Messages

161

General Mach Discussion / Re: AutoZero Plate for Z Axis

« on: March 05, 2011, 08:16:51 AM »

Kolias:
Tweakie is correct. I got onto a bit of a tangent trying to figure out what you have there.  As I also mentioned I don't think it's going to work having the plate and your limits on the same input anyway, so while you're playing with wiring you might as well start now to re-wire things to free up an input.

 Having said that you still need to understand the way the switches are actually wired and the mach settings to fully undestand the ACTIVE LOW or ACTIVE HIGH logic.
 It may be that the BOB is inverting the sense of the actual switch action making it necessary to set the reverse logic in the software.  (is that possible ??) This will make it doubly confusing.

Sage

162

General Mach Discussion / Re: AutoZero Plate for Z Axis

« on: March 04, 2011, 11:56:51 PM »

I'll think about it some more in my sleep.
Active LOW means that the LIMIT condition will be triggered when Mach sees a LOW (ground) on the input (i.e. the condition is ACTIVE when the signal goes LOW)
  It baffles me how this is working now if ,as you say, you have NC switches. If this is ture then all the inputs are LOW already and that should be triggering all the limits. The lights would be on for them in the diagnostics screen.
 Are you sure these are not NO switches. You can test this by pulling the wires off of one of the switches and use an ohmmeter across the connection on the switch from where the wires came. If you measure a short (0 ohms) then you are correct. If there is an open circuit (no meter reaction) then they are in fact NO.

Let me think on it. There is no need to use more than one input for all of the limits and even the home switches, freeing up a lot of inputs. What you do is wire them all in series.

From the BOB input to a switch, from that switch, to the next switch, from that switch to the next etc. etc and finally back to ground on the BOB. The switches have to be all N.C. so the signal can be activated by any one of the switches going open. The setting would be set for ACTIVE HIGH. (the SIGNAL is normally low and is ACTIVATED when it goes HIGH). The high comes from the pull up resistor when the line is no longer pulled low by the switch string.

Sage

163

General Mach Discussion / Re: AutoZero Plate for Z Axis

« on: March 04, 2011, 10:32:48 PM »

Take the rest of the night. Not sure where you are but I'm going to bed.

While your at it make a drawing of what you have for the limits. Where the wire starts, check the status of the switch (NO or NC) and where it goes to and any other details.
If you have a meter measure the voltage to ground on the limit switch wire when it's sitting idle (switches NOT activated).

Later

Sage

164

General Mach Discussion / Re: AutoZero Plate for Z Axis

« on: March 04, 2011, 10:15:45 PM »

Can you trace and describe the wiring of your limit switches. I can't see how you can have NC switches AND have active LOW.

Usually you would have NO switches, the input would be pulled high by the resistor and the switch when activated would close and pull the input LOW (to ground).

Are you using an input for each limit? (because you can hook them all together on one input and free up at least 2 inputs).

You are not understanding what I mean about the limts and the zero setter being used at the same time.
The two are in conflict. The way you plan to use them they are ONE IN THE SAME. If you are using the zero setter and the clip touches the plate then you are triggering LIMIT and ZERO at the same time. Mach may pay attention to the LIMIT condition and shut down any further movement of the Z-axis and cancel or at best screw up your zero setting.
Get the idea??

165

General Mach Discussion / Re: AutoZero Plate for Z Axis

« on: March 04, 2011, 09:44:58 PM »

BTW.
I'm not sure using the same inputs as the limits is going to work in any case. I'm not sure if the limits have priority over the Zero setting code. If the tool zero and a limit are triggered at the same time (since they are the same in your wiring) which one wins?  Perhaps the limits are not payed any attention while the VB code is running I don't know.
 At best this would be a race condition. Sometihng best avoided. Is there another input you could use. Perhaps a home switch input.

Ps> It was Tweakie that posted some VB code for you Not Hood. Sorry.

Sage
 

166

General Mach Discussion / Re: AutoZero Plate for Z Axis

« on: March 04, 2011, 09:28:54 PM »

Re-read my previouis post for more information. I was editing more into it when you posted.

What could possibly be wrong with an aluminum plate pray-tell??  

Are your limit switches N.O. or Normally closed? It could be they are normally closed and pulling the input low (shorted to ground). Have a look at the activation state of the limit switches in the software. If they are set to active HIGH then they are normally closed switches and are pulling the input to ground. If so you won't be able to use that input (unless you re-wire the limits).
 You should also be able to see the light go on and off when you activate the limits.

The VB code in your doc file looks too simple to do the job, but I'm no expert. Try the one Hodd posted and/or the one I linked to.

If the light works on the limit switches then try running the VB code and trigger one of your limits instead of using the plate and clip. This will tell you if the code is reading the input properly.

Sage

167

General Mach Discussion / Re: AutoZero Plate for Z Axis

« on: March 04, 2011, 09:01:24 PM »

Kolias:
Take Ger21's advice and don't run the VB code any more until you get the input working. You're just asking for a broken tool or machine damage.

Simply put , the light should be normally off and if you touch the clip lead to the plate you should see the light go on. It should be off otherwise.

Did you install the pull-up resistor between pin10 (or whatever your using) and 5v?
Some BOB's need this resistor. The resistor should be something like 1k.

With the resistor in place you have a setup for active LOW to trigger the input. Make the settings in the software to match active LOW. If making and breaking the connection between the clip and the plate has no effect after that then something is not working with the input you are using. Please report your findings.


BTW you can't use the bare aluminum plate on the metal table or piece of work in the milling machine. Usually the plate is a piece of PC board (copper plate insulated from the table or work). The aluminum plate would be ok for a router I guess where you are always placing it on wood.


When you get that working you should get the code from CNC zone forum subject "aussie tool setter" where it was developed. Here is a link to some code. http://www.cnczone.com/forums/cnc_wood_router_project_log/36099-another_aussie_auto_tool_zero-35.html
You'll need to enter the thickness of your plate in inches. The code is metric. It's well described where to make the change.

168

Newfangled Solutions Mach3 Wizards / Re: Surface Material Wizard - bug - odd values

« on: February 20, 2011, 08:34:22 PM »

I'm not surprised. Sheetcam does it that way as well and it's a pretty smart program.

I was thinking about this some more and there is another reason the last past should never be over the requested amount:

The last past doesn't even need to be calculated. It can just be a copy of the value of the requested finished depth.
The intermediate passes can be calculated (like they are) but the last calculation can be scrapped in favour of just subbing in the requested depth value. Done - no error.

I guess that's a happy compromise.

So - Ron - Can you make it do that??
At least the final extra tenth (or any other rounding error produced) will be gone and won't ned to be explained.

Sage

169

Newfangled Solutions Mach3 Wizards / Re: Surface Material Wizard - bug - odd values

« on: February 19, 2011, 09:25:32 PM »

3 thou isn't a rub. It's a fairly typical finish pass.
Having said that the subtraction method could result in some pretty small final passes. None the less it seems to be the way it's accomplished in other programs - not my doing.

Actually the wizzard does have an error, it's one tenth. That's a lot in some circles.. (certainly not mine). Zero error would be better and could be accomplished with only bit more code to make the final pass exactly correct since we already know what the final dimension should be. (Rather than leave it to the operator to figure it out and edit the G-code). If I can figure it out then the wizzard should be able to as well.

I guess we can agree to disagree.

Sage

170

Newfangled Solutions Mach3 Wizards / Re: Surface Material Wizard - bug - odd values

« on: February 19, 2011, 07:11:52 PM »

Don't be too quick to make excuses for the wizard.
There shouldn't be any round off error and there was no need for it to select three screwey sized cuts causing the problem.
It's pretty simple. I spec'd a cut of .010 and a depth of .020 - two cuts of .010 no remainder.

Normally - from what I've seen from other wizards and other programs like sheetcam etc. - the program just keeps taking cuts as specified and any remainder is left for the final cut. Never any error that way and it's just simple subtraction.

e.g assume depth specified as  .023 and depth of cut .010
Take cuts of .010+.010 and a final cut of .003 - voila exactly .023 no tricky division required.
That's the way I've always seen it done.

I'm really surprised such a simple wizzard has errors. I wouldn't normally use such a simple wizzard except I was showing someone what Mach could do with wizzards and this came up - sort of embarassing actually.

Sage