Rods "Spaceship" Scratch built Plasma Cutter build
05 Jan 2017 02:14 #85266
by rodw
Darn, I forgot about those. I missed an ideal excuse to buy one of them and I was there today
www.machineryhouse.com.au/T0119
I've always been a bit put off by the magnetic base as msot of my machining is in aluminium. I might change my laser order now.
I do have a good set of Dormer machine taps which have been very useful my cordless drill through this project.
Replied by rodw on topic Rods "Spaceship" Scratch built Plasma Cutter build
For much less than $400 you can buy something like: www.grizzly.com/products/Hand-Tapping-Ma...m_source=grizzly.com and you have a useful tool when you are finished.
Darn, I forgot about those. I missed an ideal excuse to buy one of them and I was there today
www.machineryhouse.com.au/T0119
I've always been a bit put off by the magnetic base as msot of my machining is in aluminium. I might change my laser order now.
I do have a good set of Dormer machine taps which have been very useful my cordless drill through this project.
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05 Jan 2017 11:23 #85278
by rodw
Replied by rodw on topic Rods "Spaceship" Scratch built Plasma Cutter build
Well, I made 3 trips to Machinery House today. One to buy a bandsaw blade for work, then back to pick it up from their warehouse across the road from the showroom becasue my desire for coffee resulted in temporary amnesia and the third to collect the tool that Andy suggested I get that I had bought online. Of course they waited until I got home before they sent me an email telling me it was ready for collection!
It says it goes from M4 to M12. Most of the holes I need to tap are M6 and the tap is buried pretty deep once installed
I also picked up a filter for the plasma air supply.
When I got home, I found that the slow boat from China had arrived while I was away and the connector for the plasma cutter cable at the control box end had arrived.
Its a pretty good match for the one that came with my plasma cutter shown on the right.
Drat, hit, the dreaded link limit again. to be continued...
It says it goes from M4 to M12. Most of the holes I need to tap are M6 and the tap is buried pretty deep once installed
I also picked up a filter for the plasma air supply.
When I got home, I found that the slow boat from China had arrived while I was away and the connector for the plasma cutter cable at the control box end had arrived.
Its a pretty good match for the one that came with my plasma cutter shown on the right.
Drat, hit, the dreaded link limit again. to be continued...
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05 Jan 2017 11:23 - 05 Jan 2017 21:10 #85279
by rodw
Replied by rodw on topic Rods "Spaceship" Scratch built Plasma Cutter build
But back onto LinuxCNC, I promised I'd show document how I got an MPG running on the 7i76e. Lets start with the scale selector. I knew I need a 2 bit binary output but I've only ever made them in software before so I asked a friend what to get and he said to get one of
these from Jaycar
. That looked right to me so I grabbed one as I was close to one of their shops.
There were 3 outputs in the centre of the switch (A, B & C). We only need two of these so I picked A & B. But it really did my head in trying to work out how to use it in the absence of documentation. After a while with a multimeter I worked out which wire went where but I still could not work it out. Then I decided I needed to build a truth table showing the binary logic required:
And work out what wires were required to be live where ever there was a 1. My switch pinout said I needed to make pins 3, 4, 6 and 8 live so I tied them together with a yellow wire attached to +24v and an orange and green wire on the centre inputs going to the mux4 pins.
I made a bracket for the 100PPR encoder wheel from some scrap angle iron so it would not short out
The wiring was pretty simple
I stole some 5 volt power from one of the stepper power pins.
Encode A connects to TB3.16
Encoder B connects to TB3.17
I did run into trouble until I found a post from PCW which said if you are using a separate 5V power supply like I am, you needed to tie the 24 volt and 5 volt pin Grounds together. Eg. Connect TB1.1 to TB2.23. But if you follow this wiring schematic , you won't need to do this
As the 7i76e has 2 encoder inputs, I figured I'd use separate encoders for the X & Y axis.
Some of the examples I had seen used the -not signal from an unused input for the encoder enable inut but this looked a bit dodgy to me. Why not simply OR the 2 encoder input pins together and use the output from that as the enable signal? By doing that , the encode will be disabled when the scale switch is at position 0 and enabled at any of the scale settings. Nice and clean!
Here is what the HAL file looks like:
This is set up for a metric machine and the scale is 1mm, 0.1mm and 0.01mm. If you find the scale is reversed, it is becasue the pins are mapped in the reverse order. (eg low order pin connected to high order bit). If this happens to you, just edit the pins in this code.
Remember to change this line based on your config. I had already used a few or2'sWell, thats about it for now. The shopping list is becoming very short.
1. 9 core shielded wire for the connection to the plasma power supply now the connector is to hand
2. A 3 stage air filter including a desiccant drier stage I've had my eye on.
3. About 10 metres of 100 x 100 x 5mm SHS for the frame and some other sundry steel.
The main things I have to do in HAL are:
1. All the THC stuff
2. Sort out my stepper drives so they are working on the correct axis
3. Implement Gantry Joint Axis .
4. Get my warning lights working the way I want them to and I'll need some help on that one.
There were 3 outputs in the centre of the switch (A, B & C). We only need two of these so I picked A & B. But it really did my head in trying to work out how to use it in the absence of documentation. After a while with a multimeter I worked out which wire went where but I still could not work it out. Then I decided I needed to build a truth table showing the binary logic required:
Pos A B
0: 0 0
1: 0 1
2: 1 0
3: 1 1And work out what wires were required to be live where ever there was a 1. My switch pinout said I needed to make pins 3, 4, 6 and 8 live so I tied them together with a yellow wire attached to +24v and an orange and green wire on the centre inputs going to the mux4 pins.
I made a bracket for the 100PPR encoder wheel from some scrap angle iron so it would not short out
The wiring was pretty simple
I stole some 5 volt power from one of the stepper power pins.
Encode A connects to TB3.16
Encoder B connects to TB3.17
I did run into trouble until I found a post from PCW which said if you are using a separate 5V power supply like I am, you needed to tie the 24 volt and 5 volt pin Grounds together. Eg. Connect TB1.1 to TB2.23. But if you follow this wiring schematic , you won't need to do this
As the 7i76e has 2 encoder inputs, I figured I'd use separate encoders for the X & Y axis.
Some of the examples I had seen used the -not signal from an unused input for the encoder enable inut but this looked a bit dodgy to me. Why not simply OR the 2 encoder input pins together and use the output from that as the enable signal? By doing that , the encode will be disabled when the scale switch is at position 0 and enabled at any of the scale settings. Nice and clean!
Here is what the HAL file looks like:
# Metric units used
loadrt hm2_eth board_ip="10.10.10.10" config="firmware=hm2/7i76/7i76e.BIT num_encoders=1 num_pwmgens=0 num_stepgens=5 sserial_port_0=2xxxx"
loadrt mux4 count=1
addf mux4.0 servo-thread
loadrt or2 count=4
addf or2.3 servo-thread
setp axis.x.jog-vel-mode 0
net x-jog-counter <= hm2_7i76e.0.7i76.0.0.enc0.count
net x-jog-counter => axis.x.jog-counts
net mux-in1 or2.3.in0 <= hm2_7i76e.0.7i76.0.0.input-22 => mux4.0.sel0
net mux-in2 or2.3.in1 <= hm2_7i76e.0.7i76.0.0.input-21 => mux4.0.sel1
net x-jog-enable <= or2.3.out
net x-jog-enable => axis.x.jog-enable
setp mux4.0.in0 0.0
setp mux4.0.in1 1.0
setp mux4.0.in2 0.1
setp mux4.0.in3 0.01
net x-jog-scale mux4.0.out => axis.x.jog-scaleThis is set up for a metric machine and the scale is 1mm, 0.1mm and 0.01mm. If you find the scale is reversed, it is becasue the pins are mapped in the reverse order. (eg low order pin connected to high order bit). If this happens to you, just edit the pins in this code.
net mux-in1 or2.3.in0 <= hm2_7i76e.0.7i76.0.0.input-22 => mux4.0.sel0
net mux-in2 or2.3.in1 <= hm2_7i76e.0.7i76.0.0.input-21 => mux4.0.sel1Remember to change this line based on your config. I had already used a few or2's
loadrt or2 count=41. 9 core shielded wire for the connection to the plasma power supply now the connector is to hand
2. A 3 stage air filter including a desiccant drier stage I've had my eye on.
3. About 10 metres of 100 x 100 x 5mm SHS for the frame and some other sundry steel.
The main things I have to do in HAL are:
1. All the THC stuff
2. Sort out my stepper drives so they are working on the correct axis
3. Implement Gantry Joint Axis .
4. Get my warning lights working the way I want them to and I'll need some help on that one.
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05 Jan 2017 21:32 #85305
by rodw
Replied by rodw on topic Rods "Spaceship" Scratch built Plasma Cutter build
Well, it seems people are following along. I had a request overnight to explains some of my HAL code. It just goes to show once you understand something, you gloss over the detail where the hard bits live. This was not meant to be a tutorial, but for the other beginners like me here goes:
You should know by now that loadrt loads a HAL module into your setup
Once you load a module, you usually need to put it in the thread you want to use it in with addf
So you usually need a loadrt and an addf statement before you can use it.
Some HAL modules need you to set a parameter to a given value. you use setp to do that.
With some modules (like or.2), you may use them in multiple places so you need to add a count parameter. I've already got 3 or2 statements in use so I added one more here
Real computers count starting from 0. Just ask any assembly language or C programmer. Once you start counting from 0, a lot of things become a lot easier. So HAL numbers each of the statements as or2.0, or2.1, or2.2, or2.3. As this is the 4th or i've added, I am using or2.3.
But more importantly, because I am using a 7i76e, I need to load the mesa driver hm2_eth.
pncconf makes a valiant effort at making this statement but you probably need to tell it the ip address its installed on. If you read the documentation, you need to place the driver in mode 2. This is the bit that does that sserial_port_0=2xxxx. I found this example on the forum here so I copied it. Don't ask me what the other statements do.
I'm using master branch to get the gantry joint axis feature and I think this has meant some code has changed as the axis module now has axis.x, axis.y etc instead of axis.0, axis.1 etc. So lets look at the next snippet which just sets up some defaults.
The jog-vel-mode parameter can be either 0 or 1. I've set it to 0 so that a given jog step completes. Using a 1 here means that motion stops as soon as you stop turning the wheel.
The next 2 lines read the 7i76e enc0.count and sends it to axis X so that HAL knows which axis to move. You can fold this up onto one line but I broke it up for ease of reading (so try to do this yourself as a training exercise. I did.)
So lets deal with the scale selection. To conserve pins most examples use the mux4 hal component and I realised I left these lines out of my example to load it (now corrected)
This conserves pins once you can work out how to wire in a binary coded switch
these next lines do 3 things. They load the value of the input pins (I'm using 21 & 22) used by the selector switch into a variable I created but along the way, it also loads the value of these pins into an or2 statement. They also send the pin values to our mux4 component inputs.
I think you could break these up onto more lines to make it easier to read so try doing that as a learning exercise.
Before an axis can be jogged, it needs to be enabled using x-jog-enable and that is the purpose of my or.2 output. It will be true (1) whenever a scale is selected with the switch and 0 when the switch is in the off position
Now we need to set the scale according to the position table I documented in the previous post using setp.
You will need to alter the scale values if your machine is using inches.
And now finally tell axis.x which scale to use
So there you have it. A working single axis MPG handwheel using the Mesa ENC0 input and a scale selector switch.
I think Andy said somewhere once that this stuff is hard becasue it really is hard but I hope that this explains whats going on.
You should know by now that loadrt loads a HAL module into your setup
Once you load a module, you usually need to put it in the thread you want to use it in with addf
So you usually need a loadrt and an addf statement before you can use it.
Some HAL modules need you to set a parameter to a given value. you use setp to do that.
With some modules (like or.2), you may use them in multiple places so you need to add a count parameter. I've already got 3 or2 statements in use so I added one more here
loadrt or2 count=4But more importantly, because I am using a 7i76e, I need to load the mesa driver hm2_eth.
loadrt hm2_eth board_ip="10.10.10.10" config="firmware=hm2/7i76/7i76e.BIT num_encoders=1 num_pwmgens=0 num_stepgens=5 sserial_port_0=2xxxx" pncconf makes a valiant effort at making this statement but you probably need to tell it the ip address its installed on. If you read the documentation, you need to place the driver in mode 2. This is the bit that does that sserial_port_0=2xxxx. I found this example on the forum here so I copied it. Don't ask me what the other statements do.
I'm using master branch to get the gantry joint axis feature and I think this has meant some code has changed as the axis module now has axis.x, axis.y etc instead of axis.0, axis.1 etc. So lets look at the next snippet which just sets up some defaults.
setp axis.x.jog-vel-mode 0
net x-jog-counter <= hm2_7i76e.0.7i76.0.0.enc0.count
net x-jog-counter => axis.x.jog-countsThe jog-vel-mode parameter can be either 0 or 1. I've set it to 0 so that a given jog step completes. Using a 1 here means that motion stops as soon as you stop turning the wheel.
The next 2 lines read the 7i76e enc0.count and sends it to axis X so that HAL knows which axis to move. You can fold this up onto one line but I broke it up for ease of reading (so try to do this yourself as a training exercise. I did.)
So lets deal with the scale selection. To conserve pins most examples use the mux4 hal component and I realised I left these lines out of my example to load it (now corrected)
loadrt mux4 count=1
addf mux4.0 servo-threadThis conserves pins once you can work out how to wire in a binary coded switch
these next lines do 3 things. They load the value of the input pins (I'm using 21 & 22) used by the selector switch into a variable I created but along the way, it also loads the value of these pins into an or2 statement. They also send the pin values to our mux4 component inputs.
net mux-in1 or2.3.in0 <= hm2_7i76e.0.7i76.0.0.input-22 => mux4.0.sel0
net mux-in2 or2.3.in1 <= hm2_7i76e.0.7i76.0.0.input-21 => mux4.0.sel1I think you could break these up onto more lines to make it easier to read so try doing that as a learning exercise.
Before an axis can be jogged, it needs to be enabled using x-jog-enable and that is the purpose of my or.2 output. It will be true (1) whenever a scale is selected with the switch and 0 when the switch is in the off position
net x-jog-enable <= or2.3.out
net x-jog-enable => axis.x.jog-enableNow we need to set the scale according to the position table I documented in the previous post using setp.
# jog scale for each switch position in mm
setp mux4.0.in0 0.0
setp mux4.0.in1 1.0
setp mux4.0.in2 0.1
setp mux4.0.in3 0.01And now finally tell axis.x which scale to use
net x-jog-scale mux4.0.out => axis.x.jog-scaleSo there you have it. A working single axis MPG handwheel using the Mesa ENC0 input and a scale selector switch.
I think Andy said somewhere once that this stuff is hard becasue it really is hard but I hope that this explains whats going on.
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07 Jan 2017 00:44 - 07 Jan 2017 00:47 #85378
by rodw
Replied by rodw on topic Rods "Spaceship" Scratch built Plasma Cutter build
One of the things I wanted to do is to get some warning lights enabled as a traffic light system. After a fruitless afternoon yesterday, Todd wrote the code out for me on this thread
forum.linuxcnc.org/24-hal-components/321...green?start=10#85375
Of course, it is never as simple as it seems to implement a code example in Hal.
This is what Todd gave me
And becasue I wanted to also keep the functionality of the run/step hold/resume buttons from this example
forum.linuxcnc.org/47-hal-examples/13201...-hold-resume-buttons
This is what I came up with
And here it is in action
Ultimately, I had in mind to add a stack light on top of the gantry so the machine status can be seen at a glance across the room. Something like this one (when I can find one with LED's in it/
www.ebay.com.au/itm/DC-24V-3-Bulbs-Red-G...2:g:lMQAAOSw8w1YAqxg
forum.linuxcnc.org/24-hal-components/321...green?start=10#85375
Of course, it is never as simple as it seems to implement a code example in Hal.
This is what Todd gave me
loadrt and2 count=2
loadrt xor2 count=1
loadrt siggen num_chan=1
addf and2.0 servo-thread
addf and2.1 servo-thread
addf xor2.0 servo-thread
addf siggen.0.update servo-thread
setp siggen.0.frequency 2
#Yellow Light
net yellow-in1 <= halui.machine.is-on => and2.0.in0
net yellow-in2 <= halui.program.is-idle => and2.0.in1
net yellow-out <= and2.0.out
net yellow-out => hm2_7i76e.0.7i76.0.0.output-01
#Green Light
net green-in1 <= halui.program.is-running => xor2.0.in0
net green-in2 <= halui.program.is-paused => and2.1.in1
net flash <= siggen.0.clock => and2.1.in0
net green-flash <= and2.1.out => xor2.0.in1
net green-on <= xor2.0.out => hm2_7i76e.0.7i76.0.0.output-02
#Red Light
net red-on <= halui.estop.is-activated => hm2_7i76e.0.7i76.0.0.output-00And becasue I wanted to also keep the functionality of the run/step hold/resume buttons from this example
forum.linuxcnc.org/47-hal-examples/13201...-hold-resume-buttons
This is what I came up with
loadrt xor2 count=1
loadrt siggen num_chan=1
loadrt and2 count=6
addf and2.0 servo-thread
addf and2.1 servo-thread
addf and2.2 servo-thread
addf and2.3 servo-thread
addf and2.4 servo-thread
addf and2.5 servo-thread
addf xor2.0 servo-thread
# External Program Pause/Resume and Run/Step Buttons
# Pause/Resume Section
net pause-resume-btn and2.0.in0 and2.1.in0 <= hm2_7i76e.0.7i76.0.0.input-02-not
net pause-on toggle2nist.0.is-on <= and2.0.in1 <= and2.3.in1 <= and2.5.in1 <= halui.program.is-paused
net run-on and2.1.in1 <= xor2.0.in0 <= halui.program.is-running
net pause-sig or2.0.in0 <= and2.0.out
net resume-sig or2.0.in1 <= and2.1.out
net toggle-ok toggle.0.in <= or2.0.out
net togglesig toggle2nist.0.in <= toggle.0.out
net toggleon halui.program.pause <= toggle2nist.0.on
net toggleoff halui.program.resume <= toggle2nist.0.off
# Run/Step Section
net run-step-btn and2.2.in0 and2.3.in0 <= hm2_7i76e.0.7i76.0.0.input-01
net idle-on and2.2.in1 <= and2.4.in1 <= halui.program.is-idle
# net pause.on and2.3.in1 <= halui.program.is-paused
# and2.3.in1 was added in the net pause-on statement in Pause/Resume Section
net run-sig halui.mode.auto halui.program.run <= and2.2.out
net step-sig halui.program.step <= and2.3.out
net estop-out estop-latch.0.fault-out
# --- RED, GREEN AMBER WARNING LIGHTS ---
#Yellow Light
net yellow-in1 <= halui.machine.is-on => and2.4.in0
net idle-on <= halui.program.is-idle => and2.4.in1
net yellow-out <= and2.4.out
net yellow-out => hm2_7i76e.0.7i76.0.0.output-01
#Green Light
net flash <= siggen.0.clock => and2.5.in0
net green-flash <= and2.5.out => xor2.0.in1
net green-on <= xor2.0.out => hm2_7i76e.0.7i76.0.0.output-02
#Red Light
net estop-out hm2_7i76e.0.7i76.0.0.output-00
And here it is in action
Ultimately, I had in mind to add a stack light on top of the gantry so the machine status can be seen at a glance across the room. Something like this one (when I can find one with LED's in it/
www.ebay.com.au/itm/DC-24V-3-Bulbs-Red-G...2:g:lMQAAOSw8w1YAqxg
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