ZMX Stepper Driver 2 Channel Backplane Adaptor


I bought five ZMX Microstepping stepper motor drivers from Phytron during their special intro offer. These boards are designed for 19" rack mounting with a standard DIN 41612 Form D back plane connector. The mating back plane adaptor from Phytron cost as much as the driver, so I figured I'd roll my own.

Downloaded the free version of Eagle, and got stuck in. Since FrankenDeckel is a fair way off, I started with a two channel version, to drive the FrankenSieg the lathe. Later this could be useful, as I'd like to eventually set the mill up for five axis work, but will initially just power X,Y,Z.

I used the Opto-isolation board from NC-STEP so this backplane adaptor is set up for the standard 26pin connector to the Opto, and 10 pin out to the limit switches, spindle encoder etc.

Eagle's freeware only supports 100x80mm boards, so the second motor connector had to be bunched up right up against the DIN connector. I had never used Eagle before, but it is pretty easy to work out. Didn't bother with a schematic, as this is just a few pin to pin runs. In the middle the gound plane runs right up close to the V+ trace, so a cap can be added there if the power leads from the PSU end up too long.

Only the basic step/dir power and motor connections have been done on this board.

Kurt has a great write up on PCB manufacture using the Laser printer toner transfer process. Epson Premium Glossy Photo paper makes lovely traces but is a bear to remove. Epson Photo paper come off really easily if you throw it straight in cold water while still hot from ironing. I really like using this paper. The boards in the pictures are only the second and third I have ever tried, but all three came out perfectly. With 16 thou traces, everything is really clean. Even the dot in etched out perfectly.

You do have to dry the board after removing the toner, as only then can you see if there is some paper fluff still sticking to it, mostly between the tightest traces.

I don't see a difference between prepping the board with scotchbrite and detergeant, or just wiping it with acetone and paper (the board was unmarked though).

***NOTE*** The first version of the board I posted has the Step and Direction traces wrong. I will post a revised version.

V1.1 is the version which is now posted. It corrects the trace error and cleans up the ground plane a fair bit. Here are the PDF or Eagle .BRD files to print on your laser printer.