Denford Software & Machines

hi

we have an easiturn 3 lathe, behaving badly.

initially the machine reported error "m/c exceeded limits", ok so i strip the cross slide down to inspect the proximity sensor, only getting 2volts at this item, also the micro switch was mashed. attempts to find replacement sensor failed to produce results. school holidays came.....upon return looked at m/c again....now getting 8.53 volts at proximity sensor but the datuming of m/c runs to x minus and not x plus when pressing zero at start up, resulting in rear microswitch activating and error message report

pressing t at start up displays

inputs 01111111
printer 10
dil switches 110010
cassette 0111
datums 0001
step and dirn 11000000
drive faults 0011

pressing s at start up displays

7 actual 5b correct 5b
7 actual e6 correct e6
8 actual bf correct bf
8 actual d9 correct d9
9 actual bd correct bd
9 actual 13 correct 13

any help will be appreciated

with thanks

It's probably irrelevant, but one of the DIL switch settings changes the bed (Z) length. I wonder if it, or another switch also alters X?

For sake of opening the cabinet up - it might be worth a play!

Si

thanks for response Si i'll try anything

please help me with what are the dil switches where are they located and what am i looking for to recognise a change, if any

ever optimistic

techy

Right, assuming you have the same controller as me (a North east electronics VMC3).

Looking from the front of the controller box, there is the monitor on the left and the tape drive on the right. At the rear, there is the RS232 port on the right which connects to a board (also on the right as you look from the front).

On that board, close to where the RS232 connects, there is a block of 8 tiny switches A bit like this:


Your manual will tell you which one to fiddle with. If not, I'll have a look when I get home!

Si

thanks for the quick response

our controller is a pnc3 but have checked the manual and foundsection on switches I am not in until friday so will have a look then however there dosn't appear to be anything on datum running to x minus instead of x plus

will let you know what I find
this is now a challenge, man vs machine

techy

Have you tried the "T" test?

if you power up the control (PNC3) & then press the "T" it lets you in to the digagnostics page.You can then activate the datum the datum switch manually & check the inout.

martin

see first post for 't' test results

not sure i fully understand 'activate datum manually' unless you mean operate the micro limit switches
operation manually whilst in t (diagnostics) mode of these switches shows overtravel in the respective direction of manual operation.
the immediate issue is that pressing zero after power up results in the cross slide traveling to x minus and traversing right through to the limit switch resulting in the overtravel error message

thanks for the suggestion

techy

Si

located switches and yes is variable between two sizes, however, changing this did not resolve problem.......will keep looking for solution, on the bright side i have learnt someting new

thanks

techy

While in "T" test mode manually activate the datum sensor by placing a piece of metal over it & check if the datum changes. I am not sure which diagnostic is for which but you should be able to comare it to the X axis proximity sensor.

hi martin

maybe getting somewhere now.....though i,m not sure where........'t' test now giving a datum reading of 1101.......placing metal plate in front of z axis prox sensor changes the reading from 0 to 1 (ie 1111) however same test on x axis remains at 11 so it looks like i have a problem with the x axis sensor, though i don't see why it should cause datum to run to x minus

so now i have the problem of where to find a new sensor .....is it a npn or a pnp and where to find a sensor of same legnth 35mm would interfere.

thanks for your help to date

techy

do a search on the site. I know someone was asking which they were and I tested an old one I had. I think the one that was wanted at the time came off a easimill so try searching on that. At worst I might have my old one around....

The axis is probably going the wrong way cos it's backing off the switch until the contact opens.

Perhaps the wire is broken...??

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Hello "techy"

I agree with Triac Whizz, most likely a sensor/switch issue, I have had this problem occasionally with CNC machines over the years and it is usually the sensor/switch at the "Home" ( X plus in your case ) position being faulty or simply stuck in the position it would be if the machine was at that coordinate which makes the control think that the machine is already at the "Home" position so it does it`s normal move away and then the switch should operate again and the machine then moves back again to the "Home" position and stops.

If there is a fault on the switch/sensor/wiring and the control does not get the signal that the switch has operated on the move away from X Plus then it just keeps going and will only stop when it hits the mechanical stop at full X Minus and then you get an "over travel" alarm and the machine trips out!
I suppose it is possible that there is a drive card problem that is producing the same symptoms but to be honest I think that is unlikely.

I always leave all my machines ( 2 Hurco CNC Mills, 1 Sugino CNC Drill Tap and 2 Denford Cyclone CNC Lathes ) in a "Park" position when not in use so that none of the X,Y,Z limit switches are operated and likely to stick.

Regards
Rob



.

Hi Guys

Thanks for info....all starts to become clear .....I have ordered sensor using the easymill part number (thanks triac wizz and bradders) which denford advise has an 80% probability of being correct for the easyturn lathe.

for future ref purposes the micro switches (x limiters) are
rs part number 317-998 and the denford sensor part number is BI00401A with blue & brown lead, a 5/16” Treaded Barrel and a legnth of 1"

hopefully this will resolve the problem and we can make some swarf

will let you know outcome when available

regards

techy

sensor installed m/c working fine.........sensor has 8mm tread not 5/16 as stated in previous post

thanks for all your help guys

techy