How can I run the system when sensors blocked at the energy waving?


Thread Starter


We have PLC 115U's that controls the Baggage Handling System in a Terminal. These PLCs have wired with UPS except IBS panels. If there is an energy failure for a second you should remove all baggages in front of photocell before restart the system.
I want to add a new FB that will only be activated in an energy failure, so that I will able to restart it unless clear the photocell.
I took PLC courses but I am new. Could you help me to create this new block?

Mechanical Engineer
[email protected]

Hakan Ozevin

OB22 is for this purpose. Set a bit (say F100.0) in OB22. Then jump to an FB at the *first line* of OB1 conditionally with this bit. At the FB write the followings:
L KF +0
T IW xx
T IW yy
T (the other necessary inputs to be cleared)
R F100.0

The program will not see the inputs for the first cycle after power on, if this helps. It depends on the program that the inputs should be cleared upto another condition (for example pressing the start button). Then you may try to reset F100.0 not at the FB, but after this condition. But in this case be very careful about choosing the inputs to be cleared. Blocking inputs may result in severe results.

If you need further help you can contact me. I think we are both from Istanbul.

Hakan Ozevin
Alvin Ltd. Sti.
Tel: (212) 272 2737