Hello Guest it is July 18, 2019, 04:12:30 PM

Author Topic: Panasonic servo drive help  (Read 61047 times)

0 Members and 1 Guest are viewing this topic.

Offline rwf71

*
  •  126 126
    • View Profile
Re: Panasonic servo drive help
« Reply #160 on: April 16, 2013, 06:16:11 PM »
Hello Gentlemen,
    The few things I read about optocouplers seemed they were in dip packages so I was hoping it might be in a socket where I could lift one out and press a fresh one in, shoulda known it wouldn't be that easy. ::) Even without a socket I could desolder and resolder a new one if through the board. I've never messed with anything surface mount and from what I've read they are VERY tough for a rube like me to deal with, especially the first time or 3. :o Heck,I wouldn't even know what I was looking for, kinda hoping for a dip, google the part#, then hope I was messing with the correct one. ::)
     For now I think I'll try to get the other axis wired and see if I can get a relay to work properly in an alarm state and then maybe come back and try to repair this first one that doesn't seem to work anymore. Still trying to fool myself into thinking that my used drive must have been bad BEFORE I got it. ::) If I did make a mistake (kinda looks like it but I'm still in denial), I'd really not like to do it again. So I wanna understand how you knew this was a sinking output. On page 18 of manual I see a symbol that looks like a coil with a snubber diode connected to pin 26, did you know by the way the diode is biased? Or was it because the coil connection opposite the drive ties into Vdc. Maybe both are clues? I want to make sure I can read this right so I don't screw up again,(some more ;D).

      Thanks for trying to get this through my thick head, Rick

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Panasonic servo drive help
« Reply #161 on: April 16, 2013, 06:32:56 PM »
Well the big clue is it shows the positive 24v (or 12 or whatever you have for the i/o logic) going into the Output and it shows internally that it passes to 0v side. The diode also shows the correct way for that configuration.
Hood
Re: Panasonic servo drive help
« Reply #162 on: April 16, 2013, 06:43:31 PM »
This is about the most basic explanation I've seen.
http://support.motioneng.com/hardware/io/slice-io/topic_sink_source.htm
Russ

Offline rwf71

*
  •  126 126
    • View Profile
Re: Panasonic servo drive help
« Reply #163 on: April 16, 2013, 08:03:39 PM »
Thanks guys,
    I think I got it now. I checked your link Russ, Basic is what I needed. You suggested checking pin 27 for servo ready, which if I got it now means I want to hook up my relay 24v to pin 27, and relay should energize when servo isn't alarmed and denergize when drive has a alarm.
    And if I REALLY am getting it couldn't I use this output for the "trigger" for my proposed "safety circuit"? I did plan to have the relay only operate when drive was alarmed, but would it hurt to always have the relay on until a alarm and then turn off? I could run the Mach 3 e-stop circuit through a set of n.o. contacts on the relay and accomplish the same goal I had in the first place without having to repair the alarm out? Sounds good  as long as there isn't a problem to have a relay on pretty much all the time the drive is powered.
   So what do you men think?

                         Rick
Re: Panasonic servo drive help
« Reply #164 on: April 16, 2013, 09:30:09 PM »
That might just work ... you'd have to verify that it does in fact toggle when alarmed.
Might be a valid work around.
Hopefully, the other drive will work normally so you can verify for sure.
I'd also wait for Hood's confirmation on the proposal.
Quite intuitive thinking though.
Curious,
Russ

edited for spelling
« Last Edit: April 16, 2013, 09:44:43 PM by Overloaded »

Offline rwf71

*
  •  126 126
    • View Profile
Re: Panasonic servo drive help
« Reply #165 on: April 24, 2013, 02:43:11 AM »
    Well, my cnc project has been on the backburner for a few days. We are having a very wet cold spring in my part of the world, came home from work a week ago to find a large tree on my property that is very close to the street leaning at about a 20 to 30 degree angle over the road! :o Ground to wet to hold it up. I called a couple tree guys with bucket trucks about having it taken down, they were busy, can't get here for a few days. When I get up next morning it's raining hard and the tree is down completely blocking the street. :'( Had to take the day off work to play chainsaw in the rain all day clearing the road. Then spending all my free time cleaning up and removing the mess, cleaning the property in general in prep for first mowing of the year which by now was overdue thanks to a wet, cold spring. I got most of the tree removed now and the first mowing is done, still lots of rain and cold, many area roads closed due to flooding. I'm less than 1/2 mile from the Mississippi river but thankfully on high ground, many friends and neighbors not so lucky, lots of sandbagging and levee watching going on here now. :(  
    I have managed to get the  safety relay board built and bench tested, seems to work as I planned on the bench so now I'm working on getting it installed in the system. I added a couple LED's and a switch to the relay board, green led when no alarms, red led when any of the alarm receiving relay's are energized. When an alarm relay is energized it opens the Mach 3 E-stop circuit and activates the "inhibit" to all drives to bring things to a stop. I added a switch that when on lets the board monitor the system and stop all motion in the event of an alarm, but switching off completes the Mach e-stop circuit and re-enables the drives so all axis's but the one with an alarm can be moved in manual for diagnostic and repair purposes.  
    That's how I think things should work and so far it looks like the board I built should give me the features and functions I wanted. I might not have needed the red led because if the green is off and a drive has an alarm the problem is obvious, but if things stop moving and I don't have a drive alarm the red led should tell me if the board I built is the problem. ::)
    Wish me luck, I'll post a pic if and when I get it installed and working,  
                             Rick

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Panasonic servo drive help
« Reply #166 on: April 24, 2013, 03:05:46 AM »
Sounds like you are having fun, not only with the chainsaws but also electronics ;D
Weather has been the same here, hopefully things will improve.
Hood

Offline rwf71

*
  •  126 126
    • View Profile
Re: Panasonic servo drive help
« Reply #167 on: April 28, 2013, 03:21:10 AM »
Project update;
    Well,  I put some more time into this project today, wish I could say this was a progress report but my latest results don't feel like progress. :-\ I made up the 2nd servo drive I/O cable (Y axis), installed it and my "servo drive watchdog" alarm monitor board. When I fired things up for a test the first thing I find is the alarm out from pin 26 works opposite from expected, the circuit is completed when drive is NOT alarmed and open when alarmed. This is how I (we) thought the servo on from pin 27 would work, I still haven't done any testing of pin 27 to know for sure how it works but I did carefully continuity test the cable before install so I'm positive I'm taking the output from pin 26 and NOT 27. With the output from pin 26 working opposite of expected this means my "servo drive watchdog" has the Mach3 e-stop circuit open and the inhibits activated to the drives when there are no servo alarms. This condition did allow me to test the over ride switch on the watchdog board, when I flipped the switch off I could reset Mach3 and jog the X & Y axis (the two that I have I/O cables installed on so far). When I disconnect the encoder cable on Y servo motor the Y drive alarms "22" and the watchdog goes to what should be it's normal run state. So I had to remove the pin 26 wire from the watchdog to get the green LED and be able to jog both X & Y.
    So now I have a X drive where output from pin 26 does nothing and on the Y drive it works backward of what was expected, ain't that a kick in the butt! At this point I'm going to make the Z I/O cable to see what results I get from it before a rework of the watchdog board.
    I only had 3 drives but hope to have a 4th axis someday, and a spare drive for parts/repair would be nice to have. So with that in mind I picked up a couple more drives on ebay this week for what I think is a good price. When they get here I'll have 5 Panasonic drives of the same model, I've put so much time into trying to figure out how the first 3 work I figured I'd stick with the same drives. ::)

    I know this post is long winded as usual but I have another confusion to ask about. Now that I have 2 axises that I can jog I notice something else I don't understand. When I only had the X to jog I noticed it wasn't turning very fast but figured it had to do with motor tuning. Now that I can jog the Y axis I see it turns faster than X. The parameters in both drives are the same, everything in the Mach motor tuning is the same for both axises, and I have run the drive self tuning routine for both axises. I don't understand why the motor jog speed isn't the same when EVERYTHING about both axises is the same? Also when I was in Mach3 >config >motor tuning,  I found the up/down arrow keys would jog both X or Y depending on which tuning page I had up, is that normal?

           Sorry about the long post but I'm confused again (some more ?)
                                   Rick

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Panasonic servo drive help
« Reply #168 on: April 28, 2013, 04:40:49 AM »
Ok on the relay board you made, should just be a simple case of changing from NC contact to NO contact.

Check that you do not have any electronic gearing set in the drives, its sometimes called that and sometimes something else, maybe gear ratio. Basically wha it is, you can set up say 2:1 or 10:1 or whatever and when the drive sees one pulse from the computer it multiplies it by the amount set in the gearing, so in the case of 10:1 you would get the equivalent of 10 pulses worth of motion.

That is normal for motor tuning, you use the Up/Down arrows irrespective of which axis you are testing.

For a servo you should know two things in Motor Tuning, you should know the steps per unit as that is derived from the encoder count x 4 (divided by any electronic gearing) and multiplied  by your screws TPI (if using Imperial which I presume you are) . Say for example your encoders are 2500 count and you dont have any electronic gearing and your screws are 5 turns per inch, that would mean 2500 x 4 = 10,000 multiplied  by 5 = 50,000 steps per inch. This may be problematic if you are using the parallel port as it can only puslse so fast, so say at 25KHz kernel the max velocity you could get would be 25,000/50,000 x 60 = 30 IPM, at 45KHz kernel it would be 54 IPM
 This is where you can use electronic gearing in the drives, that would mean if you had 10:1 set in the drives the steps per unit would be 10 times smaller and thus your velocity could be 10 times greater for a given kernel in Mach. Personally not a huge fan of electronic gearing but if using the parallel port then likely you wont have much coice.

Ok so the other thing you know about a servo system is the max velocity you can achieve, this is because you know the max continuos rating of the motors, so just divide that rpm by the turns per inch of your screws and you have the velocity. That of course is assuming the kernel will allow you to set that.

Hood
« Last Edit: April 28, 2013, 04:42:23 AM by Hood »

Offline rwf71

*
  •  126 126
    • View Profile
Re: Panasonic servo drive help
« Reply #169 on: April 28, 2013, 02:14:15 PM »
Thank You Hood for continuing to reply to my questions and problems, I REALLY DO APPRECIATE IT!
    I will definitely be referring back to your last post when I get a machine finished to hook these motors to in reference to the math and methods of calibration and motor tuning. But for now what had me baffled was I knew all parameters are the same on all drives and when I looked on the Mach motor tuning pages everything was identical as well from axis to axis but the motors were jogging at different speeds. ??? Just for the heck of it I changed the "steps per" field on the Mach3 motor tuning pages, they were all at 2000 when motors were jogging at different RPM's, I changed them to 3000 and now the motors are jogging at exactly the same RPM. ;D I still don't know why they were acting different at 2000 but changing and saving at 3000 seems to have them responding the same and also quite a bit faster RPM. :D
    And of course you are correct about changing the contact configuration of the "Watchdog" relays to get the board to work as I want, (believe it or not I knew that), but it just gripes me to have to keep doing things 2 or 3 times to get them right :-[
    Well I'm off to work on the Z axis I/O cable, when finished I hope to see all 3 axises jog for the first time. Wish me luck, I don't seem to be having much GOOD luck the first time around on this project thus far! ::)

                           Thanks, Rick