DNC with parallel port (Bridgeport BOSS 5)?

[hobbymat]

Hello CNC-knowledgeable folks,

I'm looking for an inexpensive solution to transfer long programs to my "new" toy, a very old Bridgeport CNC mill with BOSS 5 control. It was broken when I bought it, but some new transistors for the stepper drives made the mill work again.

The problem is that the control only has 8 KB of memory, so the best solution would be to drip feed the long programs into it somehow. Unfortunately the RS-232 port in this machine does not use any handshaking, but I understand that this could be overcome using the (parallel) tape reader interface, like with a separate BTR card. Obviously some DNC software packages can be configured to use the PC parallel port for this BTR emulation mode.

Has anyone written any simple program that just acts like a tape reader and feeds the control one line at a time when needed?

I'll be retrofitting this machine with a modern PC control (Mach2) quite soon, hopefully using even the original stepper drives, but I would like to use the original control for some time first and make some chips and parts before I dig into the electronic internals of the B'port. That's why I would like to stick with very simple and inexpensive solutions for DNC. No bells and whistles are needed, just the drip feeding function.

Of course an adapter/optoisolator card would probably be needed to connect the parallel port to the tape reader, but it won't be difficult to build. The problem is that I'm not a software guy, so writing the as-simple-as-possible program for this use is not easy for me...

I'd be grateful for any info on using the BOSS 5 control with drip feed from a PC.

Thanks,
Hobbie

[machintek]

The memory in a BOSS 5 is very small. It was not desined for 3D programs and such. BUT! A long time ago they did make a DNC loader. In 20 years of BPT service, I have seen only one shop using them. They were making turbine blades. You will probably wind up retrofitting the machine with something like a AH-HA control that is PC based and can store and run long programs. It uses the existing stepping motors to keep costs down. Remember that this machine steps with .001 inch resolution.

George W.

[Pat Kriel]

If you find a answer please let me know. Pat

[andre-dolphin]

Communicating with a BOSS controller is difficult to say the least.

The software is not a simple "drip feed" solution as it must emulate a teletype terminal that was original equipment with the controllers.

I have connected to lots of BOSS controllers over the years as we have written a special emulator into our PartMaster DNC software. BUT .......

Be aware that there are two AMP connectors on the BOSS controller in Europe, (don't know about USA) 1 is RS232 the other is 20ma currrent loop. Connecting to the wrong one and sending data into it can have nasty consequences.

There is a comms board in the controller located behind the grill/dirt filter on the right hand side of the machine. It will be lablelled "K", on this board remove the connector K10 to enable RS232 interface.

You wont be able to drip feed into the controller even if you get the RS232 working, for this you would need a BTR card with it's own memory.

If you're going to upgrade to MACH then that is the best option.

ATB
Andre