MULTICAM M1 ELECTRONICS UPGRADE

[CNCMAN172]

Nice Sign, what did you create the sign in Artcam or something else.

Russ

[pari]

You blew 3 out of 4 of the stepper drives on a G540? That must be some sort of record! What did Peter say?

Yes, I would most emphatically shield the motor cables!!!

I used soldered 9-pin D connectors for everything, but the Molex connectors you show should be fine for the steppers. Just make sure you do the crimps well.

Cheers
Roger

Peter didn't say much, what could he say really without calling me a F--ing idiot!
It was a very expensive mistake and I still don't really know where I went wrong as the only drive that didn't blow was the one I was testing to try and get connected properly.
Any hoo, over the last couple of days I've wired the 3 stepper axis with new 4 core shielded cable and got them working. This is all a big learning curve for me. I messed around with some crappy connectors I bought from J-Car. They were crap. Then it occurred to me to keep the old connectors and just splice onto the end of them and insulate very well with heat shrink. It all looks in order and neat now.
Next I have to figure out how to connect the existing Z top limit switch and after that install 2 more switches I got for homing. But at least everything is working now and I will start re-assembling the gantry soon as I figure out were the wires need to pass through for the homing switches. I'm feeling more optimistic about it being completed successfully than I did a couple of weeks ago!!


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[RCaffin]

Chuckle.
The G540 is all very well, but the G203V single stepper drive comes with a guarrantee that you cannot blow it up. If you search here on CNCZone you may find a thread where the owner of Gecko actually challenges 'the world' to blow one up! If it blows up he will repair it for free. My memory is that he did not have to do many repairs. (So I bought one.)
He does draw an exception against covering the PCB with metal swarf. That seems ... reasonable!

Splicing: we have all done that at times. Needs good solder joints, which are not always that easy, but if well done the result can be very neat.

Limit and Homing switches: many do not bother with Homing at all. We just reset the zero to the job each time. Limits switches are a good idea, although some have given lots of trouble. That may have been due to resonance of the internals - or so it seemed to me at the time.

Cheers
Roger

[pari]

Maybe when I get Building another machine I'll consider the G203V....
I just thought I'd put a few images up for any one interested in the progress of this project.
The Z down movement that was reliant on Gravity has had a simple fix with a couple of screws going into T cross bar of the nut. So now it is moved down and up with the lead screw turning.
One image of the spliced and heat shrinked connector and the new 4 core shielded cable and DB9 connector that goes into the new controller.
I have a question. One image above shows the old but effective Z top limit switch. I want to re-use it but it has three wires one being ground. But on the schematics from Peter they show all homing and limit switches wired in series. So what do I do with the ground wire. or do I not worry about it and not connect it to anything?
Having the homing switches is very important to me and a big incentive to doing this upgrade. I think the Z isn't so important maybe but I got use to it with the old system and because there is so little Z height having a soft limit will be use full so I'm not crashing it.

[RCaffin]

Not sure how it was arranged with the 3-wire system. Looks odd at least.
I suggest you simply use the Gnd wire as a 'screen', to reduce noise pickup, and wire the three switches per the diagram from Peter. Mine has the Limit switches all wired in series too.

Cheers
Roger

[pari]

Not sure how it was arranged with the 3-wire system. Looks odd at least.
I suggest you simply use the Gnd wire as a 'screen', to reduce noise pickup, and wire the three switches per the diagram from Peter. Mine has the Limit switches all wired in series too.

Cheers
Roger

What do you mean by 'screen'? Would that be earthing it to something like the control box or CNC frame?
The rest sounds good. Looks like I've figured out where to put the other two switches. Should be pretty tidy once it's done. I bought the cheap Ormon switches from Peter to see how they work but might invest in the sealed ones or proximity sensor at a later date.


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[CNCMAN172]

Pari,

He talking about cables with a copper braided shield, you don't want cable with just a foil shield. The braided copper is good at keeping noise away from the signals. The shield is grounded at the controller end.




Russ

[RCaffin]

As Russ said.
Cheers
Roger

[pari]

Thanks guys, I'll keep it mind when I'm ready to wire the switches in.


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[pari]

I got the axis all moving last evening. The router is basically re-assembled. But today I started to look around mach3. I tried to jog in step mode and the machine is making some horrible screeching noises and lurching. I realised I probably need to do some kind of calibration or motor tuning? The units are also set to inches which confuses me more, can't get my head around inches- seems archaic to me! Can anyone advise. Just a note my machine is run with belts and rack and pinion. The images up top are of the current motor tuning for X axis. The machine seems to jog very smoothly once I turned down the acceleration speed to 2". I'm using a ESS Mach3 profile that Peter sent me.


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[RCaffin]

You probably need to do some tuning odf the PID controls in the drivers. It sounds as though they may be oscillating - never good.

Inches - what are they?
To change units: Config/select units (top of list)/click on mm and then go down to Save Settings and click on that.

Cheers

[pari]

You probably need to do some tuning odf the PID controls in the drivers. It sounds as though they may be oscillating - never good.

Inches - what are they?
To change units: Config/select units (top of list)/click on mm and then go down to Save Settings and click on that.

Cheers

Where do I do that (tune PID control)?
And when I change the units to mm do I need to change all the values that are in the motor tuning section in Mach3?


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[RCaffin]

You tune the PID controls inside the drivers. Nothing to do with the SW in the computer; everything to do with the hardware hung off the motor. There should be a manual with the drivers telling you how.

When you switch to mm from inches, you do not need to touch the drivers. They know absolutely nothing about inches or mm.
I am not sure what you would need to do to the motor settings in Mach3 though. One would HOPE that Mach3 could simply translate the previous imperial values.
Short answer: figure on revisiting the SW tuning, just for safety.

Cheers
Roger

[pari]

You tune the PID controls inside the drivers. Nothing to do with the SW in the computer; everything to do with the hardware hung off the motor. There should be a manual with the drivers telling you how.

When you switch to mm from inches, you do not need to touch the drivers. They know absolutely nothing about inches or mm.
I am not sure what you would need to do to the motor settings in Mach3 though. One would HOPE that Mach3 could simply translate the previous imperial values.
Short answer: figure on revisiting the SW tuning, just for safety.

Cheers
Roger

Well I have the motors tuned and running at last. I must admit I found the whole thing very scary, and probably would still be struggling with it if it wasn't for Peters (Homann) help.
So the next stage of this upgrade is to start wiring the limit switches.
I have a question about this. I will be going to buy my cable this Sunday, probably from J-Car. What kind of wire is normally used, can I just get 2 core grey speaker wire?


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[RCaffin]

Well, that would probably be OK, but ...
First of all, the wires will be carrying something like 5 mA. That is next to nothing, so the llighest copper would do. But there is vibration and rubbing to consider as well, so you don't want something too light.
However, there's a lot of noise around the machine, so it would be nice to use screened 2-core instead of unscreened 2-core.
Jaycar WB1504 looks suitable (on the web site that is). It has a thick PVC jacket.
WB1530 is a screened 2-core microphone cable, which is probably even more robust. A bit more $$ though.
WB1590 is not 'screened' per se, but if you earthed (one end only) two of the four wires it could also do.

Earth the screen at the control end only, NOT at the switch end.

Cheers
Roger

[pari]

Well, that would probably be OK, but ...
First of all, the wires will be carrying something like 5 mA. That is next to nothing, so the llighest copper would do. But there is vibration and rubbing to consider as well, so you don't want something too light.
However, there's a lot of noise around the machine, so it would be nice to use screened 2-core instead of unscreened 2-core.
Jaycar WB1504 looks suitable (on the web site that is). It has a thick PVC jacket.
WB1530 is a screened 2-core microphone cable, which is probably even more robust. A bit more $$ though.
WB1590 is not 'screened' per se, but if you earthed (one end only) two of the four wires it could also do.

Earth the screen at the control end only, NOT at the switch end.

Cheers
Roger

Thanks Roger, I'll take look at the shielded stuff .


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[pari]

I have a few questions, as I don't understand the need for more than one wire If the the limit switches are wired in series. How do you use a a two core wire to wire in series? Or is it you just use one of the wires? Or splice one switch into one of the wires and the other continues on till it's heading out of the final switch and that one is the other side that completes the circuit ( if you know what I mean, probably didn't explain it very well!) And were on the control end does the earth terminate? Does it go into the DB9 connector? Or do I solder a single wire to that and attach it to the CNC frame or the control box? I know, a lot of questions, but I'm a bit clueless with this stuff and am learning from scratch.


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[CNCMAN172]

Pari,
There are several ways to wire limit switches, but most people wire them all in Series with NC contact of limit switches.

Here is a webpage that explains this in detail
Wiring home and limit switches

Keep in mind if you are planning on using the home switches as limit switches you can't wire these in series. But the reason for two wires is you have two contacts on each switch the Common and the NC connection. You could actually loop a single conductor from contact to contact all the way around your machine. Do to noise most people keep these in cables with a copper mesh inside that is grounded at one end to shield these signals from noise. For each higher noise immunity many people have the limit switches all in series that operate a 24V relay where the contacts are used to interface to the BOB (Break Out Board). This ensures that low level noise will not impact the signal which is 24VDC, and the interface to the BOB is very short wires from the relay, one to ground the other to the Limit Switch input pin on the BOB. If you have a controller picked out we can explain exactly what you have to do to get things working correctly.

Russ

[InMesh]

Great explanation, I ran a code about 40 minutes or so and half way through it stopped due to a limit switch trigger ( noise I suspect) I tried a number of things to fix it but again it appeared so now for long complex stuff I have them turned off the table is big enough .all the cables are shielded and ground is good Noise is the killer .

[RCaffin]

Filtering is good. You can add a small capacitor across the switches, or activate the SW filtering in Mach - or both.
Cheers
Roger