The 7I76U is daughtercard/breakout board for use with MESA's 25 pin I/O FPGA cards like the 5I25T,6I25 and 7I92T.  The 7I76U is designed for interfacing up to 5 Axis of step & dir step motor or servo motor drives and also provides a spindle encoder interface, isolated analog spindle speed control and 48 isolated I/O points for general purpose field I/O use.  All step and direction outputs are buffered 5V signals that can drive 24 mA.  All outputs support differential mode to reduce susceptibility to noise.  An isolated analog spindle voltage with direction and enable or forward and reverse outputs is provided for spindle control as is a single spindle encoder channel with TTL or differential inputs.  48 points of isolated field I/O are provided for general control use including limit switch and control panel inputs, coolant enable and tool changer control outputs.  Isolated I/O includes 32 sinking inputs and 16 sourcing, sinking, or push-pull  outputs.  Inputs can sense 5V to 28V signals and the outputs can switch 5V through 28V signals.  Maximum output load is 500 mA. Outputs are short circuit protected. In addition to the being able to read digital on/off status of each input, four input pin voltages are readable with 8 bit resolution, and two MPG encoder inputs are provided as an option on four field inputs.  Field I/O is powered by an isolated 5-28V field power source.  One RS-422 interface is provided for I/O expansion via a serial I/O daughtercard.  All field wiring is terminated in pluggable 3.5 mm screw terminal blocks.

The 7I76U is a replacement for both the 7I76 and 7I76D and has these additional features:

1. Field outputs can be set to sourcing, sinking, or push pull modes on a per output basis.

2. Field outputs do not require flyback diodes regardless of load current.

3. The digital spindle interface outputs can operate in ENABLE/DIR or FWD/REV modes.

4. The serial expansion interface can operate in both RS-422 and RS-485 modes.