Topics

1

Modbus / Lag between Mach3 and ModIO output turning on

« on: May 16, 2014, 05:43:18 AM »

Hey Everybody, got a problem that may or may not have a fix. Hoping there is one.

We have a CNC-controlled painting machine that turns on and off 50 pumps (different colors of paint) using outputs from Homann Designs' ModIO. We have 7 ModIOs connected together to get this many outputs. We've got the system working by issuing VB commands to turn on/off OEM Leds which are then read by a brain to set the corresponding output in the ModIO. (Buffer times are set for 25ms in the Modbus config page)

Problem: There is a 0.5 second lag (roughly) between the issuing of the macro command to turn on the pump and the moment when the pump actually turns on (or off). Also, it seems the lag is different for different boards (further down the chain the delay seems to be slightly longer).

Does anyone know whether this is an issue that we can fix or do we just have to try to work around this lag using dwell times and design changes?

Thanks!
Sam

2

G-Code, CAD, and CAM discussions / How do I do an XY axis tool offset rather than a Z?

« on: May 15, 2014, 05:49:27 AM »

We are building a modified CNC machine that will drip a stream of paint instead of turning a spindle. The way the machine is built the table moves and the paint heads are stationary. The paint heads will be laid out in several rows together and there will be 50 of them. (See attached picture for an illustration)

My Question: When we switch from one paint head to the next, how would you recommend doing this "tool change" in the G-code?

A normal tool change would account for a Z axis tool offset. In this case all of our paint heads are the same Z position (stationary), but the X and Y positions are different for each. Should I handle this as a tool change? Or write a custom macro? Or should I just write Gcode to move at relative coordinates to the new tool position?

Would love to hear from some voices of experience before starting down one of these roads!

3

Modbus / Problem with Test Modbus Function

« on: May 01, 2014, 09:03:08 PM »

Hey Everyone, I'm running into a strange problem with the ModIO. I originally hooked it up following the manual and the Test Modbus function worked perfectly. Later I accidentally tripped an error on the board I was using and switched it out for a new board (haven't had time to go back and fix the original). Since then, I haven't been able to get Test Modbus working correctly.

I think my settings are the same as before, but now it will connect with "No Error" when I open the port, but will read "Receive Timeout" if I try to read/write to any registers. What makes it even stranger is that I can set registers fine using a brain.

Even stranger is that if I choose a register to read, say 103 for example, it first says "Receive Timeout" but if I click the Decimal radio button it will read out the data in decimal. Then if I click the Hex radio button it will read it out the values in Hex. 

The whole reason I'm messing with this in the first place is to set the 103 register to FF in order to keep the output lights 1-4 from blinking. However I haven't been able to write to the registers because of the above reasons. Any help you can give would be appreciated!

Attached is a screenshot of the settings I'm using. This is what it looks like after I've clicked Decimal and then Hex. But there's still a "Receive Timeout" on the bottom.

Thanks,
Sam

4

Modbus / How to Address Modbus Outputs if you have more than 20

« on: April 19, 2014, 09:58:25 AM »

Hi everyone, we are building a machine that needs 50 discrete outputs. We are planning to daisy chain 7 of Peter Homann's ModIO boards together. I have been able to use a brain to assign Mach3 Outputs to the ModIO output holding registers. So far so good.

The problem is that I can only find 20 outputs within Mach3. So I can set the first 20 outputs using brains, but I don't know how to address outputs 21-50.

My idea was to use custom M codes which would map to VB scripts as in this post: http://www.machsupport.com/forum/index.php?topic=15179.0.

That will work great for the first 20, but anyone have any ideas how to set the rest?

5

Modbus / Best way to get extra outputs

« on: April 08, 2014, 01:40:08 AM »

We are building a modified CNC machine that sprays paint instead of running a cutting blade. Because of this we need about 50 outputs to control different colors of paint. Can anyone recommend hardware (breakout boards, PLCs, modbus) which could do this? If I understand correctly, Mach 3 can support up to 63 outputs, right?

We have purchased the Homann ModIO, and I am aware that we can buy several of these and link them together to achieve our result. It would be great if we could do it in one unit though.

I'm a newcomer to CNC, so sorry if this is an obvious question.