Fx2424 is NOT a drop-in replacement for T100MD2424. In most cases you can get by with small modifications if you want to use Fx2424 to replace T100MD2424+. Note the following differences:
1) Output 7 and 8 on T100MD2424 are PNP type (ON = 24VDC, OFF = 0V DC). All outputs on Fx2424 are NPN types (ON = 0V, OFF = open circuit (with weak pull up to 24VDC)
2) On T100MD2424+ the Analog output 1 and 2 shared the pins with analog input 7 & 8. On Fx2424 the analog outputs are on their own dedicated pins.
3) On T100MD2424+ the PWM channel 1 and 2 are on output 7 and 8. On Fx2424 the PWM channel 1 to 4 are occupying output 5 to 8
4) On T100MD2424+ the high speed counters shared with input #3,4,5,6. On Fx2424 the high speed counters shared with input #1 to #6 (there is an additional high speed counter on Fx2424).
These difference may or may not be applicable to your applications, depending on whether you are using these features or output 7 & 8.
The exact same program that ran on the T100MD2424+ however can be compiled and transfer to the Fx2424. You just need to ensure that the special I/Os are wired to the correct terminals.