Doors/Elevator does not work when SCU/DPU is disconnected
I/NET with Access Control Site
Why disconnect the 7798C from the SCU? In normal operating situations, this communication is always there, always working. Hopefully the network provided and the wires which tie the 7798C to the SCU are good and not an issue. If this is not the case, redo so that this communication is stable and constant.
The SubLAN should hopefully always be connected. This RS-485 network should be stable. If not, investigate.
First though is site is using large numbers. When disconnect the 7798C from the SCU, the elevator does not work. The reason the large numbers are stored in the 7798C and not in the SCU. If the individual is set to resident in the SCU then those are the only ones allowed to use the elevator. The others look to the SLI for permission to use the elevator.
The SCU must remain in contact with the 7798C when controlling elevators. The communication between the SCU and the SLI, such as a 7798C, is required since an elevator is involved. The time schedules and floor mapping are in this SLI that is requested upon each time the elevator is used.
For more information on the I/NET network and environment, check Lessons Learned Article #4551.