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  #1  
Old Tue 06 January 2009, 08:23
osman100
Just call me: osman100
 
giza
Egypt
AC motor & VFD used with Mach3 in large CNC stone cutting system

(Have merged 3 threads into 1. Read on - Osman got his system to work!)

i need to buld cnc to cut marble so stepper motor will not enough to laed axies so i'd like to use geared motor with inverter omron f7 which is able to work as steeper but with more power and also i can connect an encoder with it so in this case it will be like a server so can u tell me your suggetion about that
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  #2  
Old Tue 06 January 2009, 09:21
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
The only Omron F7 Inverter that I could find on the Internet is a Variable Frequency Drive (VFD) that would be used to run a three phase motor (spindle).

For a CNC machine you need either stepper motors or servo motors to position the tooling. The VFD is used to run the spindle at a high, constant speed.
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  #3  
Old Tue 06 January 2009, 10:03
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Mike, those VFD's are used for position controlling AC motors as well. Look how well passenger carrying elevators stop at the floors these days - they are using our "common" VFDs. Today's elevators are soo smooooth and sooo precise, irrespective of whether empty or full.
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  #4  
Old Tue 06 January 2009, 10:44
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
I can easily see how that would work with an elevator, even with minimal or no feedback sensors; the number of output cycles from the VFD should map directly to a known position of the elevator, independent of accel, decel, etc. This would allow a "digitally" deterministic system that gets you very close, most of the time, and a little feedback locks you back on, in a rather stepper motor like way.

I can't quite envision how you would ensure accurate, coordinated multi axis movement using several VFDs, unless you added encoders and created PID feedback loops like a servo system. Is there a known technology for synchronizing multiple "common" VFDs "digitally"? This would make the control system somewhat stepper like.

As long as I'm asking silling questions, it's often occurred to me that it should be possible to get the control / feedback required for something like a hard tapping cycle just from the circuits in a VFD, assuming that the internal microprocessor is appropriately programmed. The current feedback sensors from the output phases should tell you what the motor shaft is doing. Is this done, or do we still rely on shaft encoders or something else?

(No, I'm not going to run hard tapping cycles on my MechMate, I'm just curious).
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  #5  
Old Tue 06 January 2009, 10:47
Woodchuck
Just call me: Stew
 
Southeast Iowa
United States of America
Howdy

This is my first post and I don't want to sound like a know it all cause I don't.
As I start a MM build someday I will prove it!
VFD's like Gerald said can be used to position motors, control rpm, torque and
you can input single phase to output 3 phase to run motors. They have
programmable inputs and outputs as well as ramp up and ramp down features
along with many others. The cost is getting reasonable for the average guy to
have them.
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  #6  
Old Tue 06 January 2009, 12:05
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Omron and Yaskawa are the same. Here is something on driving a gantry with two motors to hold it square . . . :

http://www.yaskawa.com/site/dmdrive....L.F7SW.064.pdf

Note the accuracy of one encoder count!
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  #7  
Old Tue 06 January 2009, 12:53
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
That would do it. Run a set of VFDs in "follower" mode without a master, and then feed the quadrature signals from a parallel port, and you've got yourself a system that pretty much looks like stepper drives to Mach3 or EMC.

Thanks for indulging me. Now to find an application for a 3HP stepper motor ... maybe an MM to cut an http://www.icehotel.com/ out of a glacier ;-)
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  #8  
Old Tue 06 January 2009, 17:56
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
I had no idea that a standard VFD had those capabilities. It looks like it's time for me to thoroughly study the VFD manual.

Although I don't see that I would need heavy-duty motors, those that use indexers might find a use for a big controllable motor.
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  #9  
Old Thu 09 April 2009, 05:28
osman100
Just call me: osman100
 
giza
Egypt
Step & direction pulse shapes in Mach3

pls can someone helpe me to know the direction puls shape which come from mach 3 software .
are this is wave puls as a puls train in one direction and no pulse in the other direction or it's like contact between 2 point so that it can used for connect a realy or it's like one puls for certain period 1 micro sec. every change or other ?
if any one help me for this i'll be very glad and thanks him very much
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  #10  
Old Thu 09 April 2009, 06:42
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
The direction signal from Mach 3 is a steady state signal. That means that one direction will be a constant 0-vdc and the other direction will be a constant 5-vdc (actual voltages may be 0.7v and as low as 2.5v).

The only requirement is this (from the G203v manual):

There are no unusual STEP to DIRECTION timing restrictions. Stepping occurs on the positive edge of the STEP pulse. The DIRECTION input must be true 200nS before and after this STEP pulse edge.

Mach 3 handles that timing requirement, so you don't have to worry about it at all. In normal operation, the direction signal is set and then step signals are sent to the stepper driver. Before the next command is executed, if the direction needs to change, the direction signal is set and then the step pulses for that move are sent to the stepper driver.

Last edited by Richards; Thu 09 April 2009 at 06:44..
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  #11  
Old Thu 09 April 2009, 06:57
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
There are two different step/direction methods commonly used. The method that Gecko and Mach 3 use is called Step/Direction. That method sends all step pulses on one signal line and the direction signal on another signal line. The direction signal is either TTL high or TTL low. A TTL high voltage is 2.2V to 5V. A TTL low voltage is 0V to 0.7V.

The other method sends step pulses on one signal line to move the motor CW and then sends step pulses on another signal line to move the motor CCW. This second method is NOT used by Gecko or Mach 3 - at least I haven't read anything in the Mach 3 setup guide about using the second method.

Usually, the stepper driver has opto-isolators on the input lines. That means that the device that sends signals to the stepper driver (the break-out-board) needs to SINK or SOURCE current in order to turn the opto-isolators on. On the Gecko G201 and G202, the Break-out-Board needs to SINK current. On the G203v, the Break-out-board needs to SOURCE current.

From your description, the Omron driver has opto-isolators on it's input lines. If you can post a model number, someone can check the documentation to help you better understand the requirements.
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  #12  
Old Fri 10 April 2009, 06:24
osman100
Just call me: osman100
 
giza
Egypt
dear friends
the type of omron driver is f7 inverter type
thanks a lot
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  #13  
Old Fri 10 April 2009, 06:30
osman100
Just call me: osman100
 
giza
Egypt
the web page of this frequancy inverter (driver) is
http://industrial.omron.eu/en/produc...7/default.html
and the cod is cimr-f7z41p5
with card pg-b2
all the best
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  #14  
Old Fri 10 April 2009, 08:40
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
I assumed that you needed information about sending direction to a stepper driver; however, you need help with a VFD. That is totally different.

Pages 277 and 279 (of the Y203-EN2-02+Motion&Direction+Catalogue pdf file that I downloaded from the website that you posted), shows how to wire the direction signals.

It looks like the VFD has three power connections for the input signals (S1 - S7).

- SP is the 24-VDC power source for the internal opto-isolators.
- SC is the anode connection to all the opto-isolators
- SN is the 0-VDC or Ground connection

Therefore, SP needs to be jumper wired to SC to supply 24v to the opto-isolators.

Each input function (S1 - S7) becomes active (turns on) when it is connected by a switch (relay contacts, contactor contacts, or manual switch contacts, transistor, etc) to the SN terminal. [EDITED: Each contact needs to be able to SINK 8mA at 24V. That is less than 0.2W, so the load is small enough for a small transistor to handle. However, the load is too small to be used with a Solid State Relay. Most Solid State Relays require a much higher load.]

To make the VFD turn the motor in the Forward direction, S1 needs to be connected to SN. To make the VFD turn the spindle in the Revers direction, S2 needs to be connected to SN. BE CAREFUL. If S1 is connected to SN, then S2 needs to be open. If S2 is connected to SN, then S1 needs to be open.

My Delta VFD for my Colombo spindle had to be programmed before the input signals worked properly. I would assume that the Omron VFD has a manual that would tell you how to properly program the unit. I have not even attempted to change the settings recommended by Shopbot for my Delta VFD. There are many, many functions available (and there are many, many ways to mess things up), so I made only the recommended program changes.

Last edited by Richards; Fri 10 April 2009 at 08:54..
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  #15  
Old Fri 10 April 2009, 12:56
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Osman, I am curious why you have a VFD running under the control of Mach3. Which motor/s of your CNC system do you want to drive with the VFD.

Irfan
We have 3 different types of Delta VFD's and two different types of spindle, with 2 different types of power supply (single & 3 phase). There are differences in the settings for all of them. It takes a couple of minutes with a clear head to run through the manual and pick the settings you need. 90% of the options are not needed for a simple spindle application.
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  #16  
Old Sat 11 April 2009, 08:10
osman100
Just call me: osman100
 
giza
Egypt
dear all friends
actually i have a bridge cutter to cutt a marble and granits it's look like a milling machine and i'd like to make some modefication on it to work as cnc for cutting and engraving marbles but it move to 3 axies direction by 3 phase ac motor but this machine need a power when cutting so stepper motor is not enough and servo will be very expensive so i studies to make it work by this type of inverter which is have a facelity to make ac mortor work as servo with feedback from the encoder which fixed on the motor but this need an optional card pg-b2 which will be fixed inside the inverter and also the inverter take the pulses from mach 3 pins as afreq refrance to adjust the steps and i'm already sucsseed in this step but when i trided to take a direction signal to change the motor direction i'm not sucsseed i take this signal to 5 volt relay to connect s1 or s2 to sn contact in the inverter according to direction of movment and this also help me to contact only one of it (s1,s2) not both of it but i found the inverter not change the direction so this things make me aske about the shape of direction signl in mach 3
also in this inverter also i can program it through contact s5 to work as 3-wire connection so the direction will be change acoording the contact between s5 and sn if it open one direcion and if it close the other direction
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  #17  
Old Sat 11 April 2009, 10:52
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Mike & Irfan, I split this thread and moved the Delta stuff to here:
Programming Delta VFD's for spindle motors
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  #18  
Old Sun 12 April 2009, 06:25
osman100
Just call me: osman100
 
giza
Egypt
i'm in need to use direction puls to drive a relay 5 volt but when i checked voltage between pin 3 and pin 18 i found it 3.5 volt and when i conect it to the 5 volt relay it's droped to 1.5 and in the other direction it will be 2.1 milli volt what can i do to solve this problem pls
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  #19  
Old Sun 12 April 2009, 08:34
jhiggins7
Just call me: John #26
 
Hebron, Ohio
United States of America
Osman,

I'm assuming that you're talking about the "direction signal" from the PMDX-122.

If so, as you've already discovered, those signals are not strong enough to drive a relay. Also, if you connect a relay to PIN 3, you won't be able to drive any other device (too much drain). You need an auxiliary circuit to "boost" the signal that doesn't "load" the signal too much.

I used Fig. B from this web page to build a relay board to drive Contactor relays. I used 3 Fig. B circuits. I connected the inputs to transistors to PIN 14, 16 and 17 and ground to the GND pin of J8. I connected the +V to the + 5V AUX OUT of J8. Works fine.

If the no load voltage of the PMDX-122 PIN3 is 3.5 volts, as you've indicated, you'll probably need to use a circuit like Fig A., rather than Fig B.

If you decide to build one of these circuits, I can tell you the parts that I used. I haven't built and tested a Fig. A circuit, so beware if you plan to build and test that circuit. I bread-boarded and tested my version of Fig. B before building the Relay Board.

Regards,
John
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  #20  
Old Sun 12 April 2009, 10:12
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
John, that is a link to a file on your PC - it is not a www address.
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  #21  
Old Sun 12 April 2009, 10:33
jhiggins7
Just call me: John #26
 
Hebron, Ohio
United States of America
Thanks Gerald.

Here's the Internet link for circuits to control relays.

Regards,
John
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  #22  
Old Sun 12 April 2009, 10:45
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Osman, what was the resistance (ohms) in the coil of the relay that you tried? Maybe this one will work:
http://eg.rs-online.com/web/search/s...hTerm=480-0797
It is from RS-online in Egypt.

Max voltage allowed 4.5V, normal voltage 3V, will switch at 2.2V, only needs 180 mWatt power. (coil resistance 100 milliOhm)
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  #23  
Old Sun 12 April 2009, 12:56
osman100
Just call me: osman100
 
giza
Egypt
dear jhiggins7 and Gerald
thanks alo i hink this which i'm need bu i'll test tomorow then i'll keep in touch then i'll tell both of yours about the resualt
best regards
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  #24  
Old Mon 13 April 2009, 06:10
osman100
Just call me: osman100
 
giza
Egypt
dear friend thanks a lot i already test fig b with transistor and it work well
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  #25  
Old Mon 13 April 2009, 07:34
jhiggins7
Just call me: John #26
 
Hebron, Ohio
United States of America
Osman,

Great news! Glad it worked for you.

Good luck with your build.

Regards,
John
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  #26  
Old Mon 13 April 2009, 10:59
osman100
Just call me: osman100
 
giza
Egypt
dear John
thanks
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  #27  
Old Mon 13 April 2009, 11:08
osman100
Just call me: osman100
 
giza
Egypt
AC motor & VFD used with Mach3 in large CNC system

with mach 3 according to manual i use the following program to check the step error
F1000 (i.e. faster than possible but Mach3 will limit speed)
G20 G90 (Inch and Absolute)
M98 P1234 L50 (run subroutine 50 times)
M30 (stop)
O1234
G1 X4
G1 X0 (do a feed rate move and move back)
M99 (return)
but after finishing it i found it not go back to the same start position
can u help me to solve this problem
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  #28  
Old Mon 13 April 2009, 11:36
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
osman,

Check your pinon gear set screws to see if they are tight. Is there any play when you turn the pinon gear? That might be a cause of your problem.
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  #29  
Old Mon 13 April 2009, 13:33
mphel
Just call me: Mark
 
Upton upon Severn
United Kingdom
Osman,
Try adding % to the end of the file:-

F1000 (i.e. faster than possible but Mach3 will limit speed)
G20 G90 (Inch and Absolute)
M98 P1234 L50 (run subroutine 50 times)
M30 (stop)
O1234
G1 X4
G1 X0 (do a feed rate move and move back)
M99 (return)
%
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  #30  
Old Mon 13 April 2009, 13:58
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Osman's system is not a standard CNC router. See Step & direction pulse shapes in Mach3

Osman, that relay might be too slow. Maybe you can reduce the Acceleration setting in Mach's motor tuning?

Or you can think of putting a delay into the program before a reversal in direction (to force the motion to stop while the relay is changing).
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