Messages

3771

General Mach Discussion / Re: CS Labs CSMIO/P-A

« on: August 25, 2018, 08:59:27 PM »

Hi,
I've downloaded a copy of the CSMIO/IP-A manual.

I would use the 24V power supplies provided within the servo drives.

You have two servos each with its own 24V supply. It is highly likely that they will be the same but if they are not and you connected them together,
that is 0V to 0V and 24V to 24V and they are not identical they could fight each other, I would not recommend it.

I would instead use the 24V supply from one drive to power one of the photo transistor clusters of the CSMIO and use the second 24V from the other drive
to power a second but separate cluster. From page 27 and 28 if you hook the 0V and 24V outputs of one drive to pins 14 and 1 respectively of the DB25
Output connector of the CSMIO then outputs 0-3 of the CSMIO can signal inputs to the drive. In reality you probably only need one, an enable. You
could use others if you were attempting position or velocity indexing but as you are not the will be three unused outputs in that cluster.

With that arrangement the CSMIO output sources current per page 28. That would hook to the anode of the input photodiode of the drive input and the catode
would hook to 0V of its own drive.

In like fashion the 0V and 24V of the second drive would hook to pins 17 and 4 respectively providing supply for outputs 4-7. One of which would be hooked to
the anode of the input photodiode of your selected input of the drive, the cathode would hook to 0V.

Note that the outputs of the CSMIO are current limited but it looks like the current limit is 250mA, rather too much for a photodiode input. Its likely that the photodiode
input has a current limiting resistor in circuit, if not an external resistor will be required. About 5kOhm with a 24V drive will cause an active photodiode current
of about 4mA which should be enough to reliably signal across the opto barrier and still retain a sufficiently low impedance to not be noise prone.

That arrangement allows the outputs of the CSMIO to signal to the drive inputs.

Now consider the reverse. You will want at least one digital output form the drive, a fault signal. You may in fact want more than one. I have not studied
the Lexium manual but I suspect much like my Allen Bradley servo there are a number of fault conditions which can be signaled independently.
Given that you are using the CSMIO to close the position loop then you will not be concerned with a 'following error' fault from the drive. The other
two commonly signaled faults you may wish to handle separately. 'Over current' has a similar meaning to 'following error', when the commanded position
varies widely from the actual position the servo loop attempts to apply a large correction and correspondingly large current. The second fault is 'overvoltage'
which is a the primary indicator that the commanded deceleration exceeds the drives ability to absorb the braking energy. There will be other faults generated by
the drive including overheat and out of limits if so programmed but they are usually combined into one fault output.

I would again make use of the built in 24V supply of the drive. Using Type 1 logic of the previous pic:
connect the phototransitor collector (drive output) to the cathode of the CSMIO input photodiode, IN0-, pin 14, as an example, and the 24V supply of the drive to the anode
IN0+, pin1 per page 23. It would appear that there is a current limit diode in the input circuit of the CSMIO so you need not concern yourself with an external
resistor. You will have to repeat this, ie two wires to each of the CSMIO inputs you require. Make sure that the supply sourcing the output current is returning to the
same supply. That is do not use the X axis drive to supply output current for a Z axis output.

Craig

3772

General Mach Discussion / Re: can I send axes pulses to MODBUS TCP device ?

« on: August 25, 2018, 05:30:46 PM »

Hi,
I don't think MODBUS will retain accurate timing and therefore the motors will stutter and/or stall.

The step output pulses from a parallel port in default configuration could be up to 25kHz.
Thus in every 10ms period you might have to signal 250 pulses, that's way WAY faster than Mach can generate and
send signals.

There are PLCs which can generate pulse streams if they are provided with P(osition)V(elocity)over T(ime) data. So basically Mach
tells the PLC via MODBUS what the motor is to do and the PLC generates the pulse streams to do it. You might say that the PLC
is a motion controller. To my knowledge such PLCs can handle only one motor at a time, so you would require two PLCs for X and Y.
The downside is that the two motors would not be synchronized together.

What you are trying to achieve is possible, in fact its the leading edge of automation and control engineering.

May I suggest you do some research on EtherCat. It is a TCP communication protocol that can communicate PVT data from a centralized
trajectory planner (Mach/PC) to multiple EtherCat Slaves (EtherCat servo drives) and co-ordinate motion.

While that sounds very promising there are some stumbling blocks. The most widely recognized manufacturer of EtherCat servos/drives is
Yaskawa, ie expensive. If you want to drive steppers then you need an EtherCat slave with a stepper driver......Beckhoff make those but
really expensive.

Even if the expense of the servos and/or drives does not put you off then this will. EtherCat is a realtime communication protocol,
Windows PC's are not. You could use LinuxCNC which is realtime and can be an EtherCat master, or you need a controller like the HiCon or Gallil
in addition to the PC, and the controller  assumes the duties of the realtime EtherCat master, at even more expense.

Do you mind sharing why you want to do this? There maybe some alternatives which would be of use to you but without knowing what you want to achieve
its all guesswork.

Craig

3773

General Mach Discussion / Re: CS Labs CSMIO/P-A

« on: August 25, 2018, 04:56:29 PM »

Hi,
do you have a representative circuit diagram for the inputs and outputs of the CSMIO?

The output of the drive is just an isolated phototransistor. If the emitter is connected to 0V then the collector sinks current
whereas if the collector is connected logic high (24V in your case) then the emitter sources current. Easy and flexible.

The choice of which and whether you use the internal supply is going to be determined by the CSMIO, the drive can mange
just about any configuration.

Craig

3774

General Mach Discussion / Re: How fast can you send G90 and get accurate feedback on the current XYZ position

« on: August 24, 2018, 10:43:04 PM »

Hi Sam,

My guess is that it was actually 23us of jitter

Yeah, that sounds better, I came away from watching that video a bit confused.....23ms jitter is rubbish, Mach4 and my ESS can beat that hands down
and even that is not fast enough for many applications.

Thanks for your reply.

My problem is that I don't really know anything about Linux thus much of the capabilities and flexibility of Linux and therefore LinuxCNC are beyond me.
I have a spare laptop and could be persuaded to install a Linux distro 'just for fun'.

Craig

3775

General Mach Discussion / Re: How fast can you send G90 and get accurate feedback on the current XYZ position

« on: August 24, 2018, 10:15:52 PM »

Hi skunkworks,
my apologies to OP if this is off topic.

skunkworks:
I have seen that Linux CNC uses RealTime Extensions to achieve realtime performance. I also saw a video where at the end of the
installation of the Linux distro (with the RTE's) to test the realtime performance. The video of the system under test reported
'a jitter of 23ms'. This was reported to be normal and adequate for LinuxCNC.

Can you clarify what it was that I saw, I would not have thought that a communication loop which included 23ms jitter would have been
anything like sufficient for a realtime feedback controller?

Craig

3776

General Mach Discussion / Re: help with mach3

« on: August 24, 2018, 08:33:59 PM »

Hi Peter,
gotta luv it when a plan comes together!

But 'Don't worry there is still plenty of time....for it to all crap out yet!' 

Craig

3777

General Mach Discussion / Re: What kind of bit/end mill should I be using?

« on: August 24, 2018, 08:24:26 PM »

Hi,
the real killer for aluminum cutting tools is heat.....and I don't mean necessarily heat of the tool or workpiece. Its more about
the heat of the chips.

There are some excellent videos on you-tube about chip formation, every mechanical engineer has to be intimately familiar with this process
AND the calculations that result. I'm only very fair with the calculations myself.

Amongst the objectives of forming a chip is to have the energy of the shearing work to enter the chip rather than the workpiece or the tool. You'd
say that the chip is 'hot'. You will of course have seen 'blue' hot steel chips forming when drilling steel. The same thing happens with aluminum but
without the change in color. Also the melting point of aluminum is only about 780 C whereas steel is about 1480 C.

If by a combination of heat and pressure aluminum chips adhere to the edge of the tool the energy (heat) required for the now blunt tool, by virtue
of the rounded built up edge, to create fresh chips increases dramatically. This results in now very very hot aluminum chips and will have a great propensity
to stick to the already built up edge. Breakage is now imminent.

It is a similar line of reasoning that recutting chips must be avoided. When an aluminum chip is formed it gets hot, lets say 400C. Should that same chip
get recut by the next flute it will get hotter again....lets say 700 C. At that elevated temperature the likelihood of it sticking to the tool goes up hugely.
Thus if you use means like flood cooling or air to remove the chip from the cutzone, it will still get hot, 400 C, air or coolant doesn't change the physics
of chip formation, but air/flood will prevent the chip from getting recut. If you haven't given some thought to trying flood cooling, think again, and if you
decide you can't do it, think a third time until you do it.

Flood coolant or air will have significance for tool life. Lets say that a new and sharp tool will produce chips of 300 C at normal cutting parameters. As the tool
wears and becomes less sharp the temperature of the chips will go up, lets say to 500 C, at which point they adhere to the tool and that tool is now worn out.
If you have flood cooling or compressed air in operation you may be able to cool the chips to the extent that they do not adhere and can carry on using the tool,
extending its life.

I use very small (0.5mm) and tender two flute carbide endmills to cut a thick (0.42mm) copper layer on a circuit board. Without flood cooling I get about 1/2 hour
life for a tool with decreasing cut quality, burrs etc. WITH flood cooling I get about 10 hours, and MUCH BETTER cut quality.
I have had similar experience in aluminum. At 500m/min surface speed my 3mm two flute endmills will last a few minutes before BUE (built up edge) and
subsequent breakage. WITH flood cooling the same endmills last for hours and NO BUE!!

I know a lot of highly authoritative sources say don't use coolant on aluminum but I have found an immense increase in performance if I do.

Craig

3778

General Mach Discussion / Re: What kind of bit/end mill should I be using?

« on: August 23, 2018, 04:37:06 PM »

Hi,
first indication is cut quality, followed by built-up-edge, followed by breakage.
The last two occur within seconds.

Craig

3779

General Mach Discussion / Re: Help Request.

« on: August 23, 2018, 06:58:41 AM »

Hi,
I live on the opposite side of the globe, I don't know a good UK supplier.

If you are serious about updating you need to decide on an external motion controller, that will determine future development options.

All I know about your machine is that it has a parallel port. Does it have one or two? If it has one then you have 12 outputs and 5 inputs.
If you want/need more you will require a controller with more IO than the equivalent of one port.

Lets assume that you have one port and that is all you require. There are three devices that would be of interest to you, the UC100, the PMDX-411
and the 57CNCd25. All three are good and are very similar to one another. They connect to your PC by USB and have a DB25 socket as output mimicing
one parallel port. You might call them a USB to parallel converter but they have an FPGA inside them which makes them way WAY too clever to be
a converter, they are genuine external motion controllers.
https://www.poscope.com/product/pokeys57cncd25/
http://cncdrive.com/UC100.html
https://www.pmdx.com/PMDX-411
These can be had for about $100 to $120. Beware the Chinese are making UC100 rip-offs and selling them cheap on EBay and Amazon, they don't
work like the real thing. Buy direct from the manufacturer or their nominated distributor or you will get ripped-off every time.

If you want more IO then you need to look at:
https://cncdrive.com/UC300.html
https://warp9td.com/  The ESS is the model of choice
https://www.poscope.com/product/pokeys57cnc/

These three devices have plugins for both Mach3 and Mach4. The UC300, the ESS and the 57CNC have 85, 51 and 57 inputs/output respectively. The UC300
and the 57CNC have some analogue inputs as well for extra flexibility.
http://www.pmdx.com/PMDX-424  Is a good two equiv port (31 inputs/outputs) offering by PMDX but is Mach4 only.

Warp9 Tech Design and PMDX are US companies, CNCDrive is Hungarian and I think PoKeys is UK based.

Thre are a couple of other choices, Vital SyStems (US) HiCon and CSLabs (Poland) CSMIO but they are expensive and I wouldn't recommend the CSMIO for Mach4.
The HiCon is about $600US but very VERY capable, price not withstanding, it is worthy of consideration.
http://www.vitalsystem.com/portal/motion/hicon/hicon_integra/hicon_integra.php

I haven't bothered with any of the cheap Chinese, or even the not so cheap Chinese stuff.

My recommendation is to do some research on these units, decide on one. You could still run your existing copy of Mach3 even on your original PC. Those
could be updated later at your convenience. You will love the wide range of PC's and OS's that will now be very effective PC platforms for Mach. If you choose
from those I've mentioned you could update to Mach4 at a later date.

Craig

3780

General Mach Discussion / Re: Help Request.

« on: August 22, 2018, 05:39:35 PM »

Hi,
the latest version of Mach3 is .062, a bit weird because there is a .066 version as well.
If you have a look under the Help Tab/About you will see the version you are running.
The chances are that its fairly similar to what you what you have because all development
on Mach3 ceased five years ago in favour of Mach4.

I use Mach4 and like it. Its a very different program and a lot of Mach3 users hate....tough...
Mach4 is what it is. If you really like Mach3 stick with it but note it will eventually go obsolete.

If you want to avoid a parallel port you will require an external motion controller like a SmoothStepper
or a UC300. There are plenty of cheap Chinese ones but they often don't work well and you won't get
much help with them. If you want one of those ....good luck. A US or European made one range
from about $120 upwards with a SmoothStepper ( ESS by Warp9 Tech Design) about $190US, and upwards.
Such a device (external motion controller) will allow you to use just about any PC you want including
laptops and 64 bit Windows OS's like Windows 10.

Craig