I recently purchased a TC Helicon voiceworks effects rack. I have it Hooked up via a s/pdif connection. Two s/pdif cables, in/out  out/in. How do I get X2 to recognize the unit so I can use it as an external effect. I do have the ability to track through it. But I haven't figured out how to add the effect to a dry track. Any ideas?

What do you have the TC hooked up to interface wise?  It should be as simple as SONAR sending out a signal to the interface and the interface passing the signal on (and returning it) via s/pdif.

@

A Tascam us-1800. 

X2 will not recognize the unit - it will "see" the input/output digital of the tascam that you have hooked up to the tascam.  X2 has no way to know is hooked up, except for midi.  So be sure and hook up the midi.

Then it is only a matter of sending the track you want to effect to the tascam digital out and then routing the digital return to SONAR's master (or a new track if you just want to record IT).

Signal flow can get confusing when you are dealing w/ a DAW, interface and external equipment.  It wasn't designed for it, unlike an analog board.
@

Actually I found the midi control of this unit rather a pain so abandoned that approach. It was cool to switch the presets from within Sonar but having it in a midi chain did not always yield the intended results. Just make sure you have the clocks synched between the tc and the tascam and they match with your Sonar settings. Then use the external insert feature on the intended track (or better still use a buss you can route your track to which points to the tc ports) and set the  correct spdif ports for in and out in the external insert interface. I use it this way all the time.

Sync the clocks......I guess you know what the next question would be. Thanks Middleman

You can use external hardware "insert plugin" in SONAR X2.
All latency compensated too. Patch and send "out!" to SPDIF OUT to input of SPDIF IN.

It might do it automaticly. If your getting sound then all is good, otherwise you'll get a wordclock warning either from Sonar or the TC. 
Best if  Tascam ( Sonar)  is the Master. It will also depend on if the TC supports the same clock rate you've been using to record in Sonar. I have to use 44.1 as my Yamaha 01v does not support 48 or higher. 
I have a us1641 which is the same and I have used external devices and the SPDIF all the time. 

Here's one way to do it, there are others. 
Insert a new audio track and point it's input to the SPDIF which will show at the very bottom of the input list. Use stereo.   

Now set up a bus that is pointed at the SPDIF output. 
Buy adding this buss send to any track you'll be able to route the signal through the effect. The effect will be printed to the track you made. From there you can do a few things for mixdown. I assume your after harmonies. 

Don't forget, you can only use the SPDIF output OR  output 3/4. Cannot use both at once. 

keneds


Sync the clocks......I guess you know what the next question would be. Thanks Middleman

It can only be one clock, one MASTER clock in the studio. I recommend that you set it up so your Audio card is the MASTER or if you use TASCAM DM 4800 act as MASTER clock! All other units sync to that clock. The Sync clock are then send thru the ADAT + SPDIF signals so don't worry about the TC. It will lock to that sync signal as well. Example audio frequency 48kHz embedded sync/ 30 fps audio.