Churchill Computurn 290 retrofit (again)

[Hood]

This control has M41-M44 to choose the gear and you also have to call the M3.
Not tested to see what will happen if I call a speed higher than the allowable speed in the gear range. Whether the control will throw a warning then stop or just limit the speed I don't know. I will have a go when I get home and see.

 

[Hood]

Got the ladder done the right way round and added more I/O. Most of this is just straight through as basically it is just a means of converting the I/O to suit the sourcing or sinking nature of the respective inputs or outputs of the controller and the drives.
I have a spare PLC here so I will, at some point soon, load it into the PLC and hook it up and see if things look ok.

I also tested out the spindle outputs by commanding a speed greater than the gear and there are no warnings or faults, it just puts out the 10v and as I change up the gears without changing the called speed it starts to drop the voltage when it is in a gear that suits the called rpm. So it looks like it should be fine, especially as lathe programming is done in feed per rev and the control does seem to be constantly checking the spindle encoder and thus even if I call 1000rpm but I am only in a gear that max's out at 500 then it should still feed at the correct rate.

 

[Hood]

It has been over 5 years since I did any real ladder logic on the PLC so it has taken me a while to get back into the swing of it even for something simple like this.
I have now loaded the ladder to the PLC, connected the M5 and S01-S04 outputs from the control to the PLC's inputs and ran some MDI code with the 4 gear changes and then the M5 (spindle stop) at the end and it is working just as it should.

 

[awemawson]

The ladder monitoring facility is very handy isn't it !

Having unravelled the Siemens PLC built into the Siemens 820T control in my Beaver using an ancient copy of 'STEP5' (*) I can now monitor things in real time, and it is a huge help in fault finding.


(* STEP5 only runs under Win XP and earlier !!)

 

[HughF]

I really should start playing with PLCs, not sure why, but I'm sure I could find a use for them. I'd normally just do-it at the MCU level with an arduino or similar, but the £20 fake mitsubishi PLCs from AliExpress look tempting.

 

[Hood]

The ladder monitoring facility is very handy isn't it !

Having unravelled the Siemens PLC built into the Siemens 820T control in my Beaver using an ancient copy of 'STEP5' (*) I can now monitor things in real time, and it is a huge help in fault finding.


(* STEP5 only runs under Win XP and earlier !!)

Yes, very handy, just a shame you can't get a monitor that is the normal width but 10 monitors deep I kind of did that when I was doing the ladder for the Chirons Toolchange as I was working half blind and trying to work out how all the valves worked, I used two flat screens one above the other so I could see the full section of each toolchange in the ladder, helped quite a bit, it helped me find out why some of the tools weren't working correctly, someone previously had linked together tool arm wiring, not sure why.

I remember Mark McGrath always on about the Step software but don't think he could ever get it working for some reason.

 

[Hood]

I really should start playing with PLCs, not sure why, but I'm sure I could find a use for them. I'd normally just do-it at the MCU level with an arduino or similar, but the £20 fake mitsubishi PLCs from AliExpress look tempting.

I know nothing about Arduino and just slightly more about PLCs but from the little I know it is amazing what you can do, timers, latching etc etc and I have only scraped the very surface as I only learn what I need to get it doing what I want.

 

[awemawson]

I remember Mark McGrath always on about the Step software but don't think he could ever get it working for some reason.

Mark had loads of Siemens stuff as I recall including the Beaver lathe that your friend had. STEP5 is very arcane, but once you get your head round it it's not too bad. Amazingly Siemens couldn't source a copy for me, but gave me a copy of the later STEP7 which turned out not to be backwards compatible. I ended up sourcing it from a dodgy Russian site wearing thick rubber gloves and boiling it thoroughly before loading

 

[Hood]

Ah, maybe that was the problem, he never wore gloves

 

[HughF]

https://www.aliexpress.com/item/PLC...e2-42bd-afa2-961bdaad4382&transAbTest=ae803_3

<£10 delivered... mad... Not sure about the mitsubishi software availability though...

 

[Hood]

https://www.aliexpress.com/item/PLC...e2-42bd-afa2-961bdaad4382&transAbTest=ae803_3

<£10 delivered... mad... Not sure about the mitsubishi software availability though...

Is that actually a PLC or is it just a module?


Edit, just looked up the Mitsubishi manual and the naming convention suggests it is a main unit.

 

[MattH]

https://www.aliexpress.com/item/PLC...e2-42bd-afa2-961bdaad4382&transAbTest=ae803_3

<£10 delivered... mad... Not sure about the mitsubishi software availability though...

I’ve got a small Mitsubishi PLC I had off Delayd (I think). Going to use it to control the ATC on my next router build. You’ll have to come and help me with the toolchange Marco and ladder logic. FYI I have the Mitsubishi software.

 

[Hood]

Now that I am using the PLC I can do the External/Internal chucking switching without having to use stand alone double pole relay.
Here is all I need in the ladder.

Because the control will only allow the spindle to start if the chuck has clamped inwards (M10) then I had planned on using relays to invert the signals if I pressed a button on the panel and that way the chuck would move outwards to grip but the control would think it was gripping internally. My chuck only needs a momentary signal in either direction for chucking but I have extended the time in the parameters so that it is easier picked up in the video.

 

[HughF]

Is that actually a PLC or is it just a module?


Edit, just looked up the Mitsubishi manual and the naming convention suggests it is a main unit.

Yep, it's a complete fake Mitsubishi...

 

[Hood]

Could be quite good for a retrofit such as the one I am doing as they are cheaper than a single finder style relay and can be configured to do much more. I have never looked at how to programme them but if the software is available it might be worth getting one to try out,

 

[daleyd]

I’ve got a small Mitsubishi PLC I had off Delayd (I think). Going to use it to control the ATC on my next router build. You’ll have to come and help me with the toolchange Marco and ladder logic. FYI I have the Mitsubishi software.

Yeah that was me I can help out with Mitsubishi software (an older version so no good for their later models) if anyone needs it.

 

[Hood]

I seemed to have an issue with the spindle signal (M3) being switched off momentarily whilst changing gears. There is a setting in the controls parameters to keep the spindle switched on but it doesn't seem to be working correctly.
The solution was fairly simple now that I am using the PLC for some of the I/O, I just set a 1/2 second delay off timer into the PLC for the M3 output and the spindle seems to be doing as I want.
In the video you can see the M3 Input (X16) switch off when the gears change but the M3 Output (Y16) stays on until the end when it should switch off.

 

[Hood]

Yeah that was me I can help out with Mitsubishi software (an older version so no good for their later models) if anyone needs it.

Would it work for the ones that @HughF linked to ?

 

[daleyd]

Would it work for the ones that @HughF linked to ?

Not sure, I’ll have a look over the weekend and let you know

 

[Hood]

Not sure, I’ll have a look over the weekend and let you know

Thanks.