User manual

4 Conguration | Example calculation for the power supply
24 1432790000/08/12.2015Manual u-remote
Current demand
Product group Product I
SYS
I
IN
I
OUT
I
S
I
L
Power-feed modules
UR20-PF-O 10 mA
UR20-PF-I 10 mA
UR20-PF-O-1DI-SIL, UR20-PF-O-2DI-SIL, UR20-PF-O-2DI-DELAY-SIL 8 mA 45 mA x
Potential distribution
modules
UR20-16AUX-O
– – – – –
UR20-16AUX-I
– – – – –
I
SYS
Current consumption from the system current path
I
IN
Power consumption from input current path (*all inputs active)
I
OUT
Power consumption from output current path at maximum load
I
S
Current demand of the connected sensors
I
L
Current demand of the connected actuators
x
Must be included when calculating the power supply
4.6 Example calculation for the power supply
The power supply must be calculated individually for each
station installation. Therefore the simultaneity factor g and
the current demand of each module, as well as the devices
to be connected must be established (see the example calcu-
lation table).
In the example station, a PROFINET-IRT coupler is cong-
ured with four UR20-4DI-P modules and eight UR20-8DO-P
modules. The cumulative current demand for each module is
now calculated to determine whether and at which point a
UR20-PF-I power-feed module must be positioned to refresh
the current path. A power-feed module must always be used
where the current demand exceeds 10 A.
The power refresh must be separately calcu-
lated for the input and output current paths.
The system voltage need not be considered
during this step.
Calculation of the current demand for the input current
The current consumption of the eldbus coupler must be
considered for the main power supply, and the sum of
consumption values is multiplied by the simultaneity factor g
for each following module:
I
SYS
coupler
+ (I
SYS
+ I
IN
)+ (I
S
x g) module 1
+ (I
SYS
+ I
IN
)+ (I
S
x g) module 2
+ ∑((I
SYS
+ I
IN
)+ (I
S
x g)) modules 3 to 4
= Cumulative current demand
I
SYS
Current consumption from the system current path
I
IN
Current consumption from the input current path
I
S
Power supplies for the connected sensors
In the case of an additional power supply (power refresh)
with a UR20-PF-I power-feed module, only the sensor power
supplies and the module current consumption have to be
considered:
((I
IN
+ I
S
module x) x g)
+ ((I
IN
+ I
S
module y) x g)
+ ∑((I
IN
+ I
S
) x g) n modules
= Cumulative current demand