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Thread: connecting ac drive to computer

  1. #1
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    Default connecting ac drive to computer

    I am at a standstill. I can figure out how to connect the ac drive to the BOB to run off Mach 3. Here is my post on the 'other' board.

    http://www.practicalmachinist.com/vb...ic-189468.html

    It shows the terminal strip. The link in the post shows the manual. It is too much for me to do I think. It talks about comunication ports or something. Is there a simple way to connect the drive to the bob?

    Here is a suggestion from JST on the prac. board.,..

    "If you have a computer sitting there, and no interface, you will either have to get an interface and suitable device driver, or use the RS422/485 connection, which is a serial communication system similar to the connection to your printer etc. I'd suggest RS485, it is very standard."

    I may have to dump this drive and get an simpler one but thought I would ask here to see if there is a way. Thanks as always! Jim

    Here is the manual.. link...
    http://www.scribd.com/doc/19347162/O...MV-User-Manual

  2. #2
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    Have you looked at the installation/setup documentation and/or asked your question at www.machsupport.com ?
    ----------
    Try to make a living, not a killing. -- Utah Phillips
    Don't believe everything you know. -- Bumper sticker
    Everybody is ignorant, only on different subjects. -- Will Rogers
    There are lots of people who mistake their imagination for their memory. - Josh Billings
    Law of Logical Argument - Anything is possible if you don't know what you are talking about.

  3. #3
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    To hook a VFD to a computer you need a step/dir or pwm to analog interface. Serial RS-422 interfaces will not work with Mach3.

    My favorites are made by Peter Homann:

    http://homanndesigns.com/store/index...products_id=39

    That one will do. I would get the version with the built in DC/Dc converter.

    Set up Step and Direction lines from the computer to the board. Configure Mach as in the instructions. The analog output of the board goes to FR (+) and FC (-), the built in relay go to S1 (Relay NC) S2 (Relay NO) and SC goes to relay common.

    Drive should be set to NPN inputs as in the manual. #2 on the SW2 dip switch should be set to voltage input.

    Set parameter n001 to 10, this should set it to 2 wire mode. Set Parameter n004 to 2, this makes it accept a 0-10v analog signal to control the motor.

    Set the rest of the parameters to match your motor.

  4. #4
    Join Date
    Dec 2005
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    In your drive manual, look up pulse follower mode..

    it is a 5 volt pulse train that dictates speed to inverter.

    Sorry, am about half blind tonight or I'd read the other post.. if you have tried this? well there is always a summer.. it takes pulses and makes a 0-5 volt output. I did have several of these gadgets laying about, look like a relay, but have some kinda amplifier in them.


    Ohh.. 90% time of the drives come, the com port is not there.. ok? they all have computers, cpu's in them.. but no real way or program written inside them to LOOK OUTSIDE for communications.. the lil cpu runs comparisons and checks waveforms, a lot of math. and Stopping once a cycle to "time" a communication from outside disrupts the loops.. Mostly the comm hardware that is not there is a buffer area where the com is stored till the computer complete's a cycle..
    Talking to them lil basic stamps years ago? well.. you'd have to smack it, get it's attention.. I used a pin interupt, but then the program that is running would cease till the communication was over..

    ABB, well they came up with a machine builders dream.. a data highway board where you could just link the drives together and read-dump information into them from a serial cable. Saved about a dozen wires on each drive to connect, and had options like current monitoring from control room and speed, and fault.. all kinda neato things besides just on and off... THEY are high dollar and mostly out of ur price range. Just wiring up a console, instead of thousands of terminations and drilling and installing buttons and switches, meters.. just program them into a d-tam.. off and away.. changes? sit in a nice air conditioned office instead of standing on your head in a console with hot wires all around you to bump or knock loose.
    Last edited by Dawai; 10-01-2009 at 04:35 AM.
    Excuse me, I farted.

  5. #5
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    Most all drives will take an analog voltage input to set speed. That is what the manual potentiometer does, but the voltage can be from any source that will produce one within the range. Usually there are parameters to set the input range and type of signal.

    The most common may be 0 to 10V, but -10 to +10V, and the "4 to 20 ma" type signal are often also allowed

    The pulses mentioned may refer to a "PWM" signal which sets the voltage (and speed) by controlling the width of pulses. it amounts to the same thing as an analog voltage input.

    Many drives have provision for a serial link also. The most common hardware type is RS485, but the "protocol", or structure of the data , may be very specific to the manufacturer.

    The question is how to link up the specific machine control (in your case mach 3) to the drive. Most likely some sort of adapter is required, unless the program runs on special purpose hardware that already has an analog output, for instance.

    Changing drives is not necessarily going to make a difference. The drives market is competitive, and most drives will do what the other drives all do, and have similar inputs. They all try to get installed in place of another manufacturer, which means they have to do what the other guys did, at least.

    Drives are almost a commodity, and most interfaces are going to fit the lowest common demominator.

    A manufacturer may ADD a useful type of input, but it is rare to find a drive that lacks inputs that the other drives in it's "class" have. Any manufacturer that does that without a much lower cost, will not get installed much. But any one that can get it's "special" input used, may be able to "lock out" all the others. Eventually that input will be copied, if it is useful.

    So a different drive won't be likely to offer a magic solution. The manual might be better, though.

  6. #6
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    Apr 2003
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    Good news! Bro inlaw is an electrical engineer.Currently laid off. Gave him a call and he is coming to take a look at what I have.

    Happy dance ~`~`~

  7. #7
    Join Date
    Mar 2006
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    Smile

    I use one of these spindle speed controllers along with mach3 and my VFD.
    http://www.cnc4pc.com/Store/osc/prod...products_id=58

    At the bottom of that page are several easy to understand wiring diagrams for various systems.

    I'm a real knuckle head when it comes to electronics, but I found hooking this setup very easy with the provided fine instructions.
    Steve

  8. #8
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    4-20 ma is the most common feed back loop control out there. You can find plenty of I/O combination boards out there that will interface just fine with Mach3 systems and your drive

  9. #9
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    thanks for all your help guys!

  10. #10
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    4-20ma is common but for motor drives 0-10v is the most common, though this drive the OP has will do 0-10v, 4-20ma, and 0-20ma. I dont think I have ever seen a VFD that has -10-0-+10 input though.

    Omron VFDs and Servos are usually Relabeled Yaskawa Drives. Good drives.

    I really recommend the Homann Designs one. It has LED feedback so you know whats going on. It really helps troubleshooting. Plus the guy has really helped me out with things in the past like my tool changer on the Hercus.

    One thing that you can do when you get the spindle controlled by Mach is to add a spindle sensor and you can close the loop. That is Mach will monitor the speed of the spindle and if is sees it slow down it will kick up the drive to compensate. I have this on my milling machine and it really comes in handy when you get a decent load on the machine, especially at lower RPMs.

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