I have an old SuperCam controller I used for a 3 axis cnc carving machine about 15 years ago.
I should now like to drive it using a mega 2560, but the input to the controller is a 25 pin parallel port. Is this possible ? (cct diagram of part of the controller attached)
MTIA,
John
What do You know about the signals passing the 25 pin port?
Assume the answer to be 'very little'.
The original set up used the Supercam software to produce G-code, which by some magical process in the software, was outputted(is that a real word?) as a digital stream via the port to the controller.
John
I'm sorry to say but then little or no help to get.
G-code has no connection to any multipin connector.
What technical documentation have You got? Wiring diagrams, service manual etc.?
DB25F connector and the pinout looks like a standard computer parallel port interface. Driving that would be fairly simple, just standard TTL level signals. The difficult part is determining the signal timing for the various functions. You could probably take some pre-existing CNC control code like GRBL and modify the output section.
This looks promising. My first task is to try sending some signal into the connector that would trigger some reaction from the motors. (I assume that a +5v level would be appropriate for a 'high' and 0v for a low,)
However, at this stage I'm not sure what the majority of the pin labels mean.
STB I assume is 'strobe' but does that mean in this context ?
The pins with D0 - D7 are self explanatory, as inputs to the 244 buffer, but that seems to need an 'enable' signal (5v?) to get an output.
I've just realised I need to attach the whole cct diagram !
More to follow.
Intro - I'm an 85 yo, with my electronics background being military training 60 years ago !
Still remember how to read digital ccts, but keeping the old grey cells in working order becoming more of a challenge.
John
EMC-XYYZB-Schematic.pdf (162.1 KB)
The 244 is likely a 74LS244 or similar, which has an output enable control. In this case, it looks like the output is enabled when the Autofeed signal is low and *init is high (the asterisk indicating an active-low signal).
The L297 seems to be an STMicroelectronics stepper motor controller.
No idea what U7 and U8, labeled PUU, are. Some type of parallel to serial chip by the looks of it
Most of the circuitry is just stepper motor drivers, and some limit switch circuitry that is fed back to the controller.
I now realise that I feel much more comfortable with building my own system from scratch, so I've downloaded Grbl, and installed it on my mega board, and started looking for a shield and drivers.
Wish me luck !
Thanks all for kick starting me.
John
PS is there any difference in the cnc shields for the different arduino boards , as I've got a mega2560, and don't want new problems !
Ive swapped a few cncs most recently was a router with included control box something like a 6040 but it required par port and i didnt want to modify it (well not yet atleast) so i use grbl loaded on a nano with a screw terminal sheild and cut up old par cable. This way it uses the factory drivers and connections i just plug my nano/par cord into the par socket and then usb from nano to computer and run it just like any other grbl machine
Ah, a 'man(?) after my own heart'. Thanks for the heads up. I've already started by ordering some new kit, but taking out the 24v psu from the original controller box, plus fans.
Currently struggling to make sense of the pinout of the original powermax 2 steppers that I shall use, along with the 9 pin connectors and cabling which is already on the cnc I've built
Regards
John
Ends up pretty simple. Think i ended up using 7 or 8 pins on the db25 connector. Just found grbl pinout vs par port pinout then just cross one to the other. Also did one that didnt have a controller it now has grbl on nano with 3 tb6600 drivers i believe
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