I have an eCut motion controller, v1.1.  It is connected via ouput pin 7 and the 0-10V to an Automation Direct GS2 VFD.  I have spindle control working (speed and on/off) from Mach3, however I am stumped on how to get a realtime RPM reading from the board. 

The SP+,5V, SP- and gnd are being used with an NPN sensor (wired per manual), with a magnet on the spindle head.  The eCut features a diagnostic LED for the speed sensor and it does flash as expected in sync with the hall effect npn that is triggered from the spindle.  I have tried a number of configurations, but can't seem to identify one that works as expected.  Any tips from folks that have a working confirmation with this board on how to get an RPM reading?