GE RSTi-EP

Chapter 3: Configuration
GFK-2958E RSTi-EP User Manual 32
3.6.2 Calculation of the 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
+ Σ (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 supply module need not be
used for the input current path. Results for the output current path:
Module 5:
I = 0.015 A + (0.5 A x 2) = 1.015 A
Module 6:
I = 1.015 A + (0.015 A + (0.5 A x 4) = 3.03 A
Module 10:
I = 6.175 A + (0.015 A + (0.5 A x 4) = 8.19 A
Module 11 (without power refresh):
I = 8.19 A + (0.015 A + (0.5 A x 4) = 10.205 A
Therefore the available 10 A would be exceeded. As a result, an EP-7641 power supply module must
be positioned as the 11th module, which will supply the required power to the subsequent modules
after the power feed module. Unused current values may not be included.
Module 11 (as per PF-O):
I = (0.015 A + (0.5 A x 4) = 2.015 A
Module 12 (as per PF-O):
I = 2.015 A (0.015 A + (0.5 A x 4) = 4.030 A