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Post by Fastest1 on Sept 25, 2011 10:12:06 GMT -8
Dave, I talked to Steve @ PMDX in regards to the 126. I would like use the probe and a touch plate without having to do any Mach changes or rewiring between uses. He thought you had finally settled on a 470 ohm 1/4 watt resistor from the input to the +5V terminal of J11 or J12. Is this correct? And do you use a simple touch plate simultaneously with no issues? Do you connect both of these direct to the 126 or is there a buffer/schmitt trigger in between? Thanks
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Post by DaveCVI on Sept 25, 2011 11:33:38 GMT -8
Hi, Pls see below - Dave, I talked to Steve @ PMDX in regards to the 126. I would like use the probe and a touch plate without having to do any Mach changes or rewiring between uses. The PMDX is nice for that as it can do the combining of the multiple probe event devices into the single mach probe input for you in the 126 BoB. He thought you had finally settled on a 470 ohm 1/4 watt resistor from the input to the +5V terminal of J11 or J12. Is this correct? Yes. The resistor goes from +5 to the input pin. The resistor is only needed for the pin you chose for the probe's input line. The resistor compensates for the LED in the probe and keeps the on/off voltages in a good range. FYI - the resistor value was figured out for the Wild horse probe - other probes might need be a bit different value - but the 470 would be a good start point anyhow. If the probe does not have a LED in it that draws power from the input wire, or is one that is only a switch contact internally, then the resistor is not needed. The resistor is also not needed for the Touch plates (they are just 1/2 of a big open switch contact withe tool tip becoming the other half). Do you connect both of these direct to the 126 or is there a buffer/schmitt trigger in between? Thanks I've run the 126 with the probe's input line direct to the 126 pins - that's what Steve and I did all week at the CNC workshup in June - works fine. I don't think and external filter for noise and then a schmitt trigger is needed unless you are really fighting some bad induced noise issues. Dave |
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Post by Fastest1 on Sept 25, 2011 14:01:23 GMT -8
Dave, Thanks so much for the response. It is Arnie's/Wildhorse probe and I have had good success with either it or a touchplate connected individually (on a hobby cnc pro), swapping settings in Mach etc. then I tried to splice into the ground and run both. That just causes chaos. That is what I had read before I purchased the board in regards to both items being connected at once, happy to hear I understood it correctly.
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