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That's actually rather strange behavior and may have to do with
the 7I76E analog output being unsigned.

Can you post your hal/ini files?

I would get open loop working well first with P,I,D == 0
and FF0 = 1, then try to slowly add some P and I

(you will never get good control without FF0)

Also plotting the PID output will help with diagnosis

Hi all, 

Looking for some help with my closed loop spindle. It's a no-name "AT4" chinesium VFD driving a 3kW motor and a 2.2:1 belt drive to a BT30 spindle. Control is 0-5V from a 7i76e, encoder feedback from the motor shaft. The encoder is a 2500ppr unit I had left over so I'm only using the index pulse and have the encoder in counter mode because the A/B pulses were too fast. Encoder feedback into a 7i89.

Anyway, with P only control, I see the motor hunting a lot, a slow oscillation a few hundred rpm triangular wave, but I don't think it's as a result of too high P : there still a significant offset error so the oscillation is maintained even though the error is always a negative value (spindle slower than target). Lowering the P more increases the offset but doesn't change the amplitude or frequency of the oscillation, increasing P moves the speed closer to the setpoint but again no change in the oscillations. No screenshot but I can get one later on. Because it "hunts" even though the error is large and always one side of the setpoint makes me think it's not true hunting like a system with overly high P gain? The oscillation doesn't decay over time.. same behaviour with P anywhere from 0.8 to 10. 

I reduced P way down (to 0.5) and tried to get it working by using D to stop the oscillation and I to actually hit the setpoint, but it's still a bit shit so I think it could be much improved. I added a ramp constraint to the speed command to stop the vfd erroring out. There's an accel limit on the VFD side too so maybe that's affecting the control loop?  

It's getting to it's setpoint now but there's an over-acceleration initially, then a ramp that doesn't quite keep up, and then a weird over/undershoot/dip when the ramp ends and the I term seems to take over to slowly creep the speed to the setpoint. 

Can anyone who knows controls better than me suggest a methodology to follow to improve this?

First Question.

For a 1mm jog, I originally set my MUX40.in1 to 1.0. This was resulting in an exact 4mm jog each count. To fix this I need to set the scale below to 0.25. While I can do this and get the result I want, it bothers me that I have to use a ratio instead of direct number and will be harder to decode at latter dates. It seem arbritary that each count would be 4mm exact.

setp mux4.0.in1 1 (jogs 4 mm per count)

setp mux4.0.in1 0.25 (Jogs 1 mm per count)

net encoder-counts  <= encoder.0.counts
net encoder-counts => axis.x.jog-counts

Question is, where is the actual jog value recorded in LinuxCNC.? I cold find nothing in the .ini or .hal files that seems to indicated it would jog exactly 4mm each jog count.



Second question,

Per the below, I am currently using mux4 to determine the jog scale. But my MPG switch does is not using an encoder switch but instead has 3 simple outputs of which I placed into input 26 (1x), 27(10x), 28(100x)

I got everything to work but can not find any details in .hal how to use something other than mux4 logic to place the correct scale into the axis jog. This seems like it should be simple. More or less just want if one of those pins are true, the correct scale is selected. Below is partial code referancing the scale portion. Note. Only using pins 26 and 27 at the moment due to the mux4 requirements. Other than this, everything is working fine.

# This sets the scale that will be used based on the input to the mux4
setp mux4.0.in0 0.025
setp mux4.0.in1 0.25
setp mux4.0.in2 2.5

# The inputs to the mux4 component
net scale1 mux4.0.sel0 <= hm2_7i76e.0.7i76.0.0.input-26
net scale2 mux4.0.sel1 <= hm2_7i76e.0.7i76.0.0.input-27

# The output from the mux4 is sent to each axis jog scale
net mpg-scale <= mux4.0.out
net mpg-scale => axis.x.jog-scale

---

Basically want:

if Pin 26 true then axis.x.jog-scale == 0.025
if pin 27 true then axis.x.jog-scale == 0.25
if pin 28 true then axis.x.jog-scale == 2.5

Hallo Michael,

Danke für deine Antwort.Ich habe damals(ca.8 Jahren) mit LinuxCNC schon angefangen.Da hatte ich ein TB6560 Board von Modellbau Letmathe.Ich begann mit einen (China)Kreuztisch.Dann baute ich mir eine Portalfräse.Irgendwie bin ich auf den Planetcnc Controller gestossen.Denn habe ich genommen.
Zum Schluß wollte ich wieder umsteigen auf LinuxCNC.Habe mir dann eine MESA 7i76E gekauf und einen VFD mit Spindel.
Dann wurde ich krank und das Geld wurde knapp.Da verkaufte ich die Karte und Spindel wieder.

Jetzt habe ich nur das USB Board,die Motortreiber(Endstufen) und meinen Schaltschrank denn ich damals gebaut habe.
Ich habe sogar einen Pendant gebaut.Als USB HID Device,mit einen Teensy 3.2 und Joystick/Keypad.

Jetzt wollte ich das WHB04-4 Handrad in Planetcnc integrieren.Geht aber irgenwie nicht.Habe die .rules geändert usw. ......

Ich habe mir gedacht,man könnte die 26pin Schnittstelle verwenden.Ohne viel umzuverdrahten.

Hab gleich einen Termin.Melde mich wieder.

Grüße-Martin

---

Hello Michael,

Thanks for your answer.I started with LinuxCNC back then (about 8 years ago).I had a TB6560 board from Modellbau Letmathe.I started with a (China) cross table.then I built myself a portal milling machine.somehow I came across the Planetcnc controller.because I took it.
Finally I wanted to switch back to LinuxCNC and bought a MESA 7i76E and a VFD with spindle.
Then I got sick and ran out of money, so I sold the board and spindle again.

Now I only have the USB board, the motor drivers (power amplifiers) and my control cabinet that I built back then.
I even built a counterpart as a USB HID device with a Teensy 3.2 and joystick/keypad.

Now I wanted to integrate the WHB04-4 handwheel into Planetcnc, but somehow I couldn't. I changed the .rules etc. ......

I thought you could use the 26pin interface without having to rewire much.

I have an appointment in a few minutes.

Greetings-Martin

For configurations with specific daughtercards, the daughtercard 
name is included in the file name and you can use the .pin file
to determine the content and pinout of the firmware, for example
the 7i76eu_7i76x1_pktv2d.pin file shows that the configuration
includes a V2 PktUART ( the TX and RX halves )

7i76eu_7i76x1_pktv2d.bin 

Would be the correct firmware

You will also need to update LinuxCNC to the lastest version
sine the hm2_modbus driver is quite new.

 

thank you.
I know I need to update / flash my 7i76eu.
The "bundle" from your webpage contains 20+ different firmware files... I would assume that 7i76eud.bin/pin are the correct ones, right? (for a standalone 7i76eu without any extensions)

Hello y'all!
I just received my new mesa 7i76eu, and I have a huge CNC with a durapulse GS10 vfd (until now it was runnnig with grblhal).

Does "pktUart" allow me to connect my GS10 vfd directly to the mesa without a usb dongle?

Regards!

Saw this old iron while entertaining the machinery buying itch today on Kijiji -- www.kijiji.ca/v-other-business-industria...i-hit-18s/1716314528

That link will go dead with time, so for the record it looks like a Hyundai HIT 18S for $2k Canadian, not working. Seller says it has some repaired drives. I probably need to ask more questions, just not sure what all the right ones are.

Seller might be asking too much, but says he's open to offers. Any thoughts from more experienced heads here, whether or not something like this is worth a look and a retrofit? Or should I be running the other way fast as I can? I don't have any impressions, good or bad, about Hyundai quality, and I'm not sure what dead machines should generally go for.

On the scale of difficulty for retrofits, where does a machine like this fall? I'm no expert with HAL but have dabbled a little. Built my own plasma table with 7i76e and a couple THCAD's by riding on the shoulders of giants on this forum.

Thanks in advance for any time you spend looking at this.

Hi langdons! Thanks for your question!
Yes the VFD has more than one output. One +24V for maybe switches or relays, two relay outputs and one +10v output that puts voltage to the electronic potentiometer on the 7i76e. The mesa doesn't have such a voltage output on board, so you have to give that from an external source (eg the VFD 10V out) to the spindle+ input. The spindle-output then gives the 0-10V voltage correspondingly to the set rpms back to the VFD's analog input and, if the FWD signal is on, the spindle turns.
In my case, the rpm output voltage AND the spindle.enable = spindle.on signal is only given out from LCNC if I do this from a file. Normally - and any time before, this works even with any MDI speed command.

So - the VFD (now) works as it should but LCNC has problems to give the right MDI Commands as ordered to the outputs of the MESA card.
The VFD had no +10V on its H output as it came to me, from the dealer, new product, no NOS, freshly produced 3 years ago. I wasn't ready to build that thing in because I was busy with the mechanic part of my CNC. I put some parameters in the first weeks, but no real testing with any controller, so I didn't mention that problem. I found that few weeks ago, as I installed the VFD and tried to get the spindle turning. And found that there is no +10V at Out H. Then, the external 10V source, but I wanted the VFD beeing allright, so I sent it to Hitachi for Service.

I wasn't able to go down to my machine the last days, but I will make a video of that process the next days.

Kind regards!

Hi Todd,
I’ve checked everything—the only thing left is the motor encoder, and a lot of people, including an electrician, told me it’s likely the problem. I’ve tested all the cables (several times), the controller, and I’ve even done parameter resets. So, It must be the encoder , because i've powered the motor with a  power supply and it works.Just to clarify: I’m not doing the retrofit only for  the motor. It’s because I’ve been talking to a guy who used to work on the same machine, and he said there are serious issues with the Z axis ,it doesn’t save its position. Actually, before the machine broke, I had experienced this issue myself.Over the last few days, I did some research and found a good shop online Variumetrum and  i have done some research and seem's good so here my choices:

• 3 x Leadshine ELM1 750W with brake
• 3 x Leadshine AC Servodrive EL6 750W
• 1 x Mesa 7I76EU(not from the same shop)

On the old machine i've Sanyo Denki 500W  DC80 Model 850T-0123EL7 , brushed motor .
Let me know what you think!

Ps- I've only to think to the z axis and than i can buy all of them.

Ofcourse! 

I've included them as an attachment.

I hope you have some good insights into my setup. 

Thanks in advance.

EDIT:

I now also use the following step timing:

DIRSETUP   = 500
DIRHOLD    = 500
STEPLEN    = 1000
STEPSPACE  = 1000
STEP_SCALE = 1000

In addition, I changed the |DISPLAY|MAX_VELOCITY and the |TRAJ| VELOCITY settings. I have also increased the other velocity limits accordingly.The machine is now performing better than ever!
Surprisingly, I'm no longer getting any following errors—I'm not entirely sure why, but I’m definitely not complaining. ?Thanks to everyone for the input and suggestions!

Can you post your complete hal/ini files?

Hello Community,
many things are working nowadays with  Linuxcnc 2.9.2 with Probe Basic on a MESA 7i76e. But:

A few weeks ago I had to change my Hitachi VFD because it had no 10V output for spindle supply from the beginning. I sent it to service in April and I had to get the 10V from a separated power supply, this worked fine with a chinese VFD for the time the Hitachi VFD was in service.
Last week the Hitachi came back from service, the 10V Out was working, but surprisingly I cannot make MDI speed commands any more. I set S6000 or S12000, press Enter, in the spindle display on the right side 22000 occurs and I can press FWD Button but nothing happens.
IN the HALSHOW there is
0 at spindle-out
0 at spindle.0.speed.out
0 at spindle.0.on
0 at spindle.0.forward. Tested with S6000, S12000 S24000.

All this worked fine with the chinese VFD before.
So, I thought my 7i76e card is burnt up (I did not change any of my HAL or INI files since I sent my Hitachi away), but surprisingly further experiments could deny that.
Speed instructions from a file are working as they should. E.g. my warmup file - spindle turns in the right direction, right speed, right display down right.
Parameters are the same in the Hitachi as before.

Do you have any idea what could have happened here? I'm totally clueless...
Thanks for any hint and help!

Hanno
HAL and INI Files:
    

Presuming there is nothing wrong with the original servo systems, then usually the best option is to reuse them. You will need to figure out how the existing cnc controlled the servos. If they were using step/dir signals then the 7i76e should be a good option for the retrofit. If the servos were commanded using analog signals or some other way (such as some kind of serial bus), then some other hardware might be more appropriate.