Messages

261

SmoothStepper USB / Re: SmoothStepper Modbus RPM DRO conflict

« on: January 11, 2011, 06:00:36 PM »

Allow me to expand on this thought a bit as I think it is an important point. If you are threading or doing any other movements that are synchronized to the spindle speed than the index signal MUST go through the SmoothStepper. Since the SmoothStepper is the motion controller it has to synchronize the step pulses with the index pulse, the only way that will work is if the SS receives the index pulse directly.

Yes, this is correct if you are wanting to thread, but this is not the case here, there is no index sensor involved.

The VFD provides the spindle speed via modbus, which is far more convenient that adding a spindle index sensor and feeding it into the Smooth Stepper. The Smooth Stepper plugin should know that no index sensor has been configured and therefore not write to the spindle RPM variable.

I presume that this is now what the fixed plugin is doing.

Cheers,

Peter

262

General Mach Discussion / Re: MPG problems

« on: January 11, 2011, 06:23:19 AM »

Hi,

Check that you do not have any other signals assigned to the same pins used by that encoder.

Cheers,

Peter.

263

General Mach Discussion / Re: Heads up on CADCAM offer from Dolphin UK

« on: December 23, 2010, 08:36:40 PM »

Dave,

It's right there on the home page.

http://www.dolphincadcam.com/

http://www.zen188344.zen.co.uk/download/Hobby%20offer%20Nov%202010-4.pdf

I gave in and bought the lathe module and dongle.

Cheers,

Peter

264

Modbus / Re: Hitachi X200

« on: December 21, 2010, 05:43:13 PM »

Greg,

In addition to the 2 data wires, you also need a 0V line between the X200 and converter.

Cheers,

Peter.

265

Modbus / Re: Hitachi X200

« on: December 21, 2010, 05:40:54 PM »

Hi Greg,

You need an rs232 to rs485 converter. The rs232 end goes into the computer. The RS485 end connects to the X200.  You will have to make this cable up. The converters usually have screw terminals on the RS485 end and a DB9 on the RS232 end.

You will need to buy Something like this.

http://cgi.ebay.com.au/RS232-RS485-DATA-COMMUNICATION-CONVERTER-ADAPTER-/140441135202?pt=AU_Components&hash=item20b2f1a862

Cheers,

Peter.

266

SmoothStepper USB / Re: SmoothStepper Modbus RPM DRO conflict

« on: December 15, 2010, 11:13:05 PM »

Greg,

If the spindle is assigned to port 0, Mach3 doesn't automatically issue a Modbus command. The user needs to set up the Modbus configuration to get the Modbus command sent to the Modbus device. The user then needs to write a brain to store the returned value into the TrueSpindleRPM variable.

If someone wants to do threading, then yes, a index sensor into the SS is required and it can not go through Modbus due to the latencies in the Modbus protocol.

So, if the user needs to do threading, they need an index sensor to be fed into the SS, and the SS will also be able to calculate the spindle speed.

Therefore there should never be a legitimate reason to want to get the spindle speed via Modbus and at the same time use a spindle sensor into the SS (or parallel port)  for threading.

Cheers,

Peter.

267

General Mach Discussion / Re: Heads up on CADCAM offer from Dolphin UK

« on: December 14, 2010, 05:44:59 PM »

Thanks Hood.

It seems like a good deal. I think I'll end up with the lathe module, but am just not ready yet to purchase. I still need to get my lathe finished.

Cheers,

Peter.

268

Modbus / Re: ModIO Expansion Limit

« on: November 23, 2010, 07:04:26 PM »

Hi,

To answer the easy question first.

Each ModIO has a RS232 to 485 converter on board.
The ModIO can communicate via RS232 or RS485.
So, You can have one ModIO connected to the PC and then have all other ModIO's daisy chained to the first via the RS485 port. The theoretical limit is 240. The RS485 drivers on the ModIO will support up to 32 ModIO devices on a bus.

Have a look at the example in the link below.It shows this setup.

http://homanndesigns.com/EN007-MC01R1.pdf

Using th new Modbus interface in Mach3 (Serial Plugin Support) you can setup 256 separate Modbus transactions. These can be to one or more ModIOs.

You then use Mach3 brains to interface between Mach3 internals and the Modbus data.


The Modbus Protocol is a very robust industrial strength interface. That said it has it's limitations. There are delays between Mach3 sending commands and getting back the replies. Therefore, you cannot use it for time critical motion control.  Home switches are also not suitable as there is an indeterminate delay (0-20ms) from when the switch is activated and when Mach3 receives the data.

To do Motion control, the ModIO would need to have a trajectory engine in it and take high level motion commands and then perform them.

Cheers,

Peter.

269

Show"N"Tell ( Your Machines) / Re: Taig CNC Lathe: First Run...

« on: November 15, 2010, 03:53:42 PM »

Hi Dave,

Thanks for the description. I understand and will give it a go.

Cheers,

Peter.

270

Show"N"Tell ( Your Machines) / Re: Taig CNC Lathe: First Run...

« on: November 15, 2010, 07:08:22 AM »

Hi Dave,

Are you using a Delrin nut on the cross slide as well? If so did you just copy the original bronze one?

Cheers,

Peter.