Messages

1

Show"N"Tell ( What you have made with your CNC machine.) / Re: Isolation Routing PCB's and Local System Rotate.

« on: June 21, 2013, 09:48:13 PM »

You certainly can.
The camera plugin (I use WebCamPlugin version 2.12) runs in a separate window and has cross hairs in the center.
All you need to do is centre the start point in the camera view by jogging the mill and the either note down the DRO numbers or zero them. Then jog the mill to the next point and read the DRO's.
You get the X and Y distance. If you want the straight line distance when X and Y both change then you just need to use Pythagoras triangle theory to calculate that distance.

The closer the camera is to the surface the better accuracy you will get.

2

Finished Plugins for Download / Re: Huanyang VFD controller plugin

« on: May 02, 2011, 09:02:27 PM »

Hi RT,
The MAX485 chip looks like it will do the job. PC1 and PC2 are part of the motor drive circuit, you will need to get some chips that are the same as PC3 through to PC6.
I would class it as unfit for its intended service with out them because they are essential components.
It might be worth checking to see if the hassle and cost of getting a replacement VFD is worth it, or just getting the parts and having a friend or local electronics repair shop put them in for you.
You can always have a go at installing them yourself if you like. Sounds like you got one that was assembled a day or two before Chinese New Year.

Cheers,
Phil

3

Brains Development / Re: Out-put control word to sequential range of coils (Danfoss VFD)

« on: April 26, 2011, 09:27:01 AM »

Thanks Scott,
I'll report back with what I end up using. A bit more research on Mach variables to do and then hit the issue head on.
Thanks for the pointers.
Cheers,
Phil

4

Brains Development / Out-put control word to sequential range of coils (Danfoss VFD)

« on: April 22, 2011, 07:48:53 AM »

HI Guys,
Iv'e watched the tutorials and read the Popper Bears brain guide but I still can't work out how to send to or read from multiple coils (16) in a brain.
It's got to be something easy that I am missing.

My Danfoss VFD has the control bits in coils 0-15 and the spindle speed setting bits in coils 16-31 (speed range 0h - 4000h). Coils 32-47 are the VFD status bits and then coils 48-63 are the spindle speed feed back bits.
Words are sent LSB first

I can control and read from the VFD in the Modbus test screen. The VFD can be stopped by addressing just one bit in the control word but will not start using that method. I have to write to the full 16 coils of the control word.
Each coil only accepts a 0 or 1. 

I imagine the value in the brain would be a decimal representation of the binary word, but I don't know how to break that up for sending to the individual coils in one action.

Any pointers on reading 16 consecutive coils and processing them as a 16bit word, and/or sending a 16bit word to 16 coils?

Cheers,
Phil

Setup Images

5

Finished Plugins for Download / Re: Huanyang VFD controller plugin

« on: April 10, 2011, 07:43:36 AM »

G'day L,
Yep you can decrease the braking time even without a resistor or associated circuitry. It you go too far the VFD will just let go of controlling the spindle speed until the DC bus voltage level drops again. You can hear when this happens.
If you increase the acceleration too much it will just tell you with an over current warning on ramp-up. Should be no risk of damage, just back off the settings until everything is happy again.

On a sadder note, my VFD has fallen to the fabled over-voltage error on startup . Ran great for a 3hr operation but powering up after a 3 day layover I get the error.
When I reset to defaults, my max current is set to 1.5amps and the error still remains.
I'm working on the issue now, and as a true glutton for punishment I'll fork out another $150 for a new one and have a unit I can compare voltages with. I think it will be a hardware fault, well see. If not, I hope they didn't lock the code on the processor, I may be able to read the from good and transfer to the bad.

I won't bother fitting the braking circuitry to the new one, I don't think it is worth it.

Just a quick note. This braking set-up has nothing to do with DC braking. It can be confusing. DC braking is a voltage applied to the motor when it is stopped or very nearly so to hold the motor in one position. ie not able to turn.
If you do that for too long the motor will generate a lot of heat.

Cheers,
Phil

6

General Mach Discussion / Re: Possible to keep limits enabled during home?

« on: April 06, 2011, 11:02:19 PM »

There is a deeper issue than just how the home switch is set up.
The underlying issue is that the limit switches are not active (disregarded) during a home operation.
Just having the home on a cam setup will not sort out issues like a damaged home cable or inoperative switch. If this happens and your setup is active high your axis will sail on past your home position and your limits
I run an active low setup, if the cable is cut then it will be as if the home or limit switch is active. Even with this set up and I get a cut cable then following the logic or the home sequence reversing direction to look for the change of the Home switch from active to idle the axis will just travel full length and sail on past the other end limit because it is disregarded.

Like I said, the issue is not the home switch set up but the fact that the limits are disregarded during a home operation.
This OEM Trigger set up gets around that limitation for those that run separate limit switches from their home switches.

I have no issue with those that run limits and homes on the same input or that Mach is set up to enable that type of system.

That's enough from me now. The OEM setup has been outlined for those who wish to do it, and the reasons behind the requirement to do so are (I think) clear.
Regards,
Phil

7

General Mach Discussion / Re: Possible to keep limits enabled during home?

« on: April 06, 2011, 06:53:19 PM »

Hi kf2qd,
Your right, you should not be able to drive past a limit but the issue arises because during Mach's home sequence the limit signals are disregarded as limits even though I have them on different input pins from the home switches.
This whole issue only arises in a Home routine. Any other time the limits are detected as limits.

For the people that use a limit switch input for homing this is not a problem, their limit is being detected as a home location.
I have separate inputs for all my home and limits switches. I use hall effect sensors for the switches and run an active low system.
My home location on the X axis is 20mm inside my limit location. The X axis is the only axis I have ever had trouble with. Even with mechanical switches you would still have a dead space between the two locations.

LIMIT----HOME-------------------------------------------------------------------------------------------LIMIT

If in the unlikely event I start a home sequence inside that 20mm space, then the home location is on the wrong side of the movement direction. Because of the Mach Home sequence the limits are disabled as limits and the machine will drive past the physical limit location looking for a home input.

Hope this clears it up.
Cheers,
Phil

The reason for the OEM trigger set up is to effectively keep the limits enabled through a Home sequence so you cant drive passed them.

8

General Mach Discussion / Re: Possible to keep limits enabled during home?

« on: April 06, 2011, 10:09:02 AM »

Russ,
You'll be pleased to know that your suggestion worked like a charm, and with a bit more playing around I got it working better than I had hoped.

When I set up the OEM trigger input and disabled the limit input on the X axis, it stopped as expected during a home or jog. But because I have safe Z enabled the Z axis moved to safe Z height as soon as the X axis stopped. No big deal, but scarred the crap out of me the fist time it happened.

I then had the Idea to re-enable the limit input.
Now when the X axis is homing and starts on the wrong side of the home location, the axis gets the stop command from the OEM trigger when it hits the limit switch. The home routine then terminates and the still triggered limit is detected. The system does an E-stop like normal

Way cool, Now I don't have to do any hardware mods.


I'll run through the whole process just in case someone want's to do the same.
You will need to repeat this for each limit that you want active during HOME using a different OEM trigger input.

I went to Config / Ports & Pins / Input Signals and took note of the appropriate limit Port # and Pin number as well as if it was active low or not. I made no changes to this line and left this limit enabled
I duplicated the set up for that limit in the OEM trig #1 line which you will find if you scroll down a bit.
I then clicked OK.
From there I went to Config / System Hotkeys and entered the OEM code of 1003 in the External Buttons - OEM codes section in box 1. This replaced the -1
I clicked OK and that was it.


Thanks Again Russ and Hood for all your help.
Cheers,
Phil

9

Finished Plugins for Download / Re: Huanyang VFD controller plugin

« on: April 04, 2011, 11:31:37 AM »

Hi Sebba,
Sorry I didn't get back to you, I've been a bit busy and sick at the same time.
You might want to check out this thread that I came across tonight.
http://www.machsupport.com/forum/index.php/topic,17192.0.html
It deals with controlling a VFD through Modbus and Brains. I thinks it will be what you are looking for.

Mark,
The braking does work but not as I expected it to.
 
I have a Danfoss VFD on my Bridgeport and with the brake resistor enabled it improves the deceleration considerably from the moment it starts slowing down.

With the brake resistor enabled on the Huanyang and the deceleration time set to the minimum 0.1sec (calculated from 50Hz I think) the slow down rate is not a whole lot different to NOT having it enabled.
The resistor is not used to dump energy until the bus voltage exceeds the max of about 375VDC (don't quote me on that but it's close) which is in the last 10% or so of wind down.
The deceleration time from 24000 rpm (400hz) with a 6mm end mill in the collet is around 5 seconds. Nothing like the setting of 0.8 seconds that the setting implies. 

So with the deceleration set to 0.1sec and the resistor NOT plugged in, the VFD lets go of the spindle (coast stop) when the bus voltage gets too high in that last 10%.
With the resistor plugged in you do get an increased deceleration over normal but only in that last 10% and only till the bus voltage drops below the maximum again.

In summary,
I think that my 2.2kw high speed spindle does not have enough inertia to make any use of the breaking function with an external resistor attached.
You can reduce the deceleration time and get some improvement of deceleration without a resistor. If you drop it too much and the bus voltage goes too high the VFD will just disconnect from the spindle until the bus voltage drops again. (as it should)

If I used the Huanyang on the Bridgeport with it's increased inertia it may work as expected, but that is 380V 3 phase and the Huanyang is only 240V rated.

Cheers,
Phil

10

General Mach Discussion / Re: Possible to keep limits enabled during home?

« on: April 04, 2011, 10:10:38 AM »

Phil, Hood,
  Could you just use OEM Triggers for the limits that are near the home pos. ?
Assign OEM Trigger 1003 (STOP) to those three inputs. Tried 1021 (RESET) but it never goes into EStop.
Seems to work OK here in sim. and allows all jogging afterwards.
Just a thought,
Russ

Thanks for the Idea Russ,
I'll give it a try when I get back to the mill tomorrow night and let you know how it went.

I home at 20% and the limit stays active for about 3mm before the magnet travels too far past.

Cheers,
Phil