Servo processor "upgrade module" - looking for volonteers.

[kreutz]

So watcha up to?

John Dammeyer

My business is related to the "high end" medical imaging equipment field (X-ray, CT, MRI, Nuclear medicine, PACS, etc) specifically multi-vendor (G.E., Siemens, Philips, etc) equipment sales, technical training (for field engineers) and service.

[tenmetalman]

H.O. & all

with Henrik's help I've been making some progress on my mill. I did have two axis running (X & Y) last week using the uhu chip. I've had a reoccurring problem with poor/no communication between the axes & mach3 and or erratic movement under the terminal program over the life of the project. Henrik gave me some suggestions & using his guidance I got the X & Y axes working well in mach3/uhu chip. I was working in the Z axis & managed to short out the Y drive killing it.....
so after repairing two drives over the weekend I was in the shop today and now have the X & Z axes up and some sort of problem with the Y axis wanting to run away. When I quit to grab a bite to eat I had decided I needed to check my Y encoder cable to see if I've broke a wire or shorted two or more at the drive end (quite a sharp bend there)
I've had the X & Y running using the module and basically just got them rough tuned using the module (before I smoked the Y axis). I had the road runner program running in mach3 and so far what I'm seeing is two significant differences between the uhu & modules. first & what I was hoping for, the module handles 500, 1000 & 2000 count X 4 encoders w/4000rpm servos with no problem, very consistent control . what I wasn't expecting but am pleasantly pleased with is that with the module the servos sound so smooth & as though they are effortlessly going through the motion. when using the uhu chip I thought the servos sounded very good. with the module, the servos have a real different, quiet, free (?) sense about them. I know I'm being very subjective in this post but just wanted to share my experiences so far.
"I'll be back"
Paul

[LZ1TWB]

Hi Paul,

You say motion has different sound, to say better. Is this with the PP or you are using a smooth stepper? I thought once that the irregular sound, going through different speeds was related to mach3's output pulsing and not the drive itself.

Here it makes a lot of difference when using the multiplier option. It gets quite noisy when going to the higher numbers. Of course "0" is the best, but not good for a PP setup with high resolutions.

Todor

[H.O]

Hi Paul,
I'm glad you're on the right track, sorry about the Y-drive though. Like a said in our e-mail conversation I admire your persistance.

What Todor says about the multiplier is true for the new module as well. The higher multiplier setting you use the more the motor will sound as it in reallity are moving in larger "steps" than with a lower multiplier.

Using a higher resolution encoder and then "wasting" that resolution by using the step-multiplier may seem a bit counter productive but in reallity the higher resolution encoder provides more "information" for the servo-loop to work with so it can provide a stiffer control of the motor.

I had a filter routine working earlier that made running with high(ish) step-multilplier settings a lot smoother with the drawback of introducing a slight "lag" to the response but that is not availble in the current firmware.

Regarding the Y-axis, a bad encoder connection can cause runaway, so can a shorted output transistor. Hopefullt it's the former in this case. Let us know how you get on, let me know if there's anything you need.

Thanks for the feedback, I appreciate it!
/Henrik.

[tenmetalman]

Henrik,
as you stated earlier I seem to be one hell of a trouble magnet ! sense I last e-mailed you I managed to take a lightening strike while working on my mill. It killed my mill PC, blew a fuse on my second power supply, & damaged one of the modules you sent me. I have a old slow (1.3Ghz) PC that I've loaded XP & Mach3 on but have had to slow Mach3 down to 25000 vis 45000 where I was running. I have all three axes running, Z using a Uri chip & Y & Z using your modules. I'm rapiding at 45 inches & feeding at 25 inches to keep the computer from locking up while ghosting through the roadrunner program. I'll now go back to interfacing the spindle drive into mach3.... I'd like to send the damaged module back to you for repairs if thats OK. My X axis has always wanted to be jerky at any feed rate above ............ 10 inches or so & working under the module & 25 inches it's smooth as silk. in another e-mail I'd like to send the module settings I'm using, describe the pluses & minuses of the servo performance & see what you suggest. I'll get off my rump & order a motherboard & CPU that run in the 2.7/3 Ghz range & assemble it in the mean time
Awaiting your reply
Paul

[tenmetalman]

Henrik,
sense writing the above post last night I added a M47 to the end of the roadrunner program & let the mill loop through the program for well over a hour.
it preformed without complaint till I needed to go to bed before I fell off my stool.
to answer a earlier question on the list, I'm not using a smoothstepper. I've screwed up so many pieces of hardware I just didn't want to add a additional piece to the mix. as Henrik has pointed out to me I've brought allot of problems on myself by just scabbing things together in the past. sense Henrik has taken me under his wing I've spent hours cleaning up & cutting old wiring out my electrical cabinet. somewhere along the line I'd gotten terribly lazy & having developed bad back problems three years ago didn't help. so anyway the message is do it right or not at all.......
I also had to replace the spindle controller shortly after I got my mill home, had this point, maybe 4 plus years ago. I got the new phase converter up & running the spindle & unhooked it while I sorted out my drive/servo problems. today I plan to put the power back to the spindle, work out the control issues so that the analog spindle control segment on my C-11 BOB controls the spindle within Mach3.
Henrik,
I have modules #011, 012 & 013. I'll double check this morning but I believe it was #013 that the lightening messed up. it still indicates that when powered up all is well via the led & will talk to Hyperterminal. when I command a axis move in either direction (on whatever drive I plug it into) it seems to accept the first movement command. (axis does not actually move) if a second movement command is sent it faults out. I do my posting on Fridays & will package the damaged module & ship it then.
Paul

[H.O]

Hi Paul,

the message is do it right or not at all.......

Yeah, I tried to dress it as much as I could but apparently you read thru the lines and got the message ;-)

Seriously though, with the kind of trouble you've been having with hardware not only working properly but actually breaking, resulting in you having to throw more money on it's better to take a step back and sort one thing out at a time - properly. I'm glad it's all starting to come together for you although I'm sure my part in it is miniscule.

Weird problem with that damaged module...If there's been an overvoltage condition on the suply rail I would expect it to be dead, simply. Anyway, I'll have a look at it when it comes back, in the meantime I'll send you another as a replacement.

If you want me to take a look at your settings go ahead and post them. If you've managed to capture a move with the data recorder you can post that as well - it will give some insight to how the PID is operating. As always, let me know if there's anything I can do to help.

Thanks!
/Henrik.

Oh, you'll HAVE to post a picture or two of the machine and your setup, please!

[tenmetalman]

H.O. & all,
the silence on my end is due to my upstairs heatpump quiting over the weekend.
it's taken me a couple of days to figure out the problem, find out that I had to order parts from California (the other side of the nation, naturally !) & get them ordered this afternoon.
I'd been working on getting Mach3 to control the start/stop, direction & speed of the spindle using the analog 0/10vdc speed controller on my CNC4PC BOB. per the directions I'm using a optical voltage isolator to power the speed control. I'm using a NOS phase converter which that was made in Korea which probably isn't helping figuring out the interface. Mach3 thinks it's controlling the spindle but so far no go ! that's where I'm at..................... I'll be back with the the current settings I'm using with H.O.'s modules & a update on the spindle situation shortly
Paul
BTW, the new motherboard, a FOXCONN A74MK-L. the CPU a AMD Sempron 2.7Ghz single core processor arrived today. I assembled them, added 2 gig of ddr2 800MHz memory & will put it in the case shortly. I'm waiting on the Parallel card, a PCI Express x1 which still is in-route. the above is the core for the replacement PC for the mill controller.

[H.O]

Hi Paul,
Thing do tend to get in the way don't they ;-)

As for the spindle, eariler I sent you a schematic of how I have my C11 wiried, you can see how I did it there and perhaps get some pointers. You mention an optical voltage isolator to power the speed control, do you mean the isolator that is already ON the C11 board or do you have another one in the mix?

/Henrik.

[tenmetalman]

H.O.
see below, I messed this post up !

[tenmetalman]

H.O. ( I didn't think about the list reformatting all my numbers SORRY)
the replacement module arrived today. looks safe & sound. with everything else I've had going on your other module didn't leave here until yesterday ! In answer to your question I put a 12vdc to 12vdc isolator between the 2nd pc power supply I'm using and the analog spindle controller............ I've not spent much time in the shop sense my last post. I did go out there & write down the setting I'm using for the axes modules & Uli chip.
X axis
Module #00012
K= 159 (0)
I= 2 (0)
D=15900 (0)
T=1
V= 0
A= 0
X= 1
L= 6
E= 50000
C= 760
F= 0
O= 0
Y= 2.5MHz
J= 2
K= 0
Peak error (abs) 0

Steps per
31425.21
Velocity
42.102
Accel.
11.1932

Y axis
module #00011
K= 159 (0)
I= 2 (0)
D=15900 (0)
T=1
V= 0
A= 0
X= 1
L= 6
E= 50000
C= 760
F= 0
O= 0
Y= 2.5MHz
J= 2
K= 0
Peak error (abs) 1

Steps per
25240.96386
Velocity
33.696
Accel.
11.1932

Z axis
Uli chip #?
P= 1425
I= O
D= 250
H= 14250
X= 250
T= 255
I= 106
E= 30000
M= 1
Y= 70
0= 362
steps per
9000

All of the steps are rough settings using Mach3 & measuring with a pointer in the spindle to a machinist's rule so I'm sure their off by .070" or so in 5"

Step & Direction Pulse
2 & 2 All axes
this morning I was looking at any & all information trying to get a handle on the wiring & settings required between my VFD, the BOB & analog speed controller. If you look on the CNC4PC site at his C6 variable speed controller & then at the "Sample wiring of a C6 to a WF250Y Inverter" that's what I'm trying to sort out. In addition all of the VFD settings are setable ( if thats a word) I'm going out to the shop a give it another try using this information as a loose guide. "I'll be back" begining to sound like a threat Yet ;^O

[H.O]

Hi Paul,
First, regarding your settings. As long as it works to your liking there really are no wrong settings but here are a couple of things I noted.

You have the (K) parameter set to 0. What this means is that when the motor is within the number of encoder count specified by (J), (2 in in your case) the P, I & D gains are reduced to 0 with similar results to simply disconnecting the motor from the drive. When the error is becomes larger than 2 counts the gains are bumped up to the original values again.

If this IS indeed what you want then it's OK but I sugest you set to 256 to begin with. If you experience vibrations/dithering when the motor is stationary you can try lower this value in steps. The values displayed within paranthesis after P, I & D are the "scaled" values applied when the motor is within the number of counts specified by the (J) parameter.

(The (K)-parameter should default to 256, please double check that on the new module when you power it up).

Setting (E) to any value above 32767 (you have 50000) disables the following error trip limit meaning it will never fault no matter how far off target the motor is. I don't think this is what you want.

Apart from that and as long as it moves smoothly and positions correct I don't have any objections - although (I) seems pretty low.

If you command a long move at say 1/4 of full speed and then use GE a couple of times as it is moving it will show you how much it lags during the move. You could then try to add a little velocity feedforward (V-parameter) and see if you can get the "lag" reduced.

As for your spindle drive I'm afraid I can't be of much assistance without having the docs for your drive. I don't know how the C6 compares to the C11 (you are using the speed control built in to the C11 aren't you?).

/Henrik.