step-dir to dro

Simple Step/Dir to A+ A-, B+ B- DRO input interface for one axis.

Outputs from my CNC controller are  0-12V signals so there are voltage dividers at Step/Dir inputs. R3, R4 resistors can be omited if the controller outputs 5V signals.

DRO is supposed to be Sino or SNS-3V equivalent. That is to say with A+/A- B+/B- quadrature incremental inputs, TTL levels.

There are 2 footprints and pads for output : Sub-D9 and JST-5pins. One can mount either of them. With male Sub-D9 the module can be connected directly to the DRO input connector. With JST connector, the module can be mounted inside the DRO housing and reuse the internal cable and plug for that axis.

This PCB board has been produced by JLCPCB and it works OK.