Adopt 62443 to Your Role, Zones, Target Security Levels and Suppliers.
The 62443 family covers asset owners, product suppliers, integrators and service providers under one number, which is why most adoption efforts begin in the wrong document.
Our personas place you in the series: 2-1 for the CSMS, 2-4 for what you require of integrators, 3-2 for zone and conduit design, 3-3 for system requirements, 4-1 and 4-2 for what you demand from suppliers, and where SL-T meets SL-C once the plant is running.
Adoption without buying a certification you do not need.