Eaton easyE4 series Manual page 506

9. easyE4 inside
9.1 Program execution
502
During this time, the easyE4 device passes through six segments in succession.
If the operands of the inputs and outputs are addressed in the easyE4, the signal states
of the digital inputs/outputs are not scanned but a memory range in the device system
memory is accessed. This memory range is called the process image. The process
image is divided into two sections: the process image for the inputs and the process
image for the outputs.
Segment 1 - 4
The easyE4 device evaluates the contact fields within the first four segments. The eval-
uation starts in the first segment in circuit diagram line 1 and continues from top to bot-
tom until circuit diagram line n is reached.
The easyE4 device then moves to the next contact segment and continues to evaluate
from top to bottom until it has reached the last contact in the fourth segment. During this
process it checks whether contacts are switched in parallel or in series and saves the
switching states of all contact fields.
Segment 5
In the fifth segment the easyE4 device assigns all coils in one pass, from the circuit dia-
gram line 1 - n, with the new switch states from the process image of the outputs.
easyE4 11/18 MN050009 EN www.eaton.com
NET sta-
tions
inputs
puts