Time to setup my lathe with 7i76e

andypugh wrote:

rodw wrote:

I think that the selector switch is a better option as thats what LinuxCNC expects.

I think using a wafer switch and fixed resistors into an analogue input is fairly cunning. You can have several positions into a single IO pin.
The HAL side can be a set of wcomp components or a lincurve component with the output converted to integer.

wcomp looks interesting and one of them will cover 3 scale ranges which is all a metric machine needs.

One other thought depending on where you locate the MPG wheels is to consider a momentary safety switch. My wireless MPG has one of these and it must be pressed in to enable the jog wheel. It also allows you to select jog mode by referencing the switch input without touching the GUI. If it is likely the MPGs can be bumped, maybe consider this. It would be pretty easy to implement in HAL.

So here I am >>>> kidney stones again = pain == painkillers === totally wasted, that's my life the last 2 days.
Stone/stones have moved a bit so that is positive, just now just tired but no pain.

This is how I envision the MPG wheels on my lathe.



Z down left and X up right. Rotary switch Off - On (power to MPG's) - X 0.01 - X 0.1 - X 1 = 4 switch steps
CAT6 cable pre wired to front = Z A/B + X A/B = 4 leads 5VDC = 2 leads leaves me with 2 wires for switch position = 3 resistor values!
Have also been thinking of adding X 0.05 and X 0.5 = 6 switch steps possibly even X 2 = 7 steps
So this way only 1 analog input is used, how to solve this in HAL?

Is there a way to disable these 2 MPG's when code is running if forgotten to switch Off ?


Cheers
Bengt

tecno wrote:

Is there a way to disable these 2 MPG's when code is running if forgotten to switch Off ?

There should be no need to worry. Jogging (using an MPG is still jogging) is disabled when Linuxcnc is running code in Auto mode or in while in MDI mode.

Thanks Todd,

So I could leave out the On/Off function then, right?

I'll leave it for Andy to help with the analog input configuration

tecno wrote:

Is there a way to disable these 2 MPG's when code is running if forgotten to switch Off ?
t

The MPG's are disabled when running code. in Gmocappy, they only work if the jogging tab is displayed.

You still may want it. Most of the large industrial machines I've worked with do have some way to toggle on and off the MPG function. (I've never set up or used an MPG for Linuxcnc.)

OK, will have a separate On/Off switch to power MPG's



I have some 1-pole 12-way (restricted to 8) switches that I will use as in PDF.

PCW did say that 5K would be optimal for Analog input so I hope above values are OK.

It think you are setting yourself up for problems.

Read the 7i76e manual again.

The analog inputs have a full scale range of 36.3 volts. Using a 5 volt input is going to limit the resolution to 141 discrete levels out of a possible 1024 (eg 13% of the full scale range) and then you want to split that into 8 ranges....... so it would be easy to get a false reading.

I would use your field power (are you using 24 volts?). This will already be grounded on the 7i76e so the connections will be different.

Connect the 7i76e input to where you show GND and connect the other side (currently going to the input pin) to field power.

Assuming your field power is 24 volts, that will give you 66% of the full scale range so 677 discrete steps to split 8 ways.

Not good to draw when you are having kidney stone problems....... (now one big saw light one hour ago - YEYYY)

You are right = field power is correct. Wlll redraw schematics tomorrow.

The only other feedback I can give after using the 7i76e MPG's is that I doubt you need so many ranges but hey, you might as well add the resistors and then decide.

I am just using 1.0, 0.1 and 0.01 mm jogging and its very quick to touch off the z axis by jogging down until my float switch triggers, then jogging up until it goes out. You should check that you have enough resolution in your motors before trying to set up micron accuracy (0.001mm)