What is the relationship between the SMARTDAC+ GX/GP series' unit with the digital I/O module (outputs: 6, inputs: 16) (suffix code /CR11), the GX90XD digital input module, and the GX90YD digital output module?

If the suffix code is /CRXY, "X " is the number of GX90XDs installed in the GX/GP main unit, and "Y " is the number of GX90YDs installed. Suffix code /CR11 indicates that one GX90XD digital input module and one GX90YD are pre-installed.