Scope question-triggering

[Mbira]

I am going crazy trying to figure out how to do this triggering.  I am brand new to triggering in general, but specifically, I am trying to calibrate a VCO.

I have a 30Hz 1Vish ramp wave going into my scope (a tek 454a).  I'm trying to have the wave trigger on the negative slope.

Specifically, I'm wanting to trigger on the negative slope and then position the crest of the ramp in the center line.

The problem is I can't get my dang wave to stop scrolling. 

I'm using these settings:

Signal into channel 1
DC coupled
Mode set to Norm and Channel 1. 
Sweep mode set to Auto Trig
Slope set to negative
Triggering set to
DC coupling,
Source Line

Any help would be greatly appreciated!  I've been twiddling knobs here for an hour trying to make this work!

If you want to see a video of the guy doing what I'm trying to do, here it is:
http://youtu.be/5gs-xL4JdT4

He talks about the scope setup at about 2:00

 

[Mbira]

Not sure if it makes a difference-the lowest point of the slope is about .5V, so it never goes below 0V...


Bah-I just learned about the "level" feature.  I went to delete this thread but I can't....