For details on the connection options, see Table 8-22 Connectable conductor cross-sections 
(Page88).
Table 12-8 Pin assignment for X122
 Pin Signal name Signal type Meaning
1 DI 0 I Digital input 0
2 DI 1 I Digital input 1
3 DI 2 I Digital input 2
4 DI 3 I Digital input 3
5 DI 16 I Digital input 16
6 DI 17 I Digital input 17
7 G1 GND Ground for DI0 - DI3, DI16, DI17 (isolated with respect to M)
8 M GND Ground
9 DI/DO 8 B Digital input/output 8 (rapid input)
10 DI/DO 9 B Digital input/output 9 (rapid input)
11 M GND Ground
12 DI/DO 10 B Digital input/output 10 (rapid input)
13 DI/DO 11 B Digital input/output 11 (rapid input)
14 M GND Ground
Signal type: B = Bidirectional; I = Input; GND = Reference potential (ground)
DI: Digital input; DI/DO: Bidirectional digital input/output; M: Ground M1: Ground reference
Please take the technical data of the digital inputs/outputs from Chapter Technical data 
(Page90).
NOTICE
Ensuring the function of the digital inputs
An open input is interpreted as "low".
The "rapid inputs" can be used for position detection and as inputs of probes depending on the 
associated terminal assignment.
To enable digital inputs 0 to 3 to function, terminal G1 must be connected. This can be done as 
follows:
• Connect the ground reference of the digital inputs.
• A jumper to terminal M (note that these digital inputs are then no longer electrically 
isolated).
Note
For a transient (brief) voltage interruption of the 24 V supply, the digital outputs are switched 
inactive for this time.
Connectable components
12.1NX10.3/NX15.3
NCU 1750
Equipment Manual, 10/2023, A5E45627807B AH 109