i have a z axis which as a dc 24 volt motor on it, not a stepper motor will this work with masso and a proma 150 .this is the first machine i have built using the masso, before this i have built a rotary plasma cutter using a chinese controller and fl-pipe software which i use for all the tube work on our chassis's ,this as run faultless for the last 2 years
z axis plasma
- Thread starter mk
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zombieengineer
ZombieEngineer
@mk there was a similar posting several days ago: https://www.masso.com.au/forums/topic/dc-24-volt-torch-height-lifter-2/
Disclaimer: the following is a theoretical answer - I don't have a plasma cutter.
If the Torch Height Controller (THC) can supply TTL (0-5V) Raise / Lower signals then get a L298N board to drive the torch lifter rather than using Masso (see attached photo for an example board).
The L298N can take 4 TTL inputs (0-5V) and provide 4 motor drive level outputs (5-35V, 2A per output).
You would connect the 24V lifter motor wires to two of the L298N outputs and the THC Raise/Lower to the respective inputs.
Providing the Raise / Lower signals are different (one signal is high and the other is low) the motor will turn and the lifter will raise/lower (if it goes in the opposite direction, reverse the motor wires).
Disclaimer: the following is a theoretical answer - I don't have a plasma cutter.
If the Torch Height Controller (THC) can supply TTL (0-5V) Raise / Lower signals then get a L298N board to drive the torch lifter rather than using Masso (see attached photo for an example board).
The L298N can take 4 TTL inputs (0-5V) and provide 4 motor drive level outputs (5-35V, 2A per output).
You would connect the 24V lifter motor wires to two of the L298N outputs and the THC Raise/Lower to the respective inputs.
Providing the Raise / Lower signals are different (one signal is high and the other is low) the motor will turn and the lifter will raise/lower (if it goes in the opposite direction, reverse the motor wires).
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@zombieengineer
@mk
Disclaimer: the following is a theoretical answer - I don't have a plasma cutter.
ZombieEngineer.
You are on the right path with what your disclaimer says - theoretical.
I have been playing with this scenario by using a 12 or 24v dc motor with the THC comparator board.
A simple 12 and 24v servo motor (dc motor ) without the encoder works every time with the up / down signals.
The encoder can be connected to the Masso ??? ( have done it with other controllers )
I have put the encoder back into DeskCNC, by swapping axis through relays to a pulsar board.
Not sure about how encoders work with Masso yet.
But servo motors work fine for differential movement so far.
You have just shown a way to do away with the stepper or servo drivers with that little board.
And use a standard DC motor.
As the THC gives signals to the Masso, Masso outputs 3.45 to 5v positives signals for the up / down movement with the M667 running.
This board will do it, they are now ordered to complete the puzzle.
Thanks and cheers.
@mk
Disclaimer: the following is a theoretical answer - I don't have a plasma cutter.
ZombieEngineer.
You are on the right path with what your disclaimer says - theoretical.
I have been playing with this scenario by using a 12 or 24v dc motor with the THC comparator board.
A simple 12 and 24v servo motor (dc motor ) without the encoder works every time with the up / down signals.
The encoder can be connected to the Masso ??? ( have done it with other controllers )
I have put the encoder back into DeskCNC, by swapping axis through relays to a pulsar board.
Not sure about how encoders work with Masso yet.
But servo motors work fine for differential movement so far.
You have just shown a way to do away with the stepper or servo drivers with that little board.
And use a standard DC motor.
As the THC gives signals to the Masso, Masso outputs 3.45 to 5v positives signals for the up / down movement with the M667 running.
This board will do it, they are now ordered to complete the puzzle.
Thanks and cheers.
zombieengineer
ZombieEngineer
@lilow - Please let us know if using a L298N board works out. Would like to move this from "Theoretical" to "Proven".
Be aware that the simple 5V regulator on these boards (2 and half legs on one side and a wide tab on the other) are likely to overheat when used with 24V power supply. From a voltage regulator datasheet - expect 50C rise above ambient temperature. You may need to remove a jumper and provide an external 5V supply to the L298N board or fit a small heat sink to the voltage regulator.
Be aware that the simple 5V regulator on these boards (2 and half legs on one side and a wide tab on the other) are likely to overheat when used with 24V power supply. From a voltage regulator datasheet - expect 50C rise above ambient temperature. You may need to remove a jumper and provide an external 5V supply to the L298N board or fit a small heat sink to the voltage regulator.
Ok @zombieengineer.
I'd like some input.
One is that it could only be used with the ( dir only ) from the Masso. ( high / low )
Second, you would have to use both outs on that board.
Third, if no signal is generated, the dc motor is in free fall.
Fourth, the THC has to be set in Masso so that it constantly hovering between ccw /cw from a really fine setting of the THC or by using a resistive Z axis.
So the answer would be a reduction drive dc motor.
Feel free to contact me.
Cheers.
I'd like some input.
One is that it could only be used with the ( dir only ) from the Masso. ( high / low )
Second, you would have to use both outs on that board.
Third, if no signal is generated, the dc motor is in free fall.
Fourth, the THC has to be set in Masso so that it constantly hovering between ccw /cw from a really fine setting of the THC or by using a resistive Z axis.
So the answer would be a reduction drive dc motor.
Feel free to contact me.
Cheers.
zombieengineer
ZombieEngineer
@lilow
My recommendation was to connect the Raise/Lower signals from the Plasma Torch Height Controller (THC) to the L298N board. Masso has no control over the position of the torch.
The "simple DC motor lifter" (see previous forum post Dc 24 volt torch height lifter for a photo). It is a 24V DC motor with a reduction gear connected to a ball screw. The black cylinder is the motor while the lower silver cylinder will be the reduction gears. There was a follow-up posting that the lead screw is actually a ball screw (we will come back to that).
I had a look at a manual online for a typical THC (specifically Hypertherm) to understand how this simple lifter is actually meant to work. It appears that when the arc is turned off the THC requests the torch to be lifted until the upper limit switch is reached. When the arc is requested on the THC lowers the torch until an arc is struck, the height is adjusted until a stable arc and then an "Arc OK / Motion allowed" is sent to the CNC machine. This sort of configuration is potentially inefficient if you are doing a lot of intricate piercing work (start / stop the arc) as the torch will be traveling several inches up and down with each arc strike. For typical factory floor cutting the length of the cut segment is not a couple of centimeters but closer to a meter linear length - the up/down bob is a small amount of time compared to cutting.
I need to post a drawing of how this links together but my laptop is "having issues" (mandatory software upgrade from IT broke stuff).
Second, you would have to use both outs on that board.
There are a couple of things here - 24V 2A => 48W, that is enough power to lift 5 Kg at 1 meter/sec (that sounds fast enough to me). Ball screws are typically >90% efficient and the reduction gear box should be 80% efficient. The L298N datasheet on page 7 has the following statement / warning:
You can check the datasheet - Channel 1 is on the far left of the IC and channel 4 is on the far right. Which terminals on the PCB they are connected to is a bit of a lucky dip.
My guess would be: (strictly an educated guess)
This lifts the current rating close to 4A (this would have the torch head really moving). Trying to explain the gotcha for parallel output didn't appear to be worth it at the time - but since you asked you now have the gritty detail.
Third, if no signal is generated, the dc motor is in free fall.
If the both outputs are high or both outputs are low then the two wires of the DC motor are effectively connected together - this acts as a brake. Grab a loose DC motor and spin the shaft, next short the two terminals / wires together and then try to turn the motor - it should still turn but will have significantly more mechanical resistance. What is happening is the DC motor turns into a generator and mechanical power is converted to electrical power which is converted into heat by the motor winding resistance.
Secondly the reduction gearbox should provide enough mechanical resistance to avoid the "free fall" scenario.
Fourth, the THC has to be set in Masso so that it constantly hovering between ccw /cw from a really fine setting of the THC or by using a resistive Z axis.
The THC will be doing the "dithering" to maintain the correct height - it measures the arc voltage using a voltage divider and then constantly sending short pulses up/down to adjust the position. Masso moves the X/Y axis when the THC says the arc is OK. As mentioned in the response from the previous point - the DC motor acts as a brake together with the resistance of the reduction gears, very unlikely to move on its own.
The appendix of the Hypertherm manual requires the lifter to have 2 mm/rev ball screw and capable of moving at 200 in/min. This works out to be about 2500 RPM. A quick hunt on eBay turns up a suitable motor rated at 2400 RPM, 24V, 2.4A at full load (no reduction gears required, hmm...).
Hopefully this has covered off your questions (apart from wiring - need to know the model of your THC to advise further).
EDIT: The silver cylinder could actually be the DC Motor to Ball screw coupling - not a reduction gear. The photos don't provide enough detail.
My recommendation was to connect the Raise/Lower signals from the Plasma Torch Height Controller (THC) to the L298N board. Masso has no control over the position of the torch.
The "simple DC motor lifter" (see previous forum post Dc 24 volt torch height lifter for a photo). It is a 24V DC motor with a reduction gear connected to a ball screw. The black cylinder is the motor while the lower silver cylinder will be the reduction gears. There was a follow-up posting that the lead screw is actually a ball screw (we will come back to that).
I had a look at a manual online for a typical THC (specifically Hypertherm) to understand how this simple lifter is actually meant to work. It appears that when the arc is turned off the THC requests the torch to be lifted until the upper limit switch is reached. When the arc is requested on the THC lowers the torch until an arc is struck, the height is adjusted until a stable arc and then an "Arc OK / Motion allowed" is sent to the CNC machine. This sort of configuration is potentially inefficient if you are doing a lot of intricate piercing work (start / stop the arc) as the torch will be traveling several inches up and down with each arc strike. For typical factory floor cutting the length of the cut segment is not a couple of centimeters but closer to a meter linear length - the up/down bob is a small amount of time compared to cutting.
I need to post a drawing of how this links together but my laptop is "having issues" (mandatory software upgrade from IT broke stuff).
Second, you would have to use both outs on that board.
There are a couple of things here - 24V 2A => 48W, that is enough power to lift 5 Kg at 1 meter/sec (that sounds fast enough to me). Ball screws are typically >90% efficient and the reduction gear box should be 80% efficient. The L298N datasheet on page 7 has the following statement / warning:
For higher currents, outputs can be paralleled. Take care to parallel channel 1 with channel 4 and channel 2 with channel 3.
You can check the datasheet - Channel 1 is on the far left of the IC and channel 4 is on the far right. Which terminals on the PCB they are connected to is a bit of a lucky dip.
My guess would be: (strictly an educated guess)
- Outlet terminal on the left closest to the IC is channel 1
- Outlet terminal on the left farthest from the IC is channel 2
- Outlet terminal on the right farthest from the IC is channel 3
- Outlet terminal on the right closest to the IC is channel 4
This lifts the current rating close to 4A (this would have the torch head really moving). Trying to explain the gotcha for parallel output didn't appear to be worth it at the time - but since you asked you now have the gritty detail.
Third, if no signal is generated, the dc motor is in free fall.
If the both outputs are high or both outputs are low then the two wires of the DC motor are effectively connected together - this acts as a brake. Grab a loose DC motor and spin the shaft, next short the two terminals / wires together and then try to turn the motor - it should still turn but will have significantly more mechanical resistance. What is happening is the DC motor turns into a generator and mechanical power is converted to electrical power which is converted into heat by the motor winding resistance.
Secondly the reduction gearbox should provide enough mechanical resistance to avoid the "free fall" scenario.
Fourth, the THC has to be set in Masso so that it constantly hovering between ccw /cw from a really fine setting of the THC or by using a resistive Z axis.
The THC will be doing the "dithering" to maintain the correct height - it measures the arc voltage using a voltage divider and then constantly sending short pulses up/down to adjust the position. Masso moves the X/Y axis when the THC says the arc is OK. As mentioned in the response from the previous point - the DC motor acts as a brake together with the resistance of the reduction gears, very unlikely to move on its own.
The appendix of the Hypertherm manual requires the lifter to have 2 mm/rev ball screw and capable of moving at 200 in/min. This works out to be about 2500 RPM. A quick hunt on eBay turns up a suitable motor rated at 2400 RPM, 24V, 2.4A at full load (no reduction gears required, hmm...).
Hopefully this has covered off your questions (apart from wiring - need to know the model of your THC to advise further).
EDIT: The silver cylinder could actually be the DC Motor to Ball screw coupling - not a reduction gear. The photos don't provide enough detail.
Ross
Ross
It might be best to pull the motor off and check what makes it tick.
Then if possible replace the motor with a Nema 23.
Problem solved the easy way.
These lifters come in two motor types, it's just that he bought the wrong type to suit Masso, Simple mistake that's all.
The other thing is hitting limit switches when it lifts will probably cause Masso to stop or throw a hard limit or,, soft limit when it doesn't know where it is (counting steps past it's Z axis travel limits that is)
From Ross.
Then if possible replace the motor with a Nema 23.
Problem solved the easy way.
These lifters come in two motor types, it's just that he bought the wrong type to suit Masso, Simple mistake that's all.
The other thing is hitting limit switches when it lifts will probably cause Masso to stop or throw a hard limit or,, soft limit when it doesn't know where it is (counting steps past it's Z axis travel limits that is)
From Ross.
@zombieengineer.
Thanks for getting back.
@mk asked a question of how it could be done.
Maybe can't, but at least others could see a virtue in his request for some information.
You may have supplied an answer.
It can not proceed until the board suggested is delivered.
Cheers.
Thanks for getting back.
@mk asked a question of how it could be done.
Maybe can't, but at least others could see a virtue in his request for some information.
You may have supplied an answer.
It can not proceed until the board suggested is delivered.
Cheers.