When I asked about this before, I had hoped someone would have seen one of these before. Since that didn't happen, I opened it up and took some pictures.
This is a Bridgeport mill with a 2-axis CNC controller and a 3-axis DRO, owned by a member of Milwaukeemakerspace.org The front panel looks like this: http://www.panix.com/~rbean/temp/bridgeport/front-panel.JPG All program entry is through this control panel. There's no obvious way to connect it to a computer. Label on the back panel: http://www.panix.com/~rbean/temp/bridgeport/back-panel.JPG The connectors labeled X, Y, and Z are for the DRO. [Note the connector for the cassette-tape interface, which we don't have] Label on the power supply: http://www.panix.com/~rbean/temp/bridgeport/power-supply.JPG Note the date: 9/89 (~25 years old) The servos and encoders plug into this box, and there's a cable from here to the control box. In addition to the power supply, this box contains two boards labeled "X" and "Y", I assume these are servo amps: http://www.panix.com/~rbean/temp/bridgeport/servo-board1.JPG The big thing in the middle is a heat sink, with power transistors on both sides of it. The data connection is on the other side, through a hole in the plate it's mounted to. Visible chips include: TSC426CPA dual power mosfet driver TSC427CPA dual power mosfet driver HP 2601 line receiver optocoupler HP 2531 optocoupler Another view of the board: http://www.panix.com/~rbean/temp/bridgeport/servo-board2.JPG Here are two views of the servo encoders: http://www.panix.com/~rbean/temp/bridgeport/encoder1.JPG The chip is a DS8830N dual differential line driver http://www.panix.com/~rbean/temp/bridgeport/encoder2.JPG The chip is a HEDS9000 optical incremental encoder Here's the label on one of the servos: http://www.panix.com/~rbean/temp/bridgeport/label1.JPG http://www.panix.com/~rbean/temp/bridgeport/label2.JPG Unfortunately it's very hard to read, and it appears that the vital info was not filled in. Here's what I think it says: DC MOTOR 60 V A RPM DUTY CUST P/N 14969 REV D I G P/N 4020D-143 S N 4320 ASSEMBLED IN MEXICO BY INDIANA GENERAL HPL 730-352 Finally, here are the two logic boards inside the control box: http://www.panix.com/~rbean/temp/bridgeport/logic-board1.JPG http://www.panix.com/~rbean/temp/bridgeport/logic-board2.JPG (I just realised these pics are upside down :-) Each board has a MC6809 CPU and a whole bunch of 74LS-series logic chips. I think the chips in the yellow packages are resistor networks. Also visible on the 2nd board are: Intersil ICL232CPE dual line driver/receiver MC6850P UART MC1411P (7 darlington drivers) And some other stuff I couldn't identify. The owner says the machine is usable, but one axis stops working occasionally (I don't know which one). He'd like to get it working reliably with a way to input programs from a computer, and add a Z axis servo. Questions: Are these servos likely to be usable? Are the servo amps likely to be usable, and if so, what kind of input might they be expecting? [Do servo amps want step and direction inputs, or something else?] Do servo systems like this use a combination of data from the DRO and the servo encoders, or is the DRO separate? If you wanted to modernize this machine and add a 3rd axis, how would you go about it? We've gotten some interesting but questionable suggestions from members who were born around the time this machine was made... Some people assume it must use Gcode internally, and there must be a way to load Gcode into it from a computer. I think both are unlikely, although I suppose it's possible. The connector between the power box and the control box "looks like" a serial port, but I doubt it. The idea of somehow loading data through the cassette tape interface seems unlikely to be worthwhile, despite one member's insistance that it would be a reasonable thing to do. In any case, that wouldn't get us a 3rd axis, nor would it explain why one axis occasionally stops working. Several people have suggested replacing the servos with big steppers, on the theory that stepper drivers will be cheaper than servo drivers. I don't know if that's a reasonable thing to do or not. One member works for a company that's about to throw away a somewhat newer conversion kit (perhaps only 15 years old instead of 25), and he's asked them to consider donating it to us instead. That's working it's way through their bureaucracy, I'll believe it when I see it. Any other suggestions or comments? ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. This 200-page book is written by three acclaimed leaders in the field. The early access version is available now. Download your free book today! http://p.sf.net/sfu/neotech_d2d_may _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
