Hi zeroprog, welcome to the forum,
zeroprog wrote in part:
I do not wish to power the arduino and valve off the 24vac line. This is more of a control project so on/off won't do (well i guess it would but i chose 2-10). My question is, how would I go about wiring the arduino output to the actuator control input? I understand somewhat how to get the analog 2-10 or use pwm but will simply tying the arduino output into the actuator input work?
Firstly, the actuator, if it is designed to be powered from 24VAC, then you don't have much option. It will need this power supply to work.
Unless you can get inside and work out if it can be adapted to work off 24vdc if that is of any help.
For the input signal of 2-10 volts, which is an industrial standard (albeit old), you will need some electronics between your Arduino and the valve.
Check to see that the valve can be configured to operate from other standard signals, such as 1 - 5 vdc or even 4 - 20mA as this might make your interfacing easier.
But if you are stuck with using 2 - 10 vdc then you may simply use a op-amp circuit with the correct amount of gain, X2 if you have 0 - 5 vdc from the Arduino. You will need the right amount of filtering on the op-amp input to smooth out the PWM if use use that.
Alternatively, you could build a simply R2R resistive ladder network driven from Arduino digital output pins that will give you a crude DAC which you then feed into the op-amp buffer driver circuit.
First, check your options for valve supply power.