Reason for placing communication in cyclic interrupt block?

richas

Member
Join Date
Mar 2015
Location
asdasd
Posts
1
Hi

I am very new to the field of PLC programming. I am programming an anticollision program on a Siemens SIMATIC ET200S.

I have learned that it is common to place the communication part of the program in a cyclic interrupt block (OB35 in my program), but I don't have a clear reason as to why.

Could anyone give me a short explanation as to why I do this?
 
This is done in order to ensure consistant timing for the communications calls (say, every 10ms for example). If you do this in OB1 then the timing will vary depending on program load. Even using a Timer to trigger the comms doesn't help here because the Timer's accuracy varies depending on program load and resulting execution (cycle) time.
 

Similar Topics

Good Afternoon , I have a Powerflex 70 Drive . It faulted out with a #12 HW OverCurrent Fault . With your experience , what is the...
Replies
5
Views
7,121
UL 508: Any reason I can't supply a 60W 24VDC power supply from 2 legs of 480VAC? Our MechE is asking, it is for a product I don't deal with. My...
Replies
12
Views
5,856
Hello, I am having an issue with 1756-IT16 modules going out at a client’s location. This has been the issue from the very start. The modules will...
Replies
0
Views
919
Hi guys, First post here but i really need your help on this Devicenet communication error. I have 5 electrical panels wired the same way, but one...
Replies
6
Views
2,769
Dear All, I am working on machine in which Allen bradley SLC 5/03 CPU (1747-L531E) is installed,i am having error again and again don't know...
Replies
10
Views
2,534
Back
Top Bottom