It depends on the control voltage required to drive the valve. If it is a 24V to fully turn ON the valve, you may be able to use the PWM (pulse width modulated) output on the T100MD888+ (2 channels) to directly drive the valve. The average voltage applied to the valve is proportional to the duty cycle you define using the SETPWM output.
However, if the valve require a 0-5V input (reference only, high impedance input), you can use the PLC's analog output to drive the valve. So please check how the valves are currently being controlled to determine which method is best used for controlling it from a T100MD+ PLC.
