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Messages - Jeff_Birt

611
General Mach Discussion / Re: Spindle Control Pins
« on: May 14, 2010, 11:37:19 PM »
Uh, yes just don't configure the spindle as PWM control :) Then set up the correct output to use for M3 (spindle on) for the relay. I would suggest taking a look at the Mach manual to get a good overview of how to configure things.

612
SmoothStepper USB / Re: SS Locking up mach3
« on: May 13, 2010, 10:19:09 PM »
Make sure to use the latest version of Mach, the SmoothStepper driver and SmoothStepper plug-in. a few versions back there was a change in Mach that required a change in the SS plug-in. This means you can mix and match older versions of Mach with the newer versions the SmoothStepper plug-in or vise versa.

I would also suggest trying things out with a fresh new profile to make sure you don't have some goofy setting has crept in.

613
SmoothStepper USB / Re: SS Locking up mach3
« on: May 13, 2010, 04:28:39 PM »
Well, what is the status of the three LEDs on the SmoothStepper? Have you tried a new USB cable?

614
General Mach Discussion / Re: charge pump
« on: May 05, 2010, 03:26:20 PM »
A watchdog timer is a HARDWARE device, the chargepump signal is software driven and there is no guarantee that just because it is present that Mach is working right. At  most it means that the parallel port driver is functioning to the point that the signal can by output.

Using it as a supplementary condition is not a problem, using the EStop input to Mach and the chargepump signal as the only safety circuit is a problem. Some people think that a EStop consistes of a switch input into Mach and Mach then turning off the chargepump and their BOB sensing the chargepump dropping out and cutting out a relay; that is NOT a safety circuit.

615
General Mach Discussion / Re: charge pump
« on: May 05, 2010, 12:44:20 PM »
The problem is that the chargepump signal does not guarantee anything other than Mach did start up and that the part of the parallel port driver that sends out the chargepump signal is working. It cannot guaruntee that your of Mach is working properly.

As Hood says the problem is that some folks thing that Mach and the chargepump signal are the safety devices. (Generally speaking)A Estop chain should not depend on your PC, Mach or any other piece of circuitry working right in order to function properly.

616
Quote
Can a 950 ozin stepper be run from a G540? would have thought the current requirements would have been too much to use the full torque potential of the stepper.

That was my first reaction too, when Chris said that Gecko recommended a G540 to him. Then as I researched the original controller/stepper driver he had I realized that the G540 was heaps a lot better then the OEM stuff. As I recall the motor was already wired in series with a resulting current requirement that fell within the G540's range. You cannot get the maximum performance out of the stepper as if you could as if it were wired in parallel with a higher current driver or with a higher driving voltage but it does provide all the power needed for the application.

I just thought the design was interesting and a but unusual, but it seems to work well. Since we typically get all worked up about getting every last drop of performance out of a stepper motor it is kind of interesting to see a design that 'under drives' a large stepper to provide the power needed for the application with a more modest driver.

617
Hood, Chris's router is a quite interesting commercial built unit. The X-axis is driven by one humongous 950 oz-in (as I recall) stepper through a belt reduction, sent to both sides of the gantry with a cross shaft which has timing pulleys fixed to the ends that drive fixed (wide) timing belts. It pulls itself along the belt. Consequently the steps/unit is quite low but the big stepper has lots of torque at those low speeds.

Chris says the Y-axis was cutting long, he recalibrated the steps/unit for each axis with the Mach axis calibration tool and it is coming out quite close now. I'm anxious to see how things go when he gets his spindle remounted.

618
Just had another thought. You might check both the X and Y axis for backlash. If you have a lot of backlash you can get interesting results at times. Do you see any stair stepping on areas where you have taken multiple passes to cut all the way through the stock?

619
I just noticed you posted this here too Chris.

Since I'm not a member of the Vectric forum where he posted it first I'll copy my reply email here as it does contain some good troubleshooting steps.

Quote
Hmm…problems like this can be tough as you have to find a way to track the issue to the machine or GCode. Since it sounds like it was consistently scaling everything in the Y-axis, instead of only screwing up one place (hesitating in one place), it is probably not an issue with loosing steps or something mechanical. That would leave a configuration problem (Mach) or a GCode problem.

Is it something you can replicate easily with a simpler drawing? If you start the router at 0,0 and then jog or use the MDI line to move the Y-axis close to the full range of travel does it go the right distance? If you can post the file/gcode on the Vectirc forum I bet they can go through it and see if there is a problem there.

I would probably try testing the router with a very simple gcode program, something that just made it do a series of rectangles and return to 0,0. If it returns to 0,0 then mechanically your probably in good shape and it is more likely a gcode issue.

620
General Mach Discussion / Re: Z-axis Auto zero wiring
« on: April 30, 2010, 12:09:26 AM »
OK, 'ground' is not 'ground'. By that I mean that DC Common is not the same thing as AC (earth)ground. What you need to do in a general sense is complete a circuit between the DC Common and the input pin. Most input pins are pulled HI, on the circuit board they have a resistor that is connected between the pin and the +V of the board. When you connect DC Common to the pin you pull the pin LOW and activate the input. This is also called an active low input.

Some BOBs are active HI, and the CNC4PC boards typically are this way. That means the inputs are pulled to DC Common with a resistor and you need to connect the boards +V to the pin and activate the input.

You'll have to look at the manual for your BOB and find out what type of inputs it has then you'll know how to wire it. One word of warning if your machine is (earth)grounded do not attached a clip lead which is wired to the +V of your board to it or you'll short it out as your DC power supply's DC Common (negative side) is likely bonded to (earth)ground.