Upgrading TRIAC PC Mill

All info relating to the Denford Triac series of CNC milling machines

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Posts: 2
Joined: Fri 26 Apr , 2013 13:08 pm
Hardware/Software: Denford Triac PC Mill (in nice condition) Serial No: EO4177
Date: Nov 1992
Electronics Serial No: 823
Software: FANUC Om (DOS controlled by FANUCMD.exe)

Upgrading TRIAC PC Mill

Post by Geb_Jones » Fri 26 Apr , 2013 13:21 pm

Dear Gents,
Once again another Newbie enters the fold with a few questions (“Oh no” I hear you cry!).

I have recently acquired a Denford Triac PC Mill (in nice condition) which is basically up and running OK. Its credentials are:
Serial No: EO4177
Date: Nov 1992
Electronics Serial No: 823
Software: FANUC Om (DOS controlled by FANUCMD.exe)

It works fine in 2D but I am having a few issues now that I’m trying to move to 3D. 1) I have already reached the practical program size limit of about 58K which is already too small (and even if I upgraded the memory to the maximum of 128K, it will not be enough). 2) The DOS operating system is very clunky. 3) The system is also exhibiting some operational quirks which cause the software to completely bomb out occasionally – back into DOS giving Error No: 128. [This will be the subject of a second query to this Forum a bit later].

Presently I am therefore considering to upgrade the control system to get rid of all these problems. Reading the Forums extensively I see that going to Mach3 or LinuxCNC is a popular route and seems to be a good way to go. So I am left with a number of questions.
1) Do I really need to upgrade the hardware also (for instance with diycnc.co.uk System4 kits or the other Chinese equivalents), as the existing controllers are currently functioning OK in my machine?
2) If I don’t upgrade the controllers – I need to know how to connect say a USB or parallel port Mach3 interface board to the existing Stepper controllers and the Spindle drive. Can anyone out there give me a “definitive connection diagram” to do this (assuming the output of the port controller signals are directly compatible with the inputs to the existing machine controllers)? I have the machine manual but it only gives basic wiring diagrams rather than functional circuit diagrams and signal paths. I would imagine that all the signals I need must terminate in the EuroRack somewhere - so a list of which they are and their function would be a great start.
[I note that this subject has appeared many times on the Forum and I have followed up all leads I can – but nowhere can I find all the info necessary in an understandable form].
3) If the inputs are not directly compatible, can any one give me the signal levels and polarity required by the Denford Board controllers so that I can construct an interface (e.g. TTL active Low etc).
4) Can the existing stepper motors be driven in microsteps to increase resolution or does this require a different stepper control board (and possibly replacement of the motors themselves)?
5) Does the Denford spindle drive work from a standard 0-10V analogue input signal?

It may be that the collective wisdom is that I should upgrade the Denford control motors/boards also. This raises a few more queries:

1) Should I change the motors or just the control boards (also see (4) above).
2) The existing axis motors have (according to the Denford manual) an “undefined type of” torque rating of 7Nm. Most after market upgrade kits (e.g. diycnc.co.uk) offer the NEMA 23 stepper motor as their recommended upgrade component which has a “holding torque” of 3.1Nm. Is this even the important parameter? Is it compatible?? Does anyone have these motors running on a TRIAC – if so are you using the triple-stack Hi-Torque version? What stepper power supply voltage/current are you using? (By the way, in case it helps to visualize the load, I aim to use my mill to create metal molds for carbon fibre components machined from Dural (aluminium) stock).

I realize that I have asked a lot of questions – and many users will have faced the same dilemma before. (There are many threads in the forums which I have studied – but many are difficult to backtrack very far). I would be glad of your feedback and experiences – particularly in the light of more up to date upgrade items that must now be available.

My thanks in advance.

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Re: Upgrading TRIAC PC Mill

Post by Denford Admin » Fri 26 Apr , 2013 14:58 pm

You may have missed these which answer most of your questions, I know it's difficult to see the wood for the trees!
Baldor Nextstep Step and Direction pins - 96way connector
Baldor eurocard schematic and 96 way pinout:
Starmill (Novamill) Baldor Mach3 conversion:
Parker Digiplan stepper drive manuals
Mach3 running unmodified Triac!!!
Help with Triac VMC converting to Mach
Novamill, first time in cnc (Mach conversion)
PKS Digiplan with Mach3

Personally I'd get a new microstepping drive and motor setup and run it from Mach with a decent BOB which has isolated analogue output and protected I/O.
You might have been able to half-step the old drives but 10x microstepping will help a lot with vibration and accuracy on the Triac.
The motors are quite old and will probably work from new microstepping drives but the technology has improved a lot since 1992.
I'd also replace the home datum sensors with switches or proximities that you can plug directly into a BreakoutBoard.
Hopefully those who have done it will add more advice!

Posts: 2
Joined: Fri 26 Apr , 2013 13:08 pm
Hardware/Software: Denford Triac PC Mill (in nice condition) Serial No: EO4177
Date: Nov 1992
Electronics Serial No: 823
Software: FANUC Om (DOS controlled by FANUCMD.exe)

Re: Upgrading TRIAC PC Mill

Post by Geb_Jones » Fri 08 Nov , 2013 15:55 pm

Re my previous email (26th April 2013) - I am indebted to Denford Admin for the excellent pointers given to enable me to update my Triac Mill so that I can run Mach3. I have studied their recommended links and am part way through my conversion.

Initially, I am interfacing a Warp9 Smooth Stepper board with BOB to the existing Denford electronics and later may upgrade the motor drive cards as well (probably with new motors) to enable micro stepping.

Rather than solder wires at various points all over the backplane - I wish to make a replacement plug-in board for the Mint controller containing the smooth Stepper and CNC4PC BOB - using the same 96 way edge connecter used by the Mint board to access most of the input and output signals and doing any 5V to 24V level shifting on this board as well. So far no problem! However there is this mysterious "Custom card" connected to the Mint controller via a ribbon cable and also the back plane.

I cannot find any reference to this board or its function in any of the literature including the circuit diagram manual (I am guessing that amongst other things it may create the 0-10V analogue voltage to the spindle controller ). Can any one give me detailed info on what it does and particularly the functions and pinouts of any of its connections where it plugs into the backplane - as I am guessing I will need some of these signals during my upgrade. Do I need to use any of the functions of this board as part of my upgrade??

A circuit diagram of the backplane (and/or detailed photograhs showing the track layout particularly of the back side would also be a massive help in tracing the signals.

Can you come up trumps again please Admin??


Geb Jones

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Hardware/Software: Triac

Re: Upgrading TRIAC PC Mill

Post by DavidB » Tue 12 Nov , 2013 21:42 pm

I am planning to do a similar conversion using a CNC4PC C11G BOB likely mounted to the box where the current DB25 is and trying to utilise the existing stepper drivers and hardware on my June 1995 Triac PC. I intend to also make plug in replacement boards to get the signals from the BOB to the backplane and provide any level shifting/conversion/isolation. I'll be trying to use the NAMUR proximity sensors used on the original and have traced the simple circuit on the custom card used to convert the current level to suit the Baldor card requirements which will match the C11G by the look of it. I have seen similar circuits on the web. As mentioned earlier the Baldor card details are available on the BB as are the wiring diagrams for the various Triac models and between them a lot can be figured out. I have traced what I require and attached a drawing of the custom card wiring connections I traced. The custom card seems to have been intended to be supplied with AC to provide the various power supply voltages required but in my Triac it is supplied with 24V DC from which all the power supply voltages seem to be derived. In the drawing pins 2z and 4z are connected but I listed them as NC but they seem to connected to one of the main custom card electrolytics so likely a power supply voltage but it only seemed to be connected to the RS card option for the 4th axis so I didn't think I needed it. The Baldor card only supports 3 axes so for 4th axis support the custom card takes in pulse 2 and dir 2 (Z axis) and I presume saves the Z and A axis states and multiplexes between the two to provide support for the 4th axis, not required with the C11G but the output wiring to the backplane slots is required if making interface boards. I have the electronic parts but haven't done the full circuit or board layout yet. Next step is to get the Triac mounted on a stand but have been getting side tracked and so haven't built it yet. Things should progress faster when I have a machine requiring just electronics and software to play with. BTW I was intending to use LinuxCNC for the control as I've been using Linux for years now.
Denford_Triac_custom_card.jpeg (65.09 KiB) Viewed 3199 times

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