25mm vs 35mm IO Modules

Hello Mates,

I'm looking for the S7 1500 as a replacement with better cost for the the S7 300.

Basically what would be the main difference between the 25mm wide modules for the 35mm wide modules?

Like a 32DI 35mm 6ES7521-1BH50-0AA0 vs 32DI 25mm 6ES7521-1BL10-0AA0?

Does 25mm modules have removable connector? 

For a 35mm kit, I need to buy: CPU + MMC + RAIL + 35mm module + Front connector

For a 25mm kit, the same thing minus the front connector, right?

Does the expansion connector between modules is always included?

Greetins,

Renan

Do you mean the difference between ET200S and ET200SP? with both you need a terminal. With ET200SP you need to specify terminal with a potential group or not (white vs. dark) because you don't use the PM (power modules) with ET200SP (25mm). The 25 mm modules from my experience have push-in terminal connections as opposed to screw terminal option for the 35 mm module. With 35mm modules you have a third party connector option (Phoenix)

I hope that helps.