S5-101U
Compact-PLC for various maschines, can be upgraded with one extension-unit for more in-/output signals.
S5-101U System manual (english).pdf
6ES5101-8RB11SIMATIC S5-101,
PC 101R programmable controller, AC 220/240V, 10 DI, 6 RO
6ES5101-8UA12SIMATIC S5-101,
ZG 101 CENTRAL UNIT, AC 230V, 20 DI, 12 RO
6ES5101-8UA13SIMATIC S5-101,
ZG 101 CENTRAL UNIT, AC 230V, 20 DI, 12 RO- 6ES5101-8UB12
SIMATIC S5-101,
CC 101U CENTRAL CONTROLLER, AC 230V, 10 DI, 6 RO 
6ES5101-8UC11SIMATIC S5-101,
EU 101U EXTENSION UNIT, AC 230V, 20 DI, 12 RO- 6ES5101-8UW13
SIMATIC S5-101,
ZG 101 CENTRAL UNIT, AC 115V, 10 DI, 6 RO