RS-485/MODBUS
- Thread starter bob_mllr
- Start date
RS-485 / MODBUS was removed from G3 as this feature was not being used.
testyourdesign
testyourdesign
@bob_mllr
Most VFD's have the ability to be controlled using a 0-10V function and have external control pins to control functions like direction, start, stop, or alarm. Take a look at your VFD's documentation to confirm but in my experience, most VFD's will work with Masso.
PS is this the Bob Miller I know from IG?
Cheers, Stephen Brown
Most VFD's have the ability to be controlled using a 0-10V function and have external control pins to control functions like direction, start, stop, or alarm. Take a look at your VFD's documentation to confirm but in my experience, most VFD's will work with Masso.
PS is this the Bob Miller I know from IG?
Cheers, Stephen Brown
Hi Stephen,
Yes - it is I - I saw you on here and expected you might chime in
. And yes, I was thinking about using the 0-10V input. All that is supported on the Baldor VFD I have. I've decided to make a new control panel - tired of balancing the monitor, keyboard and mouse on the current shaky platform - do it a little more proper So just looking at options, trying to keep the cost down. I do like the Masso idea of a fully self contained unit, and made locally. But I also like the idea of Mach4 on a PC with an ESS smoothstepper and the current PC as it is a lot cheaper. Probably even just use Mach3 which I have a license to for now.Does Masso spindle output allow setting motor speed for different pulley ratios?
Cheers, Bob
testyourdesign
testyourdesign
@bob_mllr
I thought that was you! Welcome to the forum
The Masso settings menu allows you to adjust the spindle 100% duty output RPM to a custom value so you can calibrate the requested RPM with the actual spindle RPM. If you recall I use a 7000 rpm spindle with a gear reduction between the motor and the spindle. I have my spindle settings adjusted so that rpm requested from Masso translates to roughly to the correct rpm at the spindle even though the motor is actually running at a much higher rpm.
After setting it up I ran a bunch of tests at different RPM's and found the output request did not track as precisely as I had hoped over the entire range. At first, I was disappointed and tried to figure out how to fix it but then I realized that most of what I do is either between 4000 and 5000 RPM or 1500 to 1800 RPM. After running a bunch more tests in those RPM ranges, I found it to be within 10% of the requested RPM so its perfectly fine for what I needed. The results will probably be different on every VFD or Servo Driver combination out there so its something that you will need to test for your application.
The nice part of the old Mod Bus request is that it allows the VFD to control the actual RPM so it is much more precise than the 0-10v control. However, in my past experience with a Mod Bus setup on a Mach 3 CNC router, I found RS485 to be very susceptible to EMI and could not be run a long distance from the PC. Those issues were a problem for my application so I tried it, discovered the drawbacks, and reverted to 0-10v control afterward.
Sounds like you only need a few tweaks to update your system so it's probably more cost-effective to stick with what you are used to but I found this to be a very capable controller for my CNC mill conversion.
Cheers, Stephen Brown
I thought that was you! Welcome to the forum
The Masso settings menu allows you to adjust the spindle 100% duty output RPM to a custom value so you can calibrate the requested RPM with the actual spindle RPM. If you recall I use a 7000 rpm spindle with a gear reduction between the motor and the spindle. I have my spindle settings adjusted so that rpm requested from Masso translates to roughly to the correct rpm at the spindle even though the motor is actually running at a much higher rpm.
After setting it up I ran a bunch of tests at different RPM's and found the output request did not track as precisely as I had hoped over the entire range. At first, I was disappointed and tried to figure out how to fix it but then I realized that most of what I do is either between 4000 and 5000 RPM or 1500 to 1800 RPM. After running a bunch more tests in those RPM ranges, I found it to be within 10% of the requested RPM so its perfectly fine for what I needed. The results will probably be different on every VFD or Servo Driver combination out there so its something that you will need to test for your application.
The nice part of the old Mod Bus request is that it allows the VFD to control the actual RPM so it is much more precise than the 0-10v control. However, in my past experience with a Mod Bus setup on a Mach 3 CNC router, I found RS485 to be very susceptible to EMI and could not be run a long distance from the PC. Those issues were a problem for my application so I tried it, discovered the drawbacks, and reverted to 0-10v control afterward.
Sounds like you only need a few tweaks to update your system so it's probably more cost-effective to stick with what you are used to but I found this to be a very capable controller for my CNC mill conversion.
Cheers, Stephen Brown
Thanks Stephen,
I understand. I've not had any problems with the RS485 on my current system and do like the precise speed control FWIW. I have a brain in Mach3 that knows the pulley ratios so all I have to do is select which pulley combo is set and the brain will set the motor speed correctly for the desired spindle speed. And I can also switch the spindle to manual and use a pot with the 0-10V input. Still considering Masso though.
I've got a 10" touch screen coming tomorrow - not sure if that will be too small though. Anyway, still mulling it all over.
Cheers, Bob
I understand. I've not had any problems with the RS485 on my current system and do like the precise speed control FWIW. I have a brain in Mach3 that knows the pulley ratios so all I have to do is select which pulley combo is set and the brain will set the motor speed correctly for the desired spindle speed. And I can also switch the spindle to manual and use a pot with the 0-10V input. Still considering Masso though.
I've got a 10" touch screen coming tomorrow - not sure if that will be too small though. Anyway, still mulling it all over.
Cheers, Bob