trasconductance amplifier for pneumatic valve control

The project is based on a linear costant current, to generate two level of current , the first is to engage the Pneumatic valve normaly duration is 1mS the second value is for the sustein. The first pulse is 1Amps the second is 200mA the two level is trimming on board at desired / required value , the power input of board is 24V, the command ( PWM ) is wide range fromTTL value to 0-24V ( discrete value) . On input are present clamping voltage and pull down resistor to assure NO command current to valve when input is floatting in this way the command accepted from PLC is the type open to 24V . The output have additional current limit to protect from short of the valve . The current trip from level 1 ( 1Amps ) to leve2 (0,2Amps example ) only the PWM CMD is grather than 1mS