I used to retrofit Heidenhain controls for a living at the time the TNC150 came out & came up with a partial solution to drip-feeding long programs for a customer who machined gas turbine compressor blades. The machines were Bridgeports that were originally controlled with the BOSS (?) stepper motor system. The machines had the knee controlled as the Z axis & had 4 heads mounted on a hammerhead shaped overarm - 4 blades were machined simultaneously. We replaced the steppers with dc servomotors & encoders (the same SEM motors & ERO encoders that Bridgeport used) & fitted the TNC150 - then just out. I guess that this would have been around 1984 - doesn't seem like 30 years ago !
I got around the 1000 line program limit by using a feature of the built-in PLC ( the PLC was one of the new features of the TNC 150 over the TNC 145 it replaced) - keystroke emulation - and the customer's download device. Basically the program was split into segments of just less than 1000 lines at a change-over point in the machining of the blade profile. Each program segment was called "Program 1" & numbered from line 1 - the segments being arranged for download sequentially on the download device, which deleted each segment after it had been downloaded.
An M code was programmed at the end of each segment that was decoded by the PLC program, which initiated a series of key strokes that :
Pressed Cycle stop, then internal stop to abort the program run
Changed to Program & Edit mode
Deleted the Program 1 in memory
Selected download Program 1 from the external device and pressed Enter
Generated a dwell longer than the time taken to download 1000 blocks
Selected Program Run Full sequence
Selected Program 1 to run from memory
Pressed Cycle Start to run the program
This arrangement worked very well, with just a short delay while each fresh segment loaded. The screens changed in the same way as if you were stood in front of the control pressing the buttons. We retrofitted 8 machines for this customer, which ran on a 24 hours / 7 days a week basis.
As I no longer work for this company I don't have access to the PLC program back-ups any more, so can't supply you a copy I'm afraid.
The TNC 150 Commissioning manual gives details of how to program the PLC & the lists of signals between the control & the PLC. The standard Bridgeport PLC program is kept on an EPROM, but it is possible in parameters to set the PLC to run from RAM & the EPROM program can be copied into RAM to be modified via the keyboard. Access to the PLC is via Code Number 941026. Heidenhain have made the manuals for the obsolete controls available on their website - look under OMA (Operating Manual Archive) in the downloads section.
I don't recall using this for any other customers, though as the TNC 151/155 came along a year or so later with drip-feed capability there was no longer a requirement for it. If you go looking for a TNC151 to replace your 150, be aware that there were 3 different interface versions - make sure that the one you get has the same "2 rows of 3 x 10 pin" interface connectors under the metal cover at the rear + 5 x round encoder/handwheel connectors. There was a version that used a remote (extended capability) Input/output board that didn't have the 10 pin interface connectors (just a 37 way D-connector) and another version that used 5V TTL encoder feedback rather than the "usual" 11 micro-amp sinewave feedback - this has a multi-pin Harting connector instead of 3 of the circular encoder sockets. A TNC155 should also work - though I can't remember if the larger monitor was compulsory for the 155 to show the graphic simulation.
Regards,
Nigel B.
