back once I have results on the VM / new hardware / new ISO / win32diskimager.

Thanks for the tip on Ventoy, I just read their main page, looks very interesting!

 
  • pmchetan
  • pmchetan
24 May 2024 10:36 - 24 May 2024 10:48
Replied by pmchetan on topic fixing a mess i made, probably...

fixing a mess i made, probably...

Category: General LinuxCNC Questions

 

=28pxWorking of BC547 Transistor=20pxWhen the input voltage is applied at the base terminal, then some amount of current starts to flow from the base terminal to the emitter terminal and controls the current at the collector terminal. The voltage between the base terminal and the emitter terminal (V=14pxBE), is negative at the emitter terminal and positive at the base terminal for its NPN construction. The voltage between the collector and the base (V=14pxCB), is negative at the base and positive at the collector terminal and the voltage between the collector and the emitter (V=14pxCE), is negative at the emitter and positive at the collector terminal.

 

  • The base terminal of the transistor is getting the pwm signals from 7i76 step- pin.     
  • I tried with swapping the collector and emitter connections but both gives 0volts against ground.     

The way I understand it the classic transistor operation like a switch:    
The logic high from the pwm signal from 7i76 means current flows through the base terminal, which means the transistor is in forward bias, and the current will be allowed to flow through collector to emitter. When the pwm signal is low, transistor is in reverse bias and some current flows through base terminal to the emitter and the path between collector and the emitter is blocked.    
So if thats how it works, there will be a small current flowing from the base terminal to emitter whenever the PWM signal supplies logic low and since emitter is connected to ground of the drive, that current does nothing and when the PWM signal supplies logic high, there's no current since it just connects the collector to the emitter which are in turn attached to sv and common on the drive.    
What am I missing? how is the pwm signals reaching the drive pins?
  • stonebite
  • stonebite
24 May 2024 10:11
Replied by stonebite on topic PNCconf 7i92H and 7i76

PNCconf 7i92H and 7i76

Category: PnCConf Wizard

now that the ribbon cable is correctly polarized, I have simulated running the machine three times for a longer period of time.
Started the machine and simulated the axes. I then let the machine stand still to see what happens.
The following three errors occurred after each start and referencing of the machine, each time between 10-25 minutes.

 

  • stonebite
  • stonebite
24 May 2024 10:05
Replied by stonebite on topic PNCconf 7i92H and 7i76

PNCconf 7i92H and 7i76

Category: PnCConf Wizard

Again the current Readout
cnc@cnc:~$ ping 10.10.10.10
PING 10.10.10.10 (10.10.10.10) 56(84) bytes of data.
64 bytes from 10.10.10.10: icmp_seq=1 ttl=64 time=0.192 ms
64 bytes from 10.10.10.10: icmp_seq=2 ttl=64 time=0.133 ms
64 bytes from 10.10.10.10: icmp_seq=3 ttl=64 time=0.125 ms
^C
--- 10.10.10.10 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2056ms
rtt min/avg/max/mdev = 0.125/0.150/0.192/0.029 ms
cnc@cnc:~$ ping 10.10.10.11
PING 10.10.10.11 (10.10.10.11) 56(84) bytes of data.
64 bytes from 10.10.10.11: icmp_seq=1 ttl=64 time=0.026 ms
64 bytes from 10.10.10.11: icmp_seq=2 ttl=64 time=0.060 ms
64 bytes from 10.10.10.11: icmp_seq=3 ttl=64 time=0.060 ms
64 bytes from 10.10.10.11: icmp_seq=4 ttl=64 time=0.064 ms
^C
--- 10.10.10.11 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3057ms
rtt min/avg/max/mdev = 0.026/0.052/0.064/0.015 ms
cnc@cnc:~$ sudo mesaflash --device 7i92 --addr 10.10.10.10 --readhmid
[sudo] Passwort für cnc:
Configuration Name: HOSTMOT2

General configuration information:

  BoardName : MESA7I92
  FPGA Size: 9 KGates
  FPGA Pins: 144
  Number of IO Ports: 2
  Width of one I/O port: 17
  Clock Low frequency: 100.0000 MHz
  Clock High frequency: 200.0000 MHz
  IDROM Type: 3
  Instance Stride 0: 4
  Instance Stride 1: 64
  Register Stride 0: 256
  Register Stride 1: 256

Modules in configuration:

  Module: DPLL
  There are 1 of DPLL in configuration
  Version: 0
  Registers: 7
  BaseAddress: 7000
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: WatchDog
  There are 1 of WatchDog in configuration
  Version: 0
  Registers: 3
  BaseAddress: 0C00
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: IOPort
  There are 2 of IOPort in configuration
  Version: 0
  Registers: 5
  BaseAddress: 1000
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: QCount
  There are 2 of QCount in configuration
  Version: 2
  Registers: 5
  BaseAddress: 3000
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: SSerial
  There are 1 of SSerial in configuration
  Version: 0
  Registers: 6
  BaseAddress: 5B00
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 64 bytes

  Module: StepGen
  There are 10 of StepGen in configuration
  Version: 2
  Registers: 10
  BaseAddress: 2000
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: LED
  There are 1 of LED in configuration
  Version: 0
  Registers: 1
  BaseAddress: 0200
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

Configuration pin-out:

IO Connections for P2
DB25 pin#             I/O   Pri. func    Sec. func        Chan     Sec. Pin func   Sec. Pin Dir

 1                      0   IOPort       StepGen          0        Dir/Table2      (Out)
14                      1   IOPort       StepGen          0        Step/Table1     (Out)
 2                      2   IOPort       StepGen          1        Dir/Table2      (Out)
15                      3   IOPort       StepGen          1        Step/Table1     (Out)
 3                      4   IOPort       StepGen          2        Dir/Table2      (Out)
16                      5   IOPort       StepGen          2        Step/Table1     (Out)
 4                      6   IOPort       StepGen          3        Dir/Table2      (Out)
17                      7   IOPort       StepGen          3        Step/Table1     (Out)
 5                      8   IOPort       StepGen          4        Dir/Table2      (Out)
 6                      9   IOPort       StepGen          4        Step/Table1     (Out)
 7                     10   IOPort       SSerial          0        TXData0         (Out)
 8                     11   IOPort       SSerial          0        RXData0         (In)
 9                     12   IOPort       SSerial          0        TXData1         (Out)
10                     13   IOPort       SSerial          0        RXData1         (In)
11                     14   IOPort       QCount           0        Quad-IDX        (In)
12                     15   IOPort       QCount           0        Quad-B          (In)
13                     16   IOPort       QCount           0        Quad-A          (In)

IO Connections for P1
DB25 pin#             I/O   Pri. func    Sec. func        Chan     Sec. Pin func   Sec. Pin Dir

 1                     17   IOPort       StepGen          5        Dir/Table2      (Out)
14                     18   IOPort       StepGen          5        Step/Table1     (Out)
 2                     19   IOPort       StepGen          6        Dir/Table2      (Out)
15                     20   IOPort       StepGen          6        Step/Table1     (Out)
 3                     21   IOPort       StepGen          7        Dir/Table2      (Out)
16                     22   IOPort       StepGen          7        Step/Table1     (Out)
 4                     23   IOPort       StepGen          8        Dir/Table2      (Out)
17                     24   IOPort       StepGen          8        Step/Table1     (Out)
 5                     25   IOPort       StepGen          9        Dir/Table2      (Out)
 6                     26   IOPort       StepGen          9        Step/Table1     (Out)
 7                     27   IOPort       SSerial          0        TXData2         (Out)
 8                     28   IOPort       SSerial          0        RXData2         (In)
 9                     29   IOPort       SSerial          0        TXData3         (Out)
10                     30   IOPort       SSerial          0        RXData3         (In)
11                     31   IOPort       QCount           1        Quad-IDX        (In)
12                     32   IOPort       QCount           1        Quad-B          (In)
13                     33   IOPort       QCount           1        Quad-A          (In)
  • Unlogic
  • Unlogic
24 May 2024 09:46
Replied by Unlogic on topic Preview doesn't match actual program path

Preview doesn't match actual program path

Category: QtPyVCP

Big thanks TurBoss!
  • TurBoss
  • TurBoss's Avatar
24 May 2024 08:12
Replied by TurBoss on topic Preview doesn't match actual program path

Preview doesn't match actual program path

Category: QtPyVCP

Hello,

Finally fixed :-) took me a while, the fixes are now on a test branch they will go main soon


 


Thanks
  • Aciera
  • Aciera's Avatar
24 May 2024 07:50 - 24 May 2024 07:53
Replied by Aciera on topic fixing a mess i made, probably...

fixing a mess i made, probably...

Category: General LinuxCNC Questions

Connecting GND to the Collector and (presumably) SV to the Emitter this doesn't make much sense to me.
If I wanted to invert the PWM signal (presuming that SV is pulled up when open) then I would connect SV by resistor to the Collector and connect the Emitter to GND.
[edit]
So I'd say the 'C' and 'E' markings are wrong as suggested in the previous post.
  • jimmyrig
  • jimmyrig
24 May 2024 07:45
Would anyone be interested in a parallel port to mini driver board was created by jimmyrig

Would anyone be interested in a parallel port to mini driver board

Category: Driver Boards

Would anyone be interested in a parallel port to 3d printer driver board. Thinking of basically copying the cheap CNC BOB but adding the headers for common drivers like a4988, drv8255, tmc2009, etc that way you can just plug it in without wiring drivers. 

Any specific requirements?
Seems like the 5 axis, 5 input, analog out and relay from the BOB would cover most cases. Thinking of copying the CNC BOB pinout exactly so it works with mesa and parallel port configs out of the gate. 

​​​​​
Won't be able to get to it for a bit, just curious if I'm the only one who has wanted one. 



​​​
  • ississ
  • ississ's Avatar
24 May 2024 07:43
Replied by ississ on topic fixing a mess i made, probably...

fixing a mess i made, probably...

Category: General LinuxCNC Questions

"(In the arduino code, I saw analog write function used to write to the pin and got confused with the whole analog pwm thing)"

Simple google with "arduino analogwrite" should help (link to arduino function reference).
Original arduino boards using small avr cpus do not have analog output. So they decided to name the pwm output function analogwrite() and use the resistor-capacitor filter to get analog output from pwm. Resistor and capacitor are not on the arduino board.

Using analogwrite() in arduino code would output pwm square wave which is just what is needed.

I think that the transistor markings are wrong, BC547 is npn so normally E should be connected to ground and C to drive pwm input.

"How is the transistor inverting the signal from active high to active low in this circuit? "
If B & E are swapped in the image, high voltage on base will connect C & B -> transisto pulls sv pin low -> signal from arduino is inverted.

Without proper documentation it's very hard to guess how to connect the drive. One possibility is to open it and try to figure out how the input side is done. I don't recommend that if you are not familiar with that kind of work with electronics.

Some drives does not like 100% pwm. Also check that the switches are set correctly.
  • pavel7890
  • pavel7890
24 May 2024 07:36
Replied by pavel7890 on topic Different acceleration across joints

Different acceleration across joints

Category: Basic Configuration

Some details:
LinuxCNC Version 2.9.2
Rexroth Servos via EtherCat SoE, 1ms servocycle, command position + position feedback
  • jimmyrig
  • jimmyrig
24 May 2024 07:18
Replied by jimmyrig on topic ESP32/S2/S3 LinuxCNC Controller (6 axis hardware step gen), USB plug-and-play

ESP32/S2/S3 LinuxCNC Controller (6 axis hardware step gen), USB plug-and-play

Category: Computers and Hardware

BIGTREETECH Direct Octopus V1.1 Control Board 32Bit Silent Motherboard Support 8 Axis TMC2209 Stepper Motor Driver Compatible BTT PI V1.2/PI 2 to Running Klipper/Marlin for Voron 2.4 CoreXY 3D Printer a.co/d/0etbdjV

AliExpress is usually cheaper.

No kidding on the USB thing, almost had a few burn down cause of it. Put them in a big drywall box for this reason.

I'd love to switch over my 3d printers. Hard to justify when a mesa board costs as much as the printers I buy.... that work just well enough for me to not want to mess with it.


Would love to see input shaping in lcnc. Could turn my CNC plasma accelerations way up. I run a light weight aluminum gantry that's got a bit of vibration at high acceleration. The motors are powerful enough to get the whole 750kg table rocking back and forth when accelerations get high enough. Gantry weighs maybe 10kg.

One of these days I might dig into marlin and see what it would take. Slowly learning lcnc codebase.
  • jjdege
  • jjdege's Avatar
24 May 2024 07:18
Replied by jjdege on topic Help,Leadshine DM556 open-loop stepper config

Help,Leadshine DM556 open-loop stepper config

Category: EtherCAT

in the terminal ,while I used "ethercat sl" command ,it did show up connected to DM3E-556 but while

Connected in "OP" mode or "SAFEOP"?
LCNC starts?
if it starts in halpin lcec.0. your device with connection pins, are they visible?
  • pmchetan
  • pmchetan
24 May 2024 07:05
Replied by pmchetan on topic fixing a mess i made, probably...

fixing a mess i made, probably...

Category: General LinuxCNC Questions

I thought the transistor is there for switching which connects the collector and emitter at the pwm frequency at the base of the transistor. But I think I'm wrong because with PWM mode selected on the drive, it should drive the motor if I supply 5v volts to sv pin (its the same as 100% duty cycle) but it doesn't.
How is the transistor inverting the signal from active high to active low in this circuit?
  • jimmyrig
  • jimmyrig
24 May 2024 06:59
Replied by jimmyrig on topic I need help

I need help

Category: General LinuxCNC Questions

Does your PC boot?
Does your controller turn on?
Can they talk....Can you get any motion at all?
Where is it not working? You said mechanical is ok but nothing about electronics or software.
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