I'm with Clive on this one (standing on the shoulders of the LInuxCNC giant :). - check that gmocappy needs or doesn't need a spindle-at-speed signal, then use the monitor to check the state of the signals that lead into this.

Apologies - I've not looked into this myself but from distant memory the Axis GUi for LinuxCNC (the name of which confused the hell out of me at first) has similar.