resurrecting an old CNC7 system prior to upgrade (K1346B-1)

[MM0TJR]

we have an old YCM knee mill, with 1990s Centroid control system. will post further pics to form into a build thread shortly, meantime I wanted to ask for some basic guidance.
I am electronics technician to an old machinist, and I have carried out repairs to this machine along the way. Unfortunately, there has been a 2-year hiatus in our operation, and in this time the CNC mill has been left to "go cold". Now we are trying to get it going again with a view to upgrading the old control system. Before we commit to upgrade, we want to try to get the machine back the way it was to ensure that there are no other Gotchas.

OK, so first problem was that the DOS PC would not boot. total mechanical hard drive failure.
I had - perhaps not completely - backed up that hard drive a few years ago, so I have been able to repair the DOS machine and now we have a booting system, but the intialisation does not seem to be quite how I remember it: what we remember is, that at some point during the startup of the Centroid software, a large contactor should pull-in and communication with a PLC (?) should be established.
That does not seem to be happening.

I am pretty competent in DOS systems, PLCs and electronics/electricals in general, but my notes on this old project are sadly lacking.

could anyone guide me to a system layout, and general startup notes for this machine?
stuff like - what utilities should be loading in autoexec.bat and/or config.sys, and in what order & why..

the backup that I took of the hard drive for some reason does not include autoexec.bat nor config.sys and I cannot work out why this is. I took this backup before setting up a DOS network client in order to do convenient file transfers, and I certainly used autoexec.bat for that.

thanks in advance
Tris & Derek - Northern Scotland UK

[cncsnw]

Most of the interesting things will be in the CNC7 folder.

Typically, AUTOEXEC.BAT changes to the CNC7 directory, then runs CNC7M4.BAT. CNC7M4.BAT runs CNC7.EXE (or CNC7M.EXE, depending on your software version).

The emergency stop contactor will only pull in when the emergency stop button is released and the servo drive is in a non-fault condition.
The servo drive will only go to a non-fault condition after the CNC7 software begins initializing the CPU7 board, so that the CPU7 begins communicating with the servo drive over the DATA and SYNC optical fibers.

Do you see the CNC7 software begin to run?
Does it say "Initializing CPU7" on the screen?
Does it continue to a screen with a blank DRO display, a status window and message box in the upper right, and a "Machine home not set" message in the middle of the screen?

[MM0TJR]

cncsnw - thanks so much, this jogs my memory!
We now seem to have got the machine back to a functional state with all command & control basically functional. Im not sure exactly what I was doing wrong the first time round, apart from I had a standard PC keyboard plugged into the PC, and this time I had the proprietary control keyboard connected. I can't see why this would be a problem, the Centroid control board surely just emulates the commands from a normal kbd but perhaps I am missing something here.
Anyway, I have taken hopefully comprehensive photographs & documentation. We would be very interested in advice on the best upgrade path here, to bring us into the modern world. The existing control is reliant on various arcane modules, probably the least replacable of which is the 486 motherboard & DOS system.

Videos of the control system booting, homing & demonstrating are here:
- start from cold, booting DOS.
- scroll thru the native autoexec.bat at C:\
- look at the contents of C:\ (dir command)
- starting CNC7M4 & bed homing routine commence
- bed homing routine continues....
- bed homeing routine continues ....
- bed homing routine completes successfully & we demonstrate command control
- demonstrate tool rotate & starting a head skim program

I believe that this is Centroid software "system 5". we have in 2019 upgraded this thru Centroid to System 7, but owing to HDD failure within the control PC, we have now lost this. I *understand* (?) that it's licensed to the system serialnr so hopefully Centroid can re-issue this should we require. However, we wish to upgrade this machine to a more current control system, and are very keen for advice on how best to do this based on the CNC machinery we are showing in this build-thread.

A sidethread is that we have (also around 2019) purchased a digitising probe which worked to some extent on this system but had some serious bugs. Hopefully modernising the control system will help us to iron out these also.

Please excuse the poor cosmetic state of this machine, the owner has had some considerable personal upheaval of late but we are now getting back on the rails, and this exercise is a big part of that.

This machine is nominally a "three phase" system. There is much scratching of heads about whether we need a "clean" three phase supply from the electrical utility company to the premises where we now intend to move the machine. I am fairly certain that we can supply this machine from a convenient inverter VFD unit of the appropriate capacity. I would welcome experienced advice on this, because clearly upgrading the site supply from single to three phase represents quite a significant amount of work and expense, whereas installing a convenient inverter drive would be trivial.

[MM0TJR]

Moderator/s - please could you add the Centroid control system serial nr (which is 13461B) and the mill identification (which is Tryax YCM50 sn602763) to the title of this thread. Thanks.

[cncsnw]

The serial number is probably "1346B-1".

That would be a 1000-series control (1993-1998 M40/M50/M60 style); "B" for "board level" meaning that the OEM (Tryax) did the final assembly; and hyphenated because for a brief period ca. 1995-1996, Centroid built multiple kits under one serial number (therefore "1346B-1", "1346B-2", "1346B-3" etc.).

[cncsnw]

I have been told that you need three phase going into the servo power rectifier, if you are going to run the system on 50Hz. On 60Hz service, a single-phase rectifier works just fine, but I understand that is not an option in the UK.

Since there is probably a three-phase transformer between the incoming service and the rectifier, you have some isolation and filtering. Therefore it would probably work okay using a static phase converter, or a rotary phase converter, to provide your 3-phase service.

[MM0TJR]

Please can someone advise on best upgrade path to bring the controller into the current modern world?

[cncsnw]

If the servo motors and encoders are in good working order, then you could upgrade the control with an Allin1DC unit.

The Allin1DC would take the place of the servo drive, RTK2 PLC stack, and CPU7 board.

If you require a rotary fourth axis (as was supported by the old control), then you will also need a DC1 drive to go with the Allin1DC unit.

You would need a PC and operator station, which could be done in any of a dozen different ways:
- Centroid M400 console
- Mini PC, monitor, keyboard, and jog panel pendant
- Mini PC, monitor, keyboard, and no jog panel pendant (just using the on-screen "virtual control panel"), plus an emergency stop button
- Either of the "mini PC, monitor" solutions using an all-in-one PC instead

To use the Allin1DC, you will need a suitable DC bus rectifier. That can be the original one, but you will need to find a source of 3-phase power for it.

[cncsnw]

If the old servo motors or encoders are suspect, or if you cannot supply 3-phase power for the bus rectifier, then you might look instead at retrofitting with new servo drives and motors, and using either a Hickory, Oak, or Acorn control unit instead.

With luck, others in the UK or Europe can help you identify good AC brushless servo motors and drives that will run on 50Hz single-phase power. Something around 750W should be suitable for that machine.