Allen-Bradley Panelview was work horse on the plant floor in 1990s. It is out of AB’s support as 2013. However, there are still a lot of legacy systems at work. It is interesting to investigate how it handles tag values at various situation at start up.
Tag Values at start up
There are multiple secenros of panelview starting up:
- Panelview losts power and starting up after power is restored. Tag values are controlled by power up setting under Application Settings -> Power Up. It can be set at write to controller with either presets or last terminal states. Use last terminal states is selected on the picture below.
- Panelview power up after an application download. This is more complicated. Since panelview has no history of tag’s last state, it writes tags initial values to the controller – regardless the tag is used or not.
Due to Panelview’s behavior, it is better to set panelview not to write to controller at start up so controller can maintain its last setting.