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Parallel port confirmations
« on: January 28, 2017, 12:11:12 PM »
Hi all,

I'm currently configuring Mach3 to run my HDBB2, DG4S-08020 servo drives and ENI-1024 encoders.

I have a couple of questions regarding the parallel port outputs:

1. When testing the outputs from the LPT / parallel port I'm getting a 'high' of 3.4v and a 'low' of 0v. Is this correct? LPT is set to run in EPP mode with DMA3 selected in Bios. My BOB is TTL level and I can activate output relays connected to this.

2. With charge pump enabled on Pin 14, using a multimeter to test voltage output I get 1.7 - 2.2 volts depending. I know its difficult to read the CP output this way as its a 12.5 khz frequency, but does this sound roughly right and will it power the CP circuit on the HDBB2?

Thanks,
Jim
Re: Parallel port confirmations
« Reply #1 on: January 28, 2017, 11:42:43 PM »
Hi,
what PC are you running, most older style machines have high TTL output of 5V. Laptops commonly have lower levels, 3.3V.

Depending on your BOB 3.3V may not be enuf to reliably trigger a BOB output.

Craig
My wife left with my best friend...
     and I miss him!
Re: Parallel port confirmations
« Reply #2 on: January 28, 2017, 11:49:08 PM »
Hi (again),
the charge pump sounds about right, it is a 50% duty cycle square wave and your multimeter is sort of averaging it out,
often not easy to read.

(3.3V+ 0V)/2=1.65V or there abouts. It sounds to me that your PC is doing what it should but it is most certainly a 3.3V output
machine. Do you have a manual for your BOB? Some accommodate lower input voltages and some don't.

Craig
My wife left with my best friend...
     and I miss him!
Re: Parallel port confirmations
« Reply #3 on: January 29, 2017, 07:17:13 AM »
Hi Joe,

I'm running a Dell Optiplex 755 with Windows XP Pro 32 bit and a CNCDrive HDBB2 break out board;

http://www.cncdrive.com/downloads/HDBB2_manual.pdf

It doesn't actually say whether the board supports 3.3v lpt ports in the manual. Like I say though I am able to activate outputs on the BOB. The only thing I'm unsure is, is the charge pump.