Constant Current Source Design using myRIO

[Calorified]

I am trying to drive a proportional solenoid valve: PVQ-33-5G-23-01N ( which responds to currents between 100mAand 165mA. I am using a circuit similar to the one in the attachment below except that I am using the myRIO's DAC in place of the AD5446, the LM324(http://www.ti.com/lit/ds/symlink/lm124-n.pdf) in place of the OP1177 and the MOSFET(http://www.mouser.com/Search/ProductDetail.aspx?R=VN3205N3-Gvirtualkey68900000virtualkey689-VN3205N3-G)[/url]

So the challenge I am having is how to configure the circuit in labview. I am trying to use the default FPGA person ality of myRIO. I am supposed to generate a 1.2V Vref signal into the pin 3 of the LM324. By varying the word that is sent to the LM324, I am supposed to effectively vary the current on the Drain terminal of the mosfet. I have wired the Vref terminal to Connector C/AO0 on the myRIO and I have the VI below but I have no experience sending bits and bytes. I would love to drive the solenoid with about 10 -15 steps of current. Any help would be appreciated.

Edited January 8, 2015 by Calorified

[Calorified]

I have fixed this. Here is my updated circuit design and the DAC control diagram

Edited January 17, 2015 by Calorified