Yes, I basically agree with Brewery on this.
The SSL can signal ground everything else in the studio (mics, outboard, tape machines etc) that goes via the patchbay as its grounding system caters for this.
Each DL plugged into the SSL should be wired with the screen included. The balanced circuit then goes to/from the patchbay and, as the signal screen is connected there, it becomes part of the console signal grounding. Notice the metal patchbay front panels which are bolted to the console frame. This means that the signal ground of the jacks are directly connected to the patchbay front and hence the frame.
A green wire from each patchbay also goes to one of the copper bars running along the console. The other bar is for the power grounds and they both come together right at the end under the patchbay and terminate in a 0BA (M6) brass bolt.
From there, you should have a big 50/0.25 ground wire going to the computer but, if you don't have this, the console ground terminal should be your main studio signal ground (technical earth), going straight to your fuse box area before going to a ground stake or something else.
This is a complex subject and I have only addressed it in basic terms but hope this is helpful.
Signal grounding and power earthing get further complicated when you have a remote patchbay and unbalanced gear in it sharing the same metal 19" rack strip but I won't go there now as it gets even more complicated (big time)!
