Frequently Asked Questions

In researching cnc plasma, some say do not use a high frequency start for the plasma cutter because it will interfere with the computer. What is your recommendation or experience with a high frequency start plasma cutter.

Avoid high frequency start plasma power supplies. They are little radio stations in the kilowatt range. They induce voltage into any piece of wire in close proximity.

I have heard of computers smoking and dieing ten feet away, not hooked up to any controller, turned on though. I only know for a fact that this happened once with a laptop in Texas. Could have been coincidence but it coincided with dry firing a plasma torch.

Shielding and grounding of the computer chassis can help alot. I think the best idea I have heard is to use a wireless keyboard and mouse, no matter what kind of plasma power supply is used.

I have had good luck with the HyperTherm PowerMax series of Plasma Power Supplies. There seems to be alot of space in the box, I have often thought it would be cool to put the motor controller right in with the plasma power supply.

Why would one choose a servo motor over a stepper motor? Or should they?

I like servo motors because: they are quiet, more power at high rpms, machines can move at least three times faster than steppers, rotational movement is smooth instead of jerky.

What I don't like about servos is: they cost alot more than stepper motors, the electronic drive is a whole lot more complicated, the motors have brushes which can wear out, the dissipation of heat is less efficient since the armature gets hot not the case like in a stepper motor, the shaft is not held firmly in place at rest, holding current is only applied when motor is off position, motors tend to chirp or buz when at rest, cabling can be a problem because of the mixing of encoder signals with power to the motor. It is best to gear down a servo motor to lead screws.

I like stepper motors because: they cost a lot less than servo motors, the cabling is simple and straight forward, the drive electronics can be very simple, the holding torque is greatest at low speeds, they are extremely reliable. A stepper motor can be mechanically bound and given full power with no determental effects, a servo motor would go bad in the same circumstance.

What I don't like about stepper motors is: the torque goes down when the speed goes up, they can not spin as fast as servo motors, they make sounds that correspond to the steps per second being sent to them, they can jam with no indication to the operating software.

There is no clear cut answer to your question. Mostly it boils down to economics, a machine with servo motors can operate faster, if you are making money with a machine it only behooves you have it operate as fast as possible. If the machine is going to be used for hobby purposes, stepper motors will suffice quite nicely.

I am looking into building a cnc plasma, and retrofitting a mill I have to cnc.
Nobel task to be sure.

Rather than piece everything, I wouldn't mind buying a kit to get me started quicker.My question for you is, for the plasma conversion, how do you propose to turn the cutter on and off during cuts, for cutting internal features, etc.?? obviously it would need to be automatic and via g codes to make the machine viable.
My controllers have two relays, one for torch or spindle the other is intended to be used to control coolant.

SuperCam has multiple machine type settings. The command 'setmech' lets the user change the machine type. When in 'Spindle' mode, Relay A turns on at the beginning of each motion sequence and off at the end automatically. When in 'Torch' mode, Relay A turns on at the beginning of each graphic item and off if start of next item is not the same as the current end.

The relays are manually toggled by keyboard keys 'Home' and 'End'.

There are three delays that can be set by the user. Initial delay, down delay and up delay. The intial delay is the time it takes for the spindle to spin up or the time the torch needs to clear the lines. The down delay is the amount of time required for the torch to perce the material or the z axis to settle out for a mill it occurs at the beginning of each graphic item. The up delay is the end each item.

SuperCam also uses M codes to control the relays from with in G-code file execution. M03 & M04 turn relay A on/off. M08 & M09 turn relay B on/off. The G04 followed by a P value for delay in seconds is also useful for torch operations using G-code files.

The SuperCam program lets you import DXF and HPGL files and execute the lines and graphic items directly on the attached machine. Many things can be done without the need to create G-code files.

Our controllers come with either switched power outlets or a terminal block that presents the relay contacts on the connector panel.

How do I delete the SuperCam demo version from my computer?
The scdemo.exe file that constitutes the demo version of SuperCam self expands to create 83 additional files, besides it's self, in the directory from which it is executed. Web page scfiles lists all the files found in an empty directory after executing scdemo.exe.

To remove SuperCam from your computer after executing the scdemo.exe file in the wrong place, delete the files in the list that have been place in the wrong directory. There are no modifications made to the registry or anything more complex than the 83 files being uncompressed into the host sub-directory.

Executing scdemo.exe in your Windows desktop will cause ICON's to be placed on your desktop screen. After deleting the files, delete the ICON's as well by right clicking and then choosing the 'delete' option.

How do I test the limits switches on my machine?
There is a command in SuperCam that is keyboard entry only, type in "switches" at the command prompt. SuperCam will immediately begin reading the status of the limit switches and display them on in the command area at the bottom of the screen.

When a Limit Switch is engaged|depressed the corresponding letter for that motor's axis will appear in the line repetively being displayed in command area. When using the EMC-XYYZ or EMC-XYYZB controllers, both Y Limit Switches must be engaged before the Y at limit status is sensed. If only one Y motor is being used the unused stepper motor connector can jumped from pin 8 to pin 9 to hardwire the unused limit switch circuit to the engaged condition.

ESC or SPACE on the keyboard will terminate the "switches" command.

When I want to save a machine configuration I cannot make that configuration the default setup the next time I turn on the program. How can I make my new machine configuration the default configuration?
SuperCam reads the MCHNCTRL.DAT file each time it is loaded.

To make a saved configuration the default configuration. Load the configuration file you want to make the default setup, by executing the "readmcfg" command either by using the pull down selection under FILES at the top left or keyboard entry. The execute the "savemcfg" command but this time make the file name to be saved "MCHNCTRL".

A lot of confusion has been caused by not realizing that once the "savemcfg" command has been run it sets up the file name of the configuration file to be save upon program exit to be the name of the file last saved using the "savemcfg" command. The next time SuperCam is loaded it reads the MCHNCTRL.DAT file which can be different that the file that was last saved, ergo confusion rains on the party.

Is SuperCam compatible with Windows Screen Savers?
When SuperCam is called from the Window Environment the screen saver program running in window will sometimes cause the box to lock up. Make sure screen saver is turned off or run in dos.

How can I use SuperCam while running Windows to edit tool path drawings?
First run SuperCam by calling it from a desktop shortcut. Once SuperCam is up and running, use the ALT-ESC keyboard combination to quickly switch between Windows and SuperCam.

How do I turn the Window's screen saver off?
In the Windows Desktop mode, Click START, then mouse to "Settings", then click CONTROL PANEL, then click DISPLAY, then click SCREEN SAVERS, then make the Selection (None).

How do I find the Port Address of the Parallel port adapter that is in my computer?
In the Windows Desktop mode, Click START, then mouse to "Settings", then click CONTROL PANEL, then click SYSTEM, then click DEVICE MANGER, then find and click on PORTS, find and click on PRINTER PORT (LPT1), then click on RESOURCES in the middle of the window it show the Input/Output Range. The first number is the address value used by SuperCam.

Running SuperCam Demo via the DOS window inside of Windows NT 4.0; it keeps locking-up or totally crashing. What is the problem?
Extend the printer port or paper out timeout to 10000 seconds in the printer setup for NT. This may or may not help.

There was no effort made to make SuperCam compatible with Windows NT. Your best bet is to boot the box directly to DOS mode. SuperCam considers the box completely at it's disposal, it is a real time machine control program. SuperCam was written it to be an embedded machine tool operating system dedicated to the operations of the attached computer controlled tool.

The best way to play with SuperCam is to create desktop shortcut to it by using the Windows Explorer. Right click on the SuperCam.exe file and drag and drop on to the Desktop area of your computer, then select the "shortcut" option. Once the shortcut is on your desktop right click on it to set the properties of the shortcut. The Windows Shortcut Setup web page is a screen save of the important properties.

Home Page at http://www.super-tech.com

Copyright 2016 Dennis Bohlke
Revised 03/12/16 dlb