Siemens SINUMERIK 840D sl Equipment Manual page 105

Requirements placed on the DC power supply
Inadequately fused supply cables can be life-threatening
In the case of supply lines > 10 m, protectors must be installed at the device input in order to
protect against lightning (surge).
The DC power supply must be connected to the ground/shield of the I/O module for EMC and/
or functional reasons. For EMC reasons, this connection should only be made at one point; see
also EMC Installation Guide.
Table 9-13
Rated voltage
Non-periodic overvoltages
Transient voltage interrup‐
tions
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.
NCU 7x0.3B PN
Equipment Manual, 10/2020, 6FC5397-1EP40-6BA1
WARNING
Requirements of the DC power supply
According to EN 61131-2
Voltage range (average value)
Voltage range (dynamic)
Voltage ripple peak-to-peak
Booting time at POWER ON
Duration of overvoltage
Recovery time
Events per hour
Outage time
Recovery time
Events per hour
Connectable components
9.2 PP 72/48D PN
24 V DC
20.4 V DC to 28.8 V DC
18.5 to 30.2 V DC
5% (unfiltered 6-pulse rectifi‐
cation)
Any
≤ 35 V
≤ 500 ms
≥ 50 s
≤ 10
≤ 3 ms
≥ 10 s
≤ 10
105