Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Quin on November 05, 2012, 07:52:56 PM

Title: Outputs on at startup
Post by: Quin on November 05, 2012, 07:52:56 PM: If I turn on my machine after a computer boot-up and then make a home switch active (active low), outputs #1 & 2 become active (active high). This condition goes away after cycling the home switches a few times. It only happens after a computer boot-up. Any solutions??
Title: Re: Outputs on at startup
Post by: Fastest1 on November 06, 2012, 05:25:46 PM: Do you have the charge pump enabled?
Title: Re: Outputs on at startup
Post by: Quin on November 06, 2012, 06:58:25 PM: I do not have a charge pump. The Enable pin has 5volts all the time. I was considering adding a charge pump so I simulated its action by putting a switch in the 5v line to the EN pin. When I power up the system without EN at 5v, the steppers flutter and sputter. This lead me to believe that the cause is elsewhere.
Title: Re: Outputs on at startup
Post by: Fastest1 on November 06, 2012, 07:25:53 PM: What BOB and drivers are you using?
Title: Re: Outputs on at startup
Post by: Quin on November 06, 2012, 08:45:33 PM: Using a C10 BOB from CNC4PC and Gecko G-201X drivers
Title: Re: Outputs on at startup
Post by: Quin on November 07, 2012, 06:12:19 PM: Fastest1,

Any more thoughts on this one?

Quin
Title: Re: Outputs on at startup
Post by: BR549 on November 07, 2012, 06:34:59 PM: IF your drivers are not enabled they should NOT even twitch much less move. WHen a PC boots up it twiddles the LPT ports looking for things. This will cause movements IF you have the drives enabled without a chargepump.

Best bet is to boot up with the drives turned OFF then after the Computer is fully online turn the drives on. OR just use a charge pump circuit.

(;-) TP
Title: Re: Outputs on at startup
Post by: Quin on November 07, 2012, 08:38:30 PM: A point of clarification, outputs 1 and 2 are for mist and flood cooling which are the problem. They (pins 1 & 14) energize solid state relays. The stepper motor outputs react perfectly at computer boot up.

Quin
Title: Outputs on at startup
Post by: Fastest1 on November 08, 2012, 07:45:50 PM: I run a PMDX 126 and don't need any extra parts to enable the charge pump. I set it up in Mach. I would think it works the same way.