Siemens Simatic S7 Series Manual page 28

Expansion Modules.
Mounting.
S7-200.PLCs.are.expandable.by.adding.expansion.modules..
Expansion modules.with.inputs.and/or.outputs.are.connected.
to.the.base.unit.using.a.ribbon.connector..
SF/DIAG
The.ribbon.connector.is.protected.by.a.cover.on.the.base.unit..
Side-by-side.mounting.completely.encloses.and.protects.the.
ribbon.connector.
SF/DIAG
S7-200.PLCs.can.be.mounted.in.one.of.two.ways..A.DIN.clip.
allows.installation.on.a.standard.DIN rail..The.DIN.clip.snaps.
open.to.allow.installation.and.snaps.closed.to.secure.the.
unit.on.the.rail..The.S7-200.can.also.be.panel.mounted.using.
installation.holes.located.behind.the.access.covers.
27
Din Rail