The CS1W-PDC11: 4 analog inputs, backplane mount, screw terminal. NK marine approval means this module is specified for vessel or offshore installations where classification society certification is required. The CS1W-PDC01 carries identical channel count, mounting, and termination but its approval listing does not include NK — a common substitution point if the end-user does not need marine cert.
CS1W-PDC01 vs CS1W-PDC11
The only documented difference between the CS1W-PDC11 and the CS1W-PDC01 is the presence of NK classification approval on the PDC11. Both are 4-channel analog input modules for the CS series backplane, same 0°C–55°C operating range, same screw terminals. If NK is not required, the PDC01 is a functional drop-in. If NK is mandatory — typical for maritime or offshore control panels — the PDC11 is the specified part.