Weidmüller 1334950000, Manual

Page: 19 / 84

4 Configuration | Example calculation for the power supply
19 Manual u-control 2604080000/03/08.2020
4.7 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 UC20-WL2000-AC controller
is configured 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 posi-
tioned 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 calculated
for the input and output current paths. The sys-
tem voltage need not be considered during this
step.
Calculation of the current demand for the input current
The current consumption of the controller must be consid-
ered for the main power supply , and the sum of consump-
tion values is multiplied by the simultaneity factor g for each
following module:
I
SYS
controller
+ (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
Calculation of current demand for the output current
The current consumption of each module and the current
demand of the connected actuators must be considered for
the output current. There is no difference in the calculation
of the main power supply and power refresh:
(I
OUT
+ (I
L
x g) module 1
+ (I
OUT
+ (I
L
x g) module 2
+ ∑ (I
OUT
+ (I
L
x g)) n modules
= Cumulative current demand
I
OUT
module current consumption from the output current path
I
L
Current demand of the connected actuators
Example:
The values in the following table are used to calculate the
current demand of the example station (cumulative for each
module). The input current is:
Module 1:
I = 0.116 A + (0.008 A + 0.012 A) + (0.06 A x 1) = 0.196 A
Module 2:
I = 0.196 A + (0.008 A + 0.012 A) + (0.06 A x 1) = 0.276 A
The values for the other modules are calculated accordingly.
The result shows that the accumulated value for up to 12
modules remains under 10 A, and therefore a power-feed
module need not be used for the input current path.
Results for the output current path:
Module 5:
I = 0.015 A + (2 A x 0.5) = 1.015 A
Modul6 6:
I = 1.015 A + (0.015 A + (4 A x 0.5) = 3.03 A
Module 10:
I = 6.175 A + (0.015 A + (4 A x 0.5) = 8.19 A
Module 11 (without power refresh):
I = 8.19 A + (0.015 A + (4 A x 0.5) = 10.205 A
Therefore the available 10 A would be exceeded. As a result,
a PF-O power-feed module must be positioned e 11th mod-
ule, which will supply anocalculation of current consumption
is repeated for each power-feed module. Unused current
values may not be included.
Module 11 (as per PF-O):
I = (0.015 A + (4 A x 0.5) = 2.015 A
Module 12 (as per PF-O):
I = 2.015 A (0.015 A + (4 A x 0.5) = 4.030 A