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Hi All, 
The ohmic enable gets randomly triggered when laser is enabled. The wiring is as follows to the 7c81 board: 5v from bob , signal to 7c81 encoder pin direct, pins 3 and 4 to gnd of bob. Please help!

hitchhiker wrote:

Warum brauch ich für die 7c81 ein usb-blaster?
Kann man nicht mit dem w5500 modul zugreifen und per mesaflash flashen per ethernet?
 

weil das ganze mesa zeugs nur mit der mesa gateware läuft, also auch das mesaflash,
du könntest noch rio darüber drauf flashen aber danach nicht mehr.
Flashen über Ethernet/SPI ist in rio nicht eingebaut.

@ bladekel:
i take look later

Warum brauch ich für die 7c81 ein usb-blaster?
Kann man nicht mit dem w5500 modul zugreifen und per mesaflash flashen per ethernet?

generell finde ich es pratischer die konfiguration am pc zu machen (VM mit Linux geht auch), dann könnte man auch den TangNano9k programmieren.

Für das ECP5 board brauch man den programmer (usb-blaster, der funktioniert auch am PI und die toolchan auch (arm64) )

Zum betrieb am RPI4 kann man SPI (Jumperwire kabel) nutzen oder en W5500 Ethernet-Adapter (~4-5Euro).

Dann musst du aber noch schauen was du ansteuern möchtest, also z.B. Stepper,
da wird es mit den dev-boards etwas umständlich.

Wie soll denn dein test-aufbau aussehen ?

Oder wenn du eine 7c81hast kannst du die auch nutzen, brauchst aber wie einen PC/VM + USB-Blaster zum programmieren.

Ahaaa i have laying a 7c81... i use on my rpi4 a 7i92.

Other question

What is the cheapest fpga with which i can start? Can you recommand...

Ach qas laber ich hier auf englisch...
Was ist deiner meinung nach der günstigste fpga zum starten?
Stm32 black und bluepill hab ich... auch n radpberry pico usw..

Danke dir

short version:

i put the ethernet cable in the rj45 socket

longer version:
i used the rio gateware and add an w5500 ethernet board to the spi pins:

 

Could you please explain how you connect the 7c81 via ethernet?

Hi All

Thanks for the help with this. But I am truly stuck up in calculation of the below.: 22900 and 23900 & 930000.0
 If the head is away I am getting a safe value of about 24000 for capacitive-sense-velocity in the halshow
My hm2_7c81.0.encoder.00.velocity-rpm is about 1440000 in the halshow.

When i run my program, the IHS happens perfectly but when the the THC takes control the torch just gets the down signal and never goes up. Kindly help with any formulas with these three parameters. Thanks!

# Configure a limit component for the capacitive sensor output since it is scaled
loadrt limit1
addf limit1.0 servo-thread
net capacitive-sense-velocity limit1.0.in
setp limit1.0.min 22900
setp limit1.0.max 23900
# hook up the limited signal to the plasmac arc voltage
net plasmac:arc-voltage-in <= limit1.0.out

and 

# Make a fake Ohmic probe based on the capacitive sensor
# Use the .velocity-rpm so the .velocity can be left unused for arc_ok
loadrt comp count=1
addf comp.0 servo-thread
net fake-ohmic-probe-in hm2_7c81.0.encoder.00.velocity-rpm comp.0.in0
setp comp.0.in1 930000.0
net plasmac:ohmic-probe comp.0.out
# ohmic output is comp.0.out



 

That looks OK but unless the low level signal is < 0.8V it cannot work.

That is, this is a hardware/interfacing issue.

The 7C81 inputs are fine with 5V signals but 1.8V is an indeterminate level
for the TTL level signals that the 7C81 expects

Do you have a data sheet for the encoder?


 

When I have time I will write up a "5aBOB for Dummies". My big router will use a 7c81 x 5aBOB.

Hi
Wiring looks ok to me. Please guide for the below points if they can help
a. Should I decrease the input voltage to 3 V. Will that help?
b. Should I decrease the output voltage of the encoder using a divider?
c. Perhaps changing the below values?
setp    hm2_7c81.0.encoder.00.counter-mode 1
setp    hm2_7c81.0.encoder.00.filter 0
setp    hm2_7c81.0.encoder.00.index-invert 0
setp    hm2_7c81.0.encoder.00.index-mask 0
setp    hm2_7c81.0.encoder.00.index-mask-invert 0

A 1.8V low level is not valid for a 5V single ended encoder output
Maximum low level for TTL signals is 0.8V

This may be a wiring error or similar.

As suggested ,have linked pin to my 7c81 input. Its a single phase encoder. I have set the counter mode to 1. But the values are coming between 1.8v and 5v on my meter. The rawcounts are changing to 1 and then 0. Please help as the encoder is not reading any counts and not changing at all.

I was suggesting wiring the encoder directly to the 7C81 pins
on a different 7C81 connector than the BOB.

(with series 100 Ohm resistors for protection from negative voltage spikes)

Thanks for your reply. But the cheap Chinese boards require 24v power supply to energize its inputs. So inputs are all not responding to 5v input of the encoder. Kindly help as how to wire the 5v inputs with 7c81.