It depends on whether what you need is just a smoke and fire detector (ON/OFF) or an analog sensor that can give you amount of smoke it receives.
If it is just a detector that gives you ON/OFF signal then preferably look for one that output a voltage-free dry contact which can be interfaced to any of our PLC digital input.
If it is an analog sensor then look for one that can output 0-5V, 0-10V or 4-20mA. All of them can be interfaced with the PLC's analog inputs either directly or coupled using a one or two resistors to convert the sensor's voltage output to 0-5V that are compatible with most of our Super PLCs (F1616-BA is currently the only one that interface directly to 0-10V sensors).