Fingers crossed it'll cut ally

[templecorran]

Excuse me,
The PC parallel port outputs a binary signal, meaning it has two levels, off / on; or 0 / 1. The 0 is represented by a voltage less than 0.8v The 1 represented by a voltage greater than 2.4v.
Because the signal of interest is a PWM waveform, the voltmeter will be showing the average of the highs & lows of the signal. PWM means Pulse Width Modulation. By varying the proportion of ON time to OFF time in a given interval (20ms) the resulting effect is an analogue voltage. If the ESC wants a true analogue voltage input, a small value capacitor (1μF) between signal pin and ground will help.
If you have access to an oscilloscope this would all be really clear.
Thank you class for being attentive. Now, run along and play with your nice machines!

Oh! I just answered my own problem! Use the oscilloscope to monitor the output of the PWM line (from Mach3), and see how similar it is to the DCBLM drive module requirement!!

[blackburn mark]

Oh! I just answered my own problem! Use the oscilloscope to monitor the output of the PWM line (from Mach3), and see how similar it is to the DCBLM drive module requirement!!

errrr.... let us know if you make any sense of the problem or if you use the capacitor, im asuming you already have an ESC and servo tester ?

[Jonathan]

...signal of interest is a PWM waveform, the voltmeter will be showing the average of the highs & lows of the signal...If the ESC wants a true analogue voltage input, a small value capacitor (1μF) between signal pin and ground will help

The ESCs we're using require a PMW signal with 20ms period. The range of the duty cycle used by the ESC is only roughly 5% to 10% - which means you don't get a very high resolution with mach3 connecting it directly. Only a handful of speeds in fact. Still probably sufficient in reality, but not ideal - hence why I'm still interested in investigating the servo tester adaptation. I agree a capacitor will certainly be required here, since the PWM signal is being fed into an ADC.

Just out of interest I connected my model car transmitter up to the parallel port yesterday in a similar fashion - it works fine which implies the servo tester conversion should also. I'm trying to control the parallel port in C now, so I can get the car driving itself around...

[blackburn mark]

there are two things im dreading on this build....
hole sawing 25mm for the Y screw and drilling and tapping the bed plate

up to now iv used my diy spindle to do all my drilling and i was gagging to to be able to say id done the whole build with it and a tiny cowells 90 lathe:dance: however.... i think i may need to stop f***ing around and borrow a heafty drill

there is probably loads more stuff i should be flapping about but at this point i cant see past the drilling and tapping..... more drilling and tapping.... and!!!..... b***cks!!


for now i decided not to support the floating bearing on the Z screw, the housing that came with it seem such a waste of valuable space... ill make a low profile one if i have trouble with it whipping around