Im looking into both OBD and FMS. I have read that FMS provides more data, yet obd seems to have much more PIDs available? Is this correct or am i missing something. Thank you
FMS and OBD are different things.
FMS (Fleet Management System) is used in telematics, you can track vehicle speed, fuel, coolant temperature, GPS location, brake, clutch, gas pedal and more with it.
OBD (On-board diagnostics) as you can guess from the name is more for diagnostics of the vehicle. OBD systems give the vehicle owner or repair technician access to the status of the various vehicle subsystems.
It really depends what you want to achieve, if your goal is telematics FMS is your thing, if it's diagnostics OBD.