Maybe I am not understanding what you are meaning but if I am then the axis should not move when it is E-Stop, reason being is the Enable should be taken away from the drive. It sounds like you have not done that and no amount of messing with the DAC offset will cure that.

Hood

You are correct I connected enable (SON) outside the CSMIO for now (for testing) and assumed the DAC would have 0V when EMG signal is enabled. I'll fix the SON wiring.
If the EMG=off, SON=on, no active NC code, then servo should be actively locked in position by controller and have 0V on analog output. Correct?

If the drive is enabled and Mach is not in Reset then the IP-A will keep the axis in position. There may be a voltage on the analogue signal wires but this will be keeping the axis still.
Hood

You are correct I connected enable (SON) outside the CSMIO for now (for testing) and assumed the DAC would have 0V when EMG signal is enabled. I'll fix the SON wiring.
If the EMG=off, SON=on, no active NC code, then servo should be actively locked in position by controller and have 0V on analog output. Correct?

Coincidentally, I just sent an E-mail on this topic to one of my customers. Here is a snip from that e-mail that should be helpful:

These drives can be used in a large variety of applications and thus have a large amount of capabilities. No one application will use all of them. The [ "L" ] signals you mentioned might be used for a conveyor or similar application. Not applicable to your use, but the drive is 'watching' them so they need to be 'tied off'. You can tie off signals in the wiring and you will see one jumper in the example diagrams I supplied. The drive will NOT come on-line if the EMG (EMERGEMNCY i.e. E-stop) is active. Like the travel signals you have discovered, the EMG (this is E-stop IN to stop the drive) is not needed with MACH, but you still have to kill the signal by grounding it or the drive will be in perpetual E-stop. Look for the jumper in the connector on the wiring diagram. Now you know what it is for. 

In MACH, the drives inform MACH of a problem and MACH then stops all of the drives. i.e. centralized system E-stop. I recommend that you use MACH for this purpose

XYZ axis are all configured and working with the SON signals going through a ULN2802A circuit for now. Have ordered Phoenix opto-isolated SSR DIN mount relay for permanent SON. Still tweaking parameters for optimal speed but working overall.

Spindle is working with analog signaling. Looking at the tool changer set up next. There is a fixed position 16 tool tray (2 rows of 8 ) with pressure switch for tool length measure on the tray and an air operated collet on the spindle. Googled around but didn't see any step-by-step guides so it looks like this will be challenging.
Any suggestions for tool changer macros ?

Appreciate all the help !

Looks like I would be using the CSMIO based tool changer code. They have an example on their site that I will have to dig into.
VisualBasic and Cypress Enable - Oh joy !!!