Siemens NCU 7x0.3 PN Series Manual page 100

Connectable components
9.2 PP 72/48D PN
Digital inputs
The 24 V supplied at X1 are used to supply the 72 digital inputs.
If the internal supply voltage is not used to supply the digital inputs, this can optionally be
replaced by an external power supply (24 V DC). The reference ground of the power supply
source must each be connected with X111, X222, X333, pin 1 (GND). X111, X222, X333, pin
2 (P24OUT) then remains open.
Digital outputs
To supply (24 V DC) the digital outputs, an additional external power supply source is
required. The power supply is connected to terminals X111, X222 and X333 via pins 47, 48,
49 and 50 (DOCOMx). Ground pins must be connected to a common chassis ground.
Maximum current consumption: 3 x 4 A if all outputs are used simultaneously.
CAUTION
It is the user's responsibility to ensure that the max. current consumption per DOCOMx pin
(X111, X222, X333: Pins 47, 48, 49, 50) does not exceed 1 A. The power supply (+24 V
DC) for the digital outputs must therefore be connected to all 4 pins per DOCOMx (X111,
X222, X333: pins 47, 48, 49, 50).
Wiring the power supply
Table 9- 14
Pin
1
2
3
Current requirement
0.7 A (at 24 V DC) for PP 72/48D PN and digital inputs plus 3 x 4 A at X111, X222 and X333
for supplying digital outputs.
Wiring the screw-type terminal block
The required 24 VDC load power supply is wired to the screw-type terminal block (X1).
The 24 V direct voltage is to be configured as an extra-low voltage with protective
separation - DVC A or PELV.
100
Pin assignment at X1 screw-type terminal block
Signal name
P24
M
PE
DANGER
Signal type Meaning
VI 24 V DC power supply
GND Ground
GND Protective ground
NCU 7x0.3 PN
Manual, 09/2011, 6FC5397-1EP40-0BA0