Example Calculation For The Power Supply - Weidmüller u-control UC20-WL2000-AC-CAN Manual

4.9

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. The first power-feed module
must always be used where the current demand exceeds 5 A,
every further one after max. 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 controller
SYS
+ (I + I ) + (I x g) module 1
SYS IN S
+ (I + I ) + (I x g) module 2
SYS IN S
+ ∑ ((I + I ) + (I x g)) modules 3 to 4
SYS IN S
= Cumulative current demand
I Current consumption from the system current path
SYS
I Current consumption from the input current path
IN
I Power supplies for the connected sensors
S
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 + I module x) x g)
IN S
+ ((I + I module y) x g)
IN S
+ ∑ ((I + I ) x g) n modules
IN S
= Cumulative current demand
2604080000/08/08.2023
4 Configuration | Example calculation for the power supply
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 + (I x g) module 1
OUT L
+ (I + (I x g) module 2
OUT L
+ ∑ (I + (I x g)) n modules
OUT L
= Cumulative current demand
I module current consumption from the output current path
OUT
I Current demand of the connected actuators
L
Example:
The values in the following table are used to calculate the ex-
emplary 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 5 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
Modul 6:
I = 1.015 A + (0.015 A + (4 A x 0.5) = 3.03 A
Module 7:
I = 3.03 A + (0.015 A + (3 A x 0.5) = 4,545 A
Module 8 (without power refresh):
I = 4.545 A + (0.015 A + (2 A x 0.5) = 5,56 A
Therefore the available 5 A would be exceeded. As a result, a
PF-O power-feed module must be positioned before the 8th
module, which will supply 10 A again. The calculation of cur-
rent consumption is repeated for each power-feed module.
Unused current values may not be included.
Module 8 (as per PF-O):
I = (0.015 A + (2 A x 0.5) = 1.015 A
Module 9 (as per PF-O):
I = 1,015 A + (0.015 A + (1,2 A x 0.5) = 1,63 A
Manual u-control 19