Smithy 1240 Linux to Mach3

[Grayson]

We would very much appreciate your assistance in getting our Smithy 1240 running with Mach3. Briefly, the spindle does not operate correctly and we seek advice from someone with more expertise.  I am having a time trying to learn all the technical aspects of the electronics and what the parameters should be in the Mach3 software. I think we are close but just do not have the technical knowledge to get the project finished.
The X,Y and Z axes seem to be working fine after using the auto setup found in Mach3. The limit switches and homing are working as expected.  The central problem is controlling the spindle. An m3 or m4 code both result in forward rotation of the spindle.  The actual and commanded speed (using an s command in a program or in the MDI tab) of the spindle is different. The maximum speed should be 4000 rpm and we are producing about 3500 or less. The worksheet from the PMDX website and a note on a similar thread really helped. We removed the linearity.dat file from about four places in the Mach3.
When we purchased the machine the original EZTROL system was abandoned in favor of a desktop computer using the printer port and a cable to the PMDX-110. The computer had a dual boot Windows XP and Ubuntu operating system with LinuxCNC running the mill.  A prior owner loaded Windows XP on the computer along with Mach3. We gave Mach a quick try but did not get good results. We used LinuxCNC to run the mill for a couple of years and due to a litany little problems with LunuxCNC we decided to shift to Mach3 after a fresh installation of Windows XP.

C300 series of Inverter Manual (Sunfar)
www.sion.rs/download/sunfar/C300manual.pdf

C300 VFD setting for Smithy 1240 (Smithy)
http://server2.smithy.com/media/pdf/c300vfd_settings.pdf

Connections at the C300 from the PMCX-110
GND     two wires violate and orange
FWD     Black wire
REV       Red wire
VC          Nondescript color
Cable colors change due to loom make up leading from C 300 to PMDX-110. We can trace if necessary.
Wires and the switch settings at PMDX-110 can be seen in the attached photo of the board.

Motor Information (difficult to see clearly)
ANHU Wannan Electric Machine Co LTD
Type   YVF2-90L-4
No.  4715182
Voltage 220
Hz   60
RPM   ?
Ins Cl  F

[Steve Stallings]

Along the top edge of the PMDX-110, there is a small blue potentiometer with a
screwdriver adjustment slot. It is labeled Max Speed. This is used to set the
maximum control voltage sent to the VFD. Rotating it clockwise may increase
the speed that you can get from your spindle.

The fact that your spindle always goes the same direction may be caused by
configuration problems in Mach3. There is an XML file in your Mach3 folder that
stores your configuration. Look for the one that matches the name that shows
box labeled PROFILE in the lower right corner of your Mach3 screen (assuming
you are not running a custom screenset). For example if your PROFILE shows
as Mach3Mill, then the file is Mach3Mill.xml for your configuration. Please post
that so we can check it for you.

[Grayson]

Steve,
We are making some progress in that the spindle can be driven FWD and REV. However the RPM continues to be a problem. Running too slow at top spindle speed even after turning the pot all the way up.

We tried the VSD speed calibration routine for the PMDX-106 and found no improvement in max RPM.

Here is the XML file as it stands with the spindle running both directions. Additionally a plot of the RPM over a range of M3 commands.

Thanks
Grayson

[Bob at PMDX]

I'm going to jump in here for a second.  If you have a volt meter or DMM, command the spindle to 4000 RPM (presuming you are using spindle pulley #1).  Then measure the voltage between connector J2 pin 5 (VFD control voltage) and J2 pin 6 (analog ground).  Pin 6 is the furthest away from the "J2" designator on the silkscreen, and just above the "S" in "Spindle Motor Drive".

Best would be to make 2 measurements.  One with the VFD disconnected from J2, and again with the VFD connected (and powered on).  Ideally you should measure something very close to 10 volts DC.

WARNING: If you measure this while these signals are connected to the VFD, the "analog ground" on pin 6 will be floating relative to chassis/safety ground and MAY BE AT THE LINE VOLTAGE!  Do not touch the traces or connector pins with your hands or fingers.  Use only insulated meter probes.

[Grayson]

Hi!
After checking the pot to make sure it was at the upper limit stop.

We used a digital meter and produced the following results:
With the connector off of the J2    9.89 Volts.
With the connector on the J2        9.82 Volts.

Thanks
Grayson

[Bob at PMDX]

I am about to exceed my knowledge of VFDs.  That said, if the PMDX-110 is outputting 9.82 or 9.89 volts to the VFD, AND presuming that the VFD is programmed so that 10V in results in 4000 RPM of the spindle (a big *if*), then you should be getting (9.8/10)*4000 = 3920 RPM.

From your graph it looks like you are getting somewhere around 3100 or 3200 RPM.  This is about 77% of 4000 RPM.  This makes me think that perhaps the VFD is not configured correctly, or there is something in the wiring between.

For kicks, command the spindle to 4000 RPM again in mach and measure the voltage AT THE VFD between the "VC" and "AV0" terminals.

hmmm... the VFD manual that you gave a link to is inconsistent in what it calls the analog input "common" terminal.  In section 3.5, the picture shows the terminal labeled "AV0" (as in Analog Voltage Zero, or analog ground).  But the below that diagram says "GND", which is also the name of the digital ground terminal next to FWD and RST.  I think this is a typo and in the analog input section of that table it should say "AV0".

So...  please verify that the "AV0" terminal on the VFD is connected to the pin 6 of J2 on the PMDX-110 board.  Also, generally speaking, the "AV0" and "GND" terminals on the VFD should NOT be connected together.  It kind of looks like they might be from your original wiring description of "GND - 2 wires violet and orange".

If you changed any wiring above, re-measure the voltage at the VFD between the "VC" and "AV0" terminals when commanded to 4000 RPM.

One final test: disconnect the wire from the VFD "VC" terminal and jumper the "VS" terminal to the "VC" terminal.  This will provide 10V from the VFD to the control input and *should* run the spindle at full speed.  See if that causes the spindle to run at 4000 RPM.  If not, and if "VS" to "AV0" measures 10V, then something is not correct in the VFD configuration.

Bob

[Grayson]

Hi Bob,
We are reasonably sure that the Sunfar C300 is a Model 2S0022.

We traced the wires from the PMDX-110 up to the terminals on the C300 and here are the results.

J2              C300
Pin             Terminal Strip
2                GND
6                GND
1                FWD
3                REV
5                VC

Thanks
Grayson

[Grayson]

Dave,

We first measured the voltage between the VC and the AVO terminals and found 1.8 volts.

We removed the wire from the VC terminal on the C300 and jumped VC and VS. The spindle RPM by direct measure was only 3162.

Thanks
Grayson

[Bob at PMDX]

First - I was mis-understood what the "AVO" terminal is.  It is an analog output terminal, not the analog ground reference.  Sorry about that.

If you connect VS to VC and still get only 3162 RPM on the spindle, then either some parameter in the VFD is not set properly or the VFD is defective.  First, with VS tied to VC, measure the voltage from VC to GND.  It should be VERY close to 10V.  Then review the VFD parameters.  I can't tell you how the VFD *should* be configured other than I presume it should match the Smithy document that you gave us a link to.  None of the "frequency" settings look (to me) any way related to 4000 RPM, but then I don't know if there is a non 1:1 pulley or gear system on the spindle, or an electronic "gear ratio" in the VFD.  And this goes beyond my knowledge of VFDs (at least without better explanations of the configuration parameters).

If/when you get the spindle up to 4000 RPM with VS tied to VC, then you can re-connect the PMDX-110 to the VC terminal and go through the PMDX-110 spindle speed calibrate process to get the trim pot set correctly.

Bob

[Grayson]

Bob,
We will do some more exploration into the VFD parameters.
We really appreciate your help with this project. Your guidance is really important to us.
We will press on and let you know what happens.
Thanks
Grayson

[Grayson]

The Smithy 1240 mill spindle is running at full RPM.  Thanks to Bob, Steve and fc60 we assembled enough information to get our mill running properly. The PMDX-110 board is rather old yet it is functioning just fine and PMDX continues to support the product. I think those are hallmarks of a really fine company.
Cheers
Grayson