Calculation Of Power Loss; Feedback Energy In Do Modules - Weidmüller u-control UC20-WL2000-AC-CAN Manual

4.10 Calculation of power loss

The power loss of the controller is calculated as follows:
P = P + N * P + I
controller 0 mod in
P Static power loss in the controller
0
I Current consumption from the system current
SYS
path
N Number of modules
P Power loss due to module supply from the
mod
system current path
I Current fed in through the input current path
in
ΔU Voltage drop across the contacts in the input
in
current path
I Current fed in through the output current path
out
ΔU Voltage drop across the contacts in the output
out
current path
The power loss of a u-control station is calculated using
the power loss of the controller and the power loss of the
individual modules. It depends on the current in both current
paths. It is assumed that there is a maximum power loss
( P ) of 2 watts for the modules.
module
P = P + N * P
station controller module
Maximum values were assumed for these calculations. If you
need detailed calculations, please contact the Weidmüller
Service.
Calculation of power loss for the use in a potentially explo-
sive atmosphere
You will find the module specific data needed for calculation
in the document "WI13ATEX0002_Power_Calc.pdf" which
you can download from the Weidmüller Support Center.
2604080000/08/08.2023
* ΔU + I * ΔU
in out out
24 V * I
See table "Cur-
rent demand" in
section 4.8
0.02 W
0.18 V
0.18 V

4.11 Feedback energy in DO modules

With digital output modules, power is fed back through the
channels when inductive loads are switched off. The respec-
tive permissible breaking energy is noted in the technical
data of the DO modules. Depending on the switching fre-
quency the breaking energy leads to additional energy loss
SYS
in the output module.
Observe the specifications in the Remote-I/O-
System u-remote Manual.
All manuals are available to download from the
Weidmüller website.
If the maximum permissible output power loss of a module
is exceeded, the module shuts down temporarily.
Feedback energy can be prevented by installing
external free-wheeling protection. With it, the
same switching rate can be achieved with an in-
ductive load as with a resistive load.
Manual u-control 21