Messages

121

General Mach Discussion / Re: Integrating Namur sensors - Denford Triac

« on: May 04, 2009, 02:48:54 PM »

Thanks for your reply NosmoKing. I have tried to respond to your points as best as I can.
1) I can take the 12v from one tapping of the transformer that is powering the stepper motors and other original equipment. This feed is, therefore, unchanged from the original machine.
2) I thought I might need these to 'pull up' the inputs to the PC as it was my intention to link the PC inputs to pins 2, 17, 4 & 15 on the circuit board where once was IC8. That is, as IC8 has been removed I can easily solder in sode wires.
3) There are no jumpers available for IC's 4 to 7. I have attached a info sheet for these MCT6 devices but they are pretty simple things.
4) I thought I would keep the 12v away from the PC as both 12V and 0V can be accomodated on the original board.
5) I have also attached a photo of the board which should give you a better idea. You will be able to see where IC8 has been removed from, which is where I intend soldering in my new connections. You can also see where resistors RP2 has been removed.

What I am really looking for is an idiots guide to wiring this thing into the parallel port; i.e. "pin 2 of where IC8 was removed from goes to, say, pin 13 on the parallel port" etc

thanks ...Sweep

122

General Mach Discussion / Integrating Namur sensors - Denford Triac

« on: May 02, 2009, 12:23:06 PM »

My Denford Triac 3 axis milling machine is fitted with Namur type sensors for XYZ Datums/Homes and mechanical switches for overtravels.
The Namur sensors are 2-wire devices and, after doing a bit of research, I understand that they signal their condition by allowing a different amount of current to flow over them. This current is very small being, on this device, only 0.3mA. This small amount of current flow allows them to be used in ATEX (Hazardous) environments etc.
Before I stripped the machine for Mach 3 conversion all three detectors worked everytime and I never had an overtravel event. This, and the problem of replacement cost for 3-wire devices, as focused my attention on keeping them for the conversion.
Unfortunatley, these Namur devices normally need an amplifier which takes the current difference and does the actual switching and these things are more expensive than the 3-wire devices I am trying to avoid buying.
So, with a bit of careful hacksaw work I have cut the Datum section out of the huge original Denford motherboard (15"x16") and am left with what, hopefully, is the bit I need in working order (yet to be tested!).
Take a look at the attached wiring drawing and the bit I am left with is in the bottom left hand corner. I have then removed IC8 to allow me to use pins 2, 17, 4, & 15 for the Dtaums and spindle speed monitoring. As you will see the supply voltage to that side of the circuit is 5V which is lucky, whilst the 12V on the sensor side can be supplied from the origiinal Denford transformer.
Now I think have already taken one step too far as I have also removed the resistor decade RP2 but that can be replace with the same or differnt value.
So, I know it might not be conventional practice to hacksaw up a circuit board, but I would appreciate some advise on my 'project' and, more importantly, how do i now wire it to the PC? To be honest I never really undertood when regarding 'inputs' to the parallel port, whether the PC supplys the 5V or it has to come from elsewhere. I would appreciate guidance on this as well as I don't have a 5V supply from my existing transormer, only 7V.

thanks in advance ...Sweep

123

General Mach Discussion / Re: wiring diagram for limit switches

« on: October 28, 2008, 02:53:33 PM »

I thought I would tag my question onto the bottom of this old post as it seemed pretty appropriate.
On page 4-8 of the Mach3 users guide there is a diagram for wiring the limit switches. What I don't understand though is what the 5volt supply does. I have tried taking a +5 volt from a USB and feeding it via a 470ohm resistor but it doesn't work. I then read the mail below and that suggests that the PC has its own +5v supply from the parallel pin port (PPP) and that the PPP has its own built in resistor, though that seems to contradict what is written by Art & John Prentice on page 4-9; "Note that for relaible operation you need to "pull up" the input to the parallel port. As mechanical switches can carry a significant current a value of 470R is shown which gives a current of about 10 milliamps."
I have run a simple loop from a PPP input via my machines proximity switches back to PPP 0volt and that seems to work fine so I guess that what is written on this earlier thread is true, but I can't ignore what is written in the manual.

Clarification would be appreciated

Thanks ...Sweep

124

General Mach Discussion / Re: Starkstrom MPG connection

« on: June 08, 2008, 06:33:12 PM »

Thanks Hood.
I have a digital oscilloscope so I will give it a spin hooked up to that first.

...Sweep

125

General Mach Discussion / Re: Starkstrom MPG connection

« on: June 08, 2008, 04:28:24 PM »

So a 5v supply from, say a USB, to power the MPG and then wire the S90 and S0 to two inputs from the parallel port, plus the 0v ?
I guess this info must be in the main manual but I just can't see it

thanks ...Richard

126

General Mach Discussion / Starkstrom MPG connection

« on: June 08, 2008, 12:43:18 PM »

I have been given a Starkstrom MPG and wondered if anyone could advise me how to hook it up via the parallel port. I have searched both this forum and the yahoo groups, and looked through the main manual but can't see anything for actually connecting the wires.
The back of the MPG has four screw terminals : S90, +UB, 0V, S0, and I am assuere it is a 5 volt device. I have attached a photo which, usefully, shows an internal wiring diagram ...I think !

Thanks ...Sweep

127

General Mach Discussion / Re: PWM as a digital information carrier (?)

« on: March 10, 2008, 04:19:11 AM »

Thanks for your support Vmax.
I am pretty sure that you are correct about the rs232 as the machine has a built in cassette player that uses rs232 for programming, and if this is correct then there must be a simple PC program for encoding this onto the cassettes in the first place.
I have a copy of the machine manual and more toolchanger circuit drawings that I have emailed directly to you. I haven't attached them to this post due to the number of pages. If anyone else would like to contribute to helping me please let me know and I will send you the files directly.

Thanks ...Sweep

128

General Mach Discussion / Re: PWM as a digital information carrier (?)

« on: March 09, 2008, 06:05:18 PM »

Thanks Vmax, but I am already a member of the Denford forum but they cannot help me.

I have had a look through the old manuals I have for the machine (downloaded from the Denford forum) and I think you are both right to suggest rs232. Have a look at the attached diagrams and you can see why it is not the easiest question for anyone to answer; they all seem to be rough hand-drawings! To make matters worse my machines ATC has serial number 001 so things would have probably have changed almost immediately.
A couple of things in my favour though, if you are correct about Mach only being able to send rs232 info, is that on picture 30.jpg I only have the green and red wires connected. These two wires give the square wave signal I was trying to descibe, with each tool having a different set of 'on' and 'off' periods.
I started to check the remaining three wires, shown on 'triac-toolchanger-link.jpg' when I had to stop for the family's evening meal but I should get them scoped tomorrow.
If these just give a constant 'run' or 'fault' signal then I guess we are in with a chance.

Thanks ...Sweep

129

General Mach Discussion / Re: PWM as a digital information carrier (?)

« on: March 09, 2008, 03:19:21 PM »

It could be, but what's that 
How do I recognise if it is RS232 and does it make it easier to solve my problem? Can Mach3 speak this RS232 language.
If you can point me in the right direction to find out this info I would appreciate it as I am a Mechanical, not Electrical, Engineer. I have just bought myself my first oscilloscope (DSO) to try and sort the problem.

Thanks ...Sweep

130

General Mach Discussion / PWM as a digital information carrier (?)

« on: March 09, 2008, 11:35:58 AM »

I am not even sure if I understand the title of this mail, so i'll try explain what I am trying to achieve. 

I have modified my Denford Triac ATC (bulit 1990) to have XYZ and spindle speed controlled by Mach 3 and it works great.
The Denford's main electronics are mounted in a slide out tray underneath the drip-tray, whilst the ATC electronics are mounted in a seperate panel. The two are connected together by two signal leads with a total of 3 wires (plus grounds). Two wires seem to carry the 'initiate tool change' and Fault signals, whilst one wire carries the information for which tool number is needed on the change.
What I am trying to achieve is to replicate this signal directly from Mach3 if possible, or, say, ModIO if that is easier.
I know Mach3 can generate a PWM signal as I am using that for spindle speed control, but can I programme this as part of a macro and change the 'on' and 'off' period' between each individual pulse to replicate the square wave signal currently being sent from the Denford? The smallest 'on' or 'off' period' I have measured on my scope is approx 0.1ms and the longest approx 0.5ms, with the full data stream taking around 150ms. The 'on' voltage is approx 11.5v.
I would really like to do it this way as the existing carousel toolchanger has pneumatic logic which looks after all the tool positioning and installing procedures, except carousel rotate, and all this is controlled by the existing system. To change all this would be a nightmare.

Any help would be greatly appreciated.

Thanks ...Sweep