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Author Topic: Panasonic servo drive help  (Read 61026 times)

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Offline rwf71

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Re: Panasonic servo drive help
« Reply #50 on: March 19, 2013, 09:08:31 PM »
Hey Dickeybird,
      I think it was a Zenith,used to lay in front of it watching cartoons when I was a kid. And I didn't cover that stuff, that's my ole lady's quilting machine & frame, she ain't real happy I'm with me in HER space this winter.LOL
      Rick

Offline Hood

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Re: Panasonic servo drive help
« Reply #51 on: March 20, 2013, 03:54:43 AM »
Thank You Hood,
   Hey I have another question, I've been looking over the input cable rework & we determined pins 28,29,30,12&9 should be 0 volts (com-). The wiring diagram I got from seller says 3.5&7  are GND (ground). Here's the question, are ground & 0 vdc (com-) the same thing in this application, I mean can/should I tie these ALL together?
                     Rick
Pins 3, 5 and 7 etc are for the Step/Dir signals and in reality, according to the manual, they should really be the inverse of the signals, ie differential signalling should really be used. Often drives will work fine being connected single ended like that but I always use a line driver to make the step/dir signals differential as it makes them much more immune to noise problems.
 Looking at your BOB I am thinking the 24v and the 5v will be tied together internally, you can probably check with an volt meter between the 24v out and gnd and then also between a Dir pin and that Gnd, if you get 24 and 5v (may have to jog a different dir to get the 5v) then they are tied and not much you can do if you use that BOB.
 Most drives I have seen have separate commons for the stp/dir inputs and the logic power but whether yours do I dont know, easy enough to check with an ohm meter between the commons of each on the drive itself (with no plug connected)
I wouldnt like to say for sure whether it would be a problem or not  if they are isolated but as said if your BOB is not isolated then not much you can do about it.
Hood

Offline rwf71

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Re: Panasonic servo drive help
« Reply #52 on: March 20, 2013, 06:13:24 AM »
OK Hood.
    I think I followed most of that,getting ready for work now,will use VOM to check tonite. I know I have 24 v between gnd & 24v now so if I have 5v between gnd & dir that means they are tied together on the BOB and I could tie gnd & coms together,correct? I also understand you don't like it that way best but I have no choice if I use this BOB.
    Now is where I step wayout of my league, If I understand correctly with this BOB the dir signal will vary from 0 to 5v, but you prefer a line driver (whatever THAT is) because of better noise isolation. Does that mean the dir input receives a wider voltage difference (like 5 to 24v) or just a cleaner 0 to 5v because of the isolation?
     I would like to use this BOB to a least get motors jogging and verify the drives and servo motors are OK but I DON'T want to build a problematic machine susceptible to noise issues, If you think there's a better way to do things now is the time for me to change things but I would need your help to know how & what to change. ::)
     I don't personally know anyone I can talk to that would even have a clue what I'm talking about, let alone answer my questions.Thank you very much for taking your time to help me out Hood, your a gentleman and a scholar!
                          Rick

Offline Hood

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Re: Panasonic servo drive help
« Reply #53 on: March 20, 2013, 02:37:55 PM »
You can actually still use the BOB and not have to connect the 0v to pins 5 and 7, to do that you need to make your step/dir signal into a differential Step/Dir signal. What that would mean is for every positive positive step pulse Mach puts out there would be a negative one, same with Dir signal. So you would have Step + connected to pin 6 and Step - connected to pin 5, Dir + to pin 8 and Dir- to pin 7.

Line drivers can be bought or made, if making them you would need a line driver similar to this
http://uk.rs-online.com/web/p/line-transmitters/0630875/
That is a quad driver which means you can have 2 axis of step/dir signals with it, so 3 axis would require 2 of them.
As said you can buy them ready made, I think US Digital sells them but you would need 1 for  each axis if going that route as their line drivers are meant for fitting to encoders so only have A, B and I channels.

Hood


Re: Panasonic servo drive help
« Reply #54 on: March 20, 2013, 02:46:49 PM »
Here is another line driver that might interest you.
http://www.cnc4pc.com/Store/osc/product_info.php?cPath=64_78&products_id=337
Russ

Offline Hood

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Re: Panasonic servo drive help
« Reply #55 on: March 20, 2013, 04:53:09 PM »
I was going to link to CNCDrives line drivers but thought as they are in Hungary it would probably not be a great source, forgot though that CNC4PC are a stockist for them.
Hood

Offline rwf71

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Re: Panasonic servo drive help
« Reply #56 on: March 20, 2013, 07:56:10 PM »
Hey Hood,
    I did some checking with a VOM on my BOB. Checks were made on the same axis (Z), gnd to 24v =21,3,gnd to dir = 3.3, gnd to clk =3.3, there is a 5v that seller didn't say to use and there I have ; gnd to 5v =5. I was late getting home tonite so haven't looked into the line drivers that were linked yet. At this time I'm not sure what they are or how to use them.
    It does seem gnd & com- are the same on this BOB so all those pins COULD be tied together for a test but is 3.3 V going to be a good enough signal at the dir & clk inputs?
                       Rick

Offline rwf71

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Re: Panasonic servo drive help
« Reply #57 on: March 20, 2013, 08:37:44 PM »
OK guys,
    I checked out the line driver links. Hood, the one you linked looks a little to sophisticated for a non electronics guy like myself and I presume you need a socket for that IC to make connections?
    After looking at the one Overloaded linked (thanks) I think I get the idea & use. I already have some RJ45 modular plugs and the stripping/crimping pliers for them so I have the output end covered and I like the screw terminal inputs. Would it be OK to get the ground & 5 V inputs from the axis outputs on the BOB? BTW those CNC4PC line drivers look pretty small and I didn't see any provision for mounting them, do you just let them "hang" in the wiring or is there a proper mounting method?
                                      Rick
Re: Panasonic servo drive help
« Reply #58 on: March 20, 2013, 09:05:26 PM »
Hi Rick,
  You can connect the wires to the screw terminals, then slip a length of heat shrink tube over the unit extending slightly beyond each end. Trim if necessary for the RJ 45 plug then just let it dangle or tuck it into the ducting.
Russ

Offline rwf71

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Re: Panasonic servo drive help
« Reply #59 on: March 20, 2013, 09:23:24 PM »
OK thanks Russ,
    I would already have them on order but website says they are on backorder,none in stock, not even one for me to try. I emailed them to see if they have an idea when they are getting them, I don't want to "lock in" with an order then find them elsewhere faster.
                   Rick