Hi Frankee,
I'm not sure I understand what you mean. An input signal?
KFLOP has Virtual IO bits (IO numbers 48-63) that you can Set/Clear from a C Program. Or you might use one of the KFLOP LEDs (#46 or #47). You can configure inputs in Mach3 in the:
Mach3 | Ports&Pins | Inputs
Set the Port as 1 and the Pin as the KFLOP IO Number.
You can then poll that Mach3 input in the Mach3 CB Script.
To pass floating point values between Mach3 and KFLOP see:
Mach3 Plugin Passing DROs
HTH