On Sat, 2011-11-05 at 09:30 -0700, Kirk Wallace wrote: ... snip > Most real machines (my opinion) use 12 Volts for control signals to help > push the noise into the OFF voltage region. ... snip
Another thing I just read about. Having a resistor in series with the opto-coupler input (LED anode) and another from the input to the signal return (LED cathode) forms a voltage divider. Adjusting the values of the resistors allows one to set the voltage which the opto-coupler turns on. If you have a 4.5 Volt signal, the divider can be set to turn the opto-coupler on at 3.5 or 4 Volts input to the divider. If noise is no greater than 3 Volts, the opto-coupler won't trigger on the noise. Or at least that's the plan. See Figure 7: http://www.fairchildsemi.com/an/AN/AN-3001.pdf -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
