Yes they can, but there can be difficulties with enabling the software to operate correctly. The most reliable method is to first install SQL/SMS. Next, install ION Enterprise and MSDE (the two database engines will co-exist on the same system). There are complications with the sa password if the two Suites are running on a unified SQL database.
Also, SMS 4.0 SU2 requires .Net 2.0 framework, while ION:Enterprise 5.5 requires .Net 1.1 framework. These can co-exist on the same system, but may require some configuration for their individual needs.
It is NOT recommended to run ION Eneterprise and SMS on the same system, but there have been some successfull installations.
ION:Enterprise Commissioning Guide:
Last Revised: June 22 2007
All content © 1992-2007 Schneider Electric
Legacy KB System (APS) Data: RESL186703 V1.0, Originally authored by KBAdPM on 07/06/2007, Last Edited by KBAdPM on 07/06/2007
Related ranges: ION Enterprise V5.5, System Manager 4.0