Boxford TCL125. (Fresh start )

[depronman]

Have you worked out what voltage the step motors need ?
This for me is the starting point
This will then allow you to select a suitable power DC supply and a pair of stepper drivers
My ORAC needed 70volts so I bought a 68v DC psu and a pair of step motor drivers
The paint was about £45 and the drivers £35ish each
Pair this to a £15 BOB utilising the parallel port a linuxcnc and you are there
Linuxcnc will run quite happily on a very old spec PC either find one on free cycle with a parallel port or get one without and fit one or two pci parallel port cards. eBay at about £7ea also factor in the parallel port cable at about £3. These are 25 pin male to female normally

You need 1 input pin for the eStop
1 for the homing switches
2 for the spindle synchronisation or 3 if you want the spindle to maintain sync when reversion rotation ( I can’t thing of a need for this other than ridged tapping and I can’t think why I would need this on a lathe ) this is know as quadratur (likely spelled wrong)

You can always add another parallel port card for another 14 or so inputs but you will need to work around the option couplers in the BOB
This had be flummoxed for some time as I could never get the second parallel port to work in input mode. It turned out that it was working perfectly in input mode but the BOB was expecting say pin 2 to be an output and as an input pin the option coupler was working the wrong way and not allowing the signal to come through
I only wanted the second parallel port to drive physical buttons so as there was no power to these external buttons I thought sod it and wires the buttons directly to a 25 pin D connector thereby making my own very basis BOB
It’s been working a treat for 12 months

Setting up linuxcnc is not as daunting as it may seem
The DownLoad is copied to a pen drive that you use to boot the PC from. You can trial linuxcnc from it and if you are happy with it you can then install linuxcnc from the pen drive to the pc hard drive. All done in about 20 mins and no scary questions to answer
Using the step configuration wizard in LCNC gets you a basic lathe setup and only takes about 10 mins to produce
It helps if you know your steps per rev on the steppers and the reduction ratio to the lead screws
Take the std pin setup offered by LCNC and wire your stepper drivers accordingly
Pins 2&3 are X 4&5 not used 6&7 are Z
I use pin 10 as eStop
Pin 11 for home switches on x & z
Pins 12 & 13 for the spindle pulse and trigger
Pin 15 is a spare input
Pin 17 for spindle on / off
I also used another output pin for the pwm out that is feed into the lenze isolator board which in turn feeds the lenze to provide swindle speed control. The pin 17 is connected to the BOB relay which is connected to the lenze directly to switch the spindle on and off via m3 / m5. Spindle speed is via m3 with an S positive number say S1000 for 1000 rpm

You need to count the number of slots in the spindle disc and feed this into the calculation in the step confit wizard on the PWM page

Happy to talk you through any of this I can even send you copies of my Hal and ini files

I would use linuxcnc 2.8. It’s just come out but as been in a kind of beta for ages
I have a down load link for mint using LCNC 2.8

Go directly to gmoccapy as the user interface instead of Axis which is the default
Gmoccapy is a far nicer interface and looks like a cnc controller where as Axis looks like a computer screen

I’ve used mach3 and linuxcnc and linuxcnc is head and shoulder better than mach3
It’s also rock solid

I would convert my boxford bid to linuxcnc had I not had invested £200 on a pokeys control board when I thought mach3 was the dogs dangly bits - we all live and learn I guess just an expensive lesson


There looks to be enough room on your 160 to fit the computer motherboard into the electronics area of the machine but you may need to box the PC power supply in a box out side of the machines case
I did this on the ORAC and it makes for a very neat installation, the PC control buttons are brought into the front of the lathe control pane along with control buttons for stop start pause step coolant on off and coolant speed control (I use a peri pump to accurately drip coolant onto the tool)

Hope this gives some idea of what can be done for well under £200 less if you have the PC or can get one from free cycle local car boot sale etc and a little smart shopping

Finally if you are binning the boards removed from the 160 I would like the driver board as a spare for my vmc190 as I chose to reuse the drivers / psu / steppers

Cheers. Paul


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[John11668]

Hi All, and thanks for your inputs
First of all with regard to my old boards . I have had a couple of people declaring an interest in them which causes me a dilemma .
How do I decide who to offer them to. I dont fancy an auction , but would like them to go where they will be of most use .

Can I ask that each of you who are still interested , please PM me and tell me what use you intend to put them to.
Hopefully this will help me to decide . Failing that I will get my wife to pull names from a hat !

[John11668]

From the circuit It seems that the motors require 24 V and on that basis I have bought drivers which range up to 42v

It is my intention to get all the motions functioning, utilising Mach 3 purely to provide jog inputs , after which I will go for a linux option to provide me with a functioning machine.
I am intending to use the existing power source (because it is there) It has outputs of 20v, and 9V which seem after rectification to yield 24v and 12v ( -ve) to the boards but the 12v rectifiers are integral in the board and I cant make out what its capacitor is . Will have to look more closely at it. Clearly I have to add a rectifier if I go this way.

I have a selection of BOBs, one with 0-10v output but only make / break switching at the relay.
I also Have a DIYCNC spindle board which might be suitable





I am hoping that this will give me the the Fwd rev outputs shown in Inee's diagrams but I am not clear on the relay connections shown.
RL1 and RL2 are incorporated in the board , so do I have to insert another relay into the circuit and could the above one fill this role .

Finally with respect to the spindle reversing relay I dont see any numbers on the base . Is there a convention here that I am unaware of ?
It has been working so I am guessing that it will continue to do so one I get the right signals to it .

Thanks again

John

[depronman]

That diy cnc board is the exact board that I have used to provide step/dit from linuxcnc and from it you get a 0 to 10v output which is isolated to feed into the lenze speed controller
You also use the relay to switch the lenze controller
I can provide the lenze connections to the soy bc board if it will help you

Paul


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[John11668]

Soy bc ?
Any info is helpful so yes please

[inee]

Hi john
i have one of those spindle boards, as depronman said it's a good little board.

By spindle reversing relay i take it you mean Rl3 in your Boxford, if so the terminal numbers are printed/stamped into the relay holder ,just above the terminals so either use a mirror or take photos of the wiring and also take some more when you have removed the top set of wires.

Or if i remember tomorrow i can pop a pic of the base up

[John11668]

I think I have sussed the control wires to the relay now Inee, and I havent disturbed any others so hoping it will work when it gets correct inputs .
Will see what happens when I get new power supplies for BOB and The relay board .

Thanks to all for your help,

[John11668]

So being a bit pedantic here in trying to understand the difference between 0v, and Ground?? Remember I am not an electrician.
On the diagram included above, the Small DC voltages are shown as say 12v to 0v. AC supply is L,N,and E, and the 0v is connected back to earth anyway.

Some boards have both 0v and GND suggesting at least a subtle difference , And the TCL 125 control panel is a veritable spaghetti of green and white cables all of which seem to be connected to the metal chassis anyway. Is it OK to connect anything resembling 0v,,GND, and earth to the metal chassis provided that it in turn is securely connected to the incoming Earth conductor ?

I will be adding my new power supplies to my upper deck tomorrow and clearly it would be neater if these could be earthed to the chassis , and where a PSU has connections to L,N,E, and V- ,V+ is there any reason why I cant link E and v- and fasten to the chassis locally to the chassis locally?

[depronman]

HI John,
Equally I'm not an electrician, but I have wired up a few CNC controllers, so please take this as what worked /works for me as against how it should theoretically be done
All of the mains (E) earths should be connected to a single metal bolt which is electrically and mechanically connected to the machines metal case. From an electrical noise and ground loop elimination point it is important to have one single earth point. I Bolt the power supplies to the chassis plate which in theory will cause the PSU to be earthed, but I always connect the E terminal to the single earthing point.
Then connect the maines (L) live and (N) neutral leads to the Power supplies, you would normally take the lives through a fuse / breaker and some sort of contact breaker as appropriate.

On the BOB side I would confirm using a multi meter in ohms setting that the 0v and the GND connections are one and the same. They are not always connected together due to the BOB possibly isolating say the PWM signal from the PC, therefore the GND connection and the PWM 0v connection ideally should NOT be electrically connected. Some better quality BOB are made like this, other cheaper BOB are not like this.

When connecting to the Lenze Speed / Spindle controller for example its VERY important that the 0v of the PWM output is NOT connected to the GND terminals on the BOB or to the machine earth, the reason being the lenze controller needs a 0v to 10v signal to provide the speed control signal (0v = spindle stopped, +10v = spindle at full speed, +5v = spindle at half speed) BUT the Lenze 0v volts terminal is actually at 110v compared to mains earth and mains neutral and for that matter to the PC's ground. It goes without saying that it would be terminal for the BOB and the PC if 110v is applied to the PC ground.
This is the reason why the BOB MUST isolate the PWM 0v from the BOB GRD connections.

My BOB £8 from ebay, very common one with a single relay, does PWM and if used to control a VFD its perfect, however it is NOT suitable for the lenze controller as the 0v PWM on the BOB is electrically connected to the GRN connections on the BOB.
I had to work around this by using a DIYCNC spindle controller board which is feed with Step / Dir from the BOB and a 12V and Grd power feed. From this it generates a 0v to 10v voltage and importantly this is totally isolated from the Gnd & 12v power feed into the board AND also isolated from the Gnd of the BOB
So, in summary this allow the DIYCNC board to provide the 0v to 10v signal into the Lenze controller, which effectively means that the Lenze input voltage will vary between 110v and 120v

On my BOB I found that all of the GND and 0V connections where connected together, this is OK but care needs to be taken with things like Limit Switches to ensure that when connected to the BOB that one side of the limit switch is not connected to earth by virtue of being attached to the machine frame.

Hope that helps, fell free to give me a ring if anything is unclear

Paul

[John11668]

Hi Paul
I had thought that the isolation cad on the lenze controller gave that protection.
If you look at the wiring diagram I inserted earlier in this thread , the 0v connection from the iso board ( term 5) come back to a common 0v buss which picks up the the drivers and rectifiers on its way back to a direct connection to the Mains Earth.

I will be using the Bob which was repaired for me by Doddy which has the facility for a 0-10v signal but only a make/break relay.
Does the DIYCNC spindle board generate its own signal output, so no need to connect the BOB 0-10 signal ? Or might it be better to take the speed regulation signal straight from the BOB and cut out the middle man as it were?